DRINKING WATER QUALITY AND MANAGEMENT STRATEGIES …
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HOUSSEINI DIADIÉ COULIBALY DRINKING WATER QUALITY AND MANAGEMENT STRATEGIES IN SMALL QUEBEC UTILITIES Thèse présentée à la Faculté des études supérieures de l'Université Laval pour l’obtention du grade de Philosophiae Doctor (Ph.D.) Département d’Aménagement du territoire et développement régional FACULTÉ D’AMÉNAGEMENT, D’ARCHITECTURE ET DES ARTS VISUELS UNIVERSITÉ LAVAL QUÉBEC 22 DÉCEMBRE, 2003 © Housseini Diadié Coulibaly, 2003
Transcript of DRINKING WATER QUALITY AND MANAGEMENT STRATEGIES …
HOUSSEINI DIADIÉ COULIBALY DRINKING WATER QUALITY AND MANAGEMENT
STRATEGIES IN SMALL QUEBEC UTILITIES
Thèse présentée
à la Faculté des études supérieures de l'Université Laval
pour l’obtention du grade de Philosophiae Doctor (Ph.D.)
Département d’Aménagement du territoire et développement régional FACULTÉ D’AMÉNAGEMENT, D’ARCHITECTURE ET DES ARTS VISUELS
UNIVERSITÉ LAVAL QUÉBEC
22 DÉCEMBRE, 2003 © Housseini Diadié Coulibaly, 2003
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Abstract This thesis presents a study of small Quebec municipal utilities (i.e., serving 10,000 people
or fewer) and includes three chapters. The first chapter focuses on a portrait of historical
quality of distributed water and on management strategies. Concurrently, it puts historical
quality and management strategies in relation to certain important water quality parameters.
Results show that for surface water utilities using chlorination alone, the mean difference of
annual system flushings between utilities that have experienced difficulties with historical
quality and those not having experienced such difficulties proved statistically significant. In
addition, some agricultural land-use indicators within the municipal territory appeared
significantly correlated with coliform occurrences. The second chapter studies the spatial
and temporal variation of drinking water quality in ten small utilities. These utilities were
divided into two groups: four utilities that had never or rarely served water violating the
provincial drinking water microbiological standards and six utilities that very often
infringed upon said standards. Results show that the differences between the two groups of
utilities are associated essentially with maintained chlorine residuals and heterotrophic
plate count bacteria populations in corresponding distribution systems and, to a lesser
extent, to the applied chlorine doses. The study includes three distinctive parts: the first one
is a portrait of studied utilities’ operational, infrastructure, and maintenance characteristics;
the second part is devoted to development of indicators of performance for the same
utilities, whereas the last part deals with human and organisational factors. The portrait
revealed interesting trends, most of which had been confirmed by utility performance
indicators. As for human and organizational factors, they allowed highlighting such issues
like educational background, supplementary training, experience, awareness of and
preparedness to take up new challenges, and support from local authorities. Overall, this
research enabled a thorough investigation of management strategies the most popular with
small drinking water utilities and the development of explanatory tools that may usefully
guide action from local managers and government bodies.
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Key words: drinking water, water quality, small utilities, distribution system, coliform
occurrences, performance indicators, human factor, province of Quebec
Housseini D. Coulibaly Manuel J. Rodriguez, Ph.D., Professor
Author Supervisor
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Résumé La présente thèse porte sur une étude des petits systèmes municipaux du Québec (en
l’occurrence, ceux desservant 10 000 personnes ou moins) et comporte trois volets. Le
premier volet se focalise sur un portrait historique de la qualité de l’eau distribuée et sur les
stratégies de gestion. Parallèlement, il met l'historique de la qualité et les stratégies de
gestion en relation avec certains paramètres importants de la qualité de l’eau. Les résultats
de ce volet montrent que pour les systèmes s’approvisionnant en eau de surface et
pratiquant uniquement une chloration, la différence entre le nombre annuel moyen de
rinçages des systèmes ayant connu des problèmes de qualité et ceux n’ayant pas connu de
tels problèmes s’est avérée statistiquement significative. En plus, certains indicateurs de la
pression agricole sur le territoire des municipalités concernées apparurent significativement
corrélés avec les épisodes de coliformes. Le deuxième volet porte sur une étude de la
variation spatio-temporelle de la qualité de l’eau dans dix petits systèmes. Ces systèmes
furent répartis en deux groupes : quatre systèmes qui n’ont jamais ou ont rarement distribué
de l’eau dérogeant aux normes microbiologiques provinciales relatives à l’eau potable et six
systèmes qui ont très souvent dérogé auxdites normes. Les résultats montrent que les
différences entre les deux groupes de systèmes sont essentiellement imputables aux teneurs
en chlore résiduel libre et au nombre de colonies de bactéries hétérotrophes aérobies et
anaérobies facultatives (BHAA) dans les réseaux de distribution correspondants et, dans
une moindre mesure, aux doses de chlore appliquées. Le troisième volet inclut trois
parties : la première est un portait des caractéristiques d’opération, de l’infrastructure et de
la maintenance ; la deuxième est consacrée au développement d’indicateurs de performance
pour les petits systèmes ; alors que la troisième traite des facteurs humains et
organisationnels. Le portrait a révélé des tendances intéressantes qui ont presque toutes été
confirmées par les indicateurs de performance des systèmes de distribution. Les facteurs
humains et organisationnels dégagèrent des aspects tels que les antécédents scolaires, la
formation complémentaire, l’expérience, la bonne conscience des nouveaux défis, le niveau
de préparation pour y faire face, et l’appui des autorités locales. Dans son ensemble, cette
recherche aura permis de procéder à une étude exhaustive des stratégies de gestion de la
qualité de l’eau potable généralement mises de l’avant par les gestionnaires de petits
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systèmes et de développer des outils explicatifs pouvant guider utilement leur action, de
même que celle des gestionnaires relevant des divers paliers gouvernementaux.
Mots-clés : eau potable, qualité de l’eau, petits systèmes, systèmes de distribution, épisodes
de coliformes, indicateurs de performance, facteur humain, province du Québec
Housseini D. Coulibaly Manuel J. Rodriguez, Ph.D., Professeur
Auteur Directeur de recherche
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Remerciements À tout seigneur, tout honneur… ! Je ne pouvais entamer cette page de remerciements que
par des mots de reconnaissance à l’endroit de mon Directeur de recherche, le Professeur
Manuel J. Rodriguez. Certes, le chemin fut long, tortueux, parfois difficile, mais votre
soutien et votre engagement, je dirais votre totale détermination à me mener à bon port dans
le cadre de ce programme de doctorat, m’ont permis d’y croire même aux moments les plus
difficiles et, enfin, d’y arriver. Permettez-moi donc, en cet instant des plus solennels pour
moi, de vous exprimer ma plus profonde gratitude pour tous les services académiques et
extra-académiques dont j’ai eu le bonheur d’être l’objet de votre part au cours de ces
années de doctorat. Puissé-je être digne de ce dévouement, de cette insigne marque de
confiance, imprégné et inspiré par un tel exemple d’engagement pour le restant de mes
jours ! Merci du fond du cœur !
Même si cela est souvent passé sous silence, une thèse de doctorat couronne toujours les
efforts de tout un groupe de personnes, en l’occurrence le candidat, son Directeur ou
Directrice de recherche, et les membres du Comité de suivi. Ces derniers, qui ont accepté
d’embarquer avec moi dans cette aventure à un moment où l’issue finale était loin d’être
certaine, me témoignant ainsi de leur confiance quant à ma capacité à mener le projet à son
terme, ont droit ici à ma plus grande reconnaissance. Leurs précieux conseils, suggestions
et recommandations ont significativement contribué à donner à cette thèse forme et surtout
contenu. Que les professeurs Jean-Baptiste Sérodes, Michel Trépanier et Patrick Levallois,
car c’est bien d’eux qu’il s’agit, trouvent donc en ces mots l’expression de ma plus
profonde gratitude. Je tiens par ailleurs à faire mention spéciale de l’honneur que m’a fait le
Professeur Jean-Baptiste Sérodes en acceptant d’être le prélecteur de cette thèse malgré ses
lourdes fonctions de Doyen de la Faculté des Sciences et Génie de l’Université Laval. En
outre, je lui dois de précieuses lettres de recommandation. Puisse-t-il donc trouver ici
l’expression de ma plus profonde reconnaissance pour tous ces gestes hautement empreints
de sollicitude.
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L’argent, dit-on, et non sans raison, est le nerf de la guerre. C’est l’Agence Canadienne
pour le Développement International (ACDI) qui m’a permis de faire ce doctorat en
m’accordant une bourse d’études dans le cadre du Programme Canadien de Bourses de la
Francophonie (PCBF). À l’ACDI, en sa qualité d’agence d’exécution du Gouvernement
Canadien, et aux différents organismes auxquels la gestion quotidienne des boursiers du
PCBF a été successivement confiée au cours de mes années d’études, à savoir le Ministère
de l’Éducation du Québec, l’Association des Universités et Collèges du Canada (AUCC) et,
présentement, le Collège Saint-Jean-sur-Richelieu, je voudrais exprimer ici mes sincères
remerciements. Je voudrais également les assurer de ma profonde volonté de mettre les
compétences qu’ils m’ont permis d’acquérir au service du développement de mon pays, le
Mali, et du développement international, partout où mes activités futures me conduiront.
Le Ministère de l’Environnement du Québec, par l’entremise de ses employés, a été l’un de
mes principaux pourvoyeurs de données. Je voudrais mettre à profit cette tribune pour
remercier vivement Messieurs Alain Riopel et Donald Ellis, de même que Mesdames
Yolaine Blais et Isabel Parent pour avoir, à plus d’une reprise, promptement et
généreusement acquiescé à mes demandes de données. À Messieurs Alain Riopel et Donald
Ellis, je dois de la reconnaissance non seulement pour des données, mais également pour de
judicieux conseils et suggestions.
Puissent les gestionnaires principaux des dix petits systèmes municipaux étudiés dans les
chapitres 2 et 3 de cette thèse, ainsi que leurs adjoints ou suppléants, trouver ici
l’expression de ma totale gratitude pour n’avoir rien ménagé pour la réussite des volets de
la recherche ayant requis leur concours. À tous, je dis un grand merci pour cette marque de
compréhension et de responsabilité.
Que Monsieur Michel Bisping du laboratoire de Génie de l’Environnement trouve en ces
mots toute ma reconnaissance pour son aide, son amabilité. Je ne saurais oublier non plus
mes collègues étudiants, membres du Groupe de Recherche sur l’Eau Potable de
l’Université Laval (GREPUL), à qui je dois une fière chandelle pour leur grande
disponibilité.
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Outre Atlantique, mes remerciements vont à tous ceux qui, à la société Énergie du Mali
(EDM), ont permis, de par leur franche collaboration, la réussite du stage que j’y ai effectué
au cours de l’été 2000. Dans ce cadre, j’aimerais faire mention toute spéciale des membres
de la Direction de l’eau et des employés du laboratoire de l’usine d’eau potable de Bamako.
Le département d’Aménagement du Territoire et Développement Régional (ATDR) et le
Centre de Recherche en Aménagement et Développement (CRAD) ont été mon point
d’ancrage à l’Université Laval. Je voudrais en tout premier lieu exprimer mes vifs
remerciements au Professeur émérite Peter Brook Clibbon, aujourd’hui à la retraite, pour
avoir été celui qui a accepté ma candidature à ce programme de doctorat en sa qualité de
Directeur du Département d’Aménagement. Je remercie également le Professeur Mario
Carrier, actuel Directeur du Département, pour avoir accepté de prendre de son temps, que
je sais des plus précieux, pour faire, à ma demande, lecture critique de la partie de cette
thèse portant sur les facteurs humains. Ma reconnaissance s’adresse également au
Professeur Marius Thériault, Directeur du CRAD, pour le soutien financier et logistique
dont j’ai pu bénéficier de la part dudit centre tout au long de mon doctorat. Au Professeur
Claude Lavoie, Directeur actuel du Programme de Doctorat en ATDR, je voudrais exprimer
ma profonde gratitude pour avoir accepté de présider mon Jury de thèse, mais également
pour avoir spontanément acquiescé à toutes mes demandes de lettres de recommandation.
Je remercie tous les autres professeurs du Département pour leur disponibilité et leur
sollicitude. Un grand merci également de ma part aux adjoints et secrétaires aux deux
directions (ATDR et CRAD) pour leur gentillesse, efficacité et … sourire. Je ne saurais
oublier mes collègues étudiants au doctorat, à qui j’adresse mes sincères remerciements
pour leur disponibilité à chaque fois que j’ai eu recours à leurs services ou avis. Je tiens à
faire mention spéciale des cas de Messieurs Rémy Barbonne et Yan Kestens, deux
collègues devenus de vrais amis. Merci à tous les deux de votre sincère amitié et de votre
soutien.
Tout commence par la famille et tout, au bout du compte, se résume en elle. En ces
moments très singuliers pour moi, j’ai une pensée tout aussi singulière pour mon père, lui
qui nous a quittés au mois de mars 2003. Papa, toi qui a été non seulement un père
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exemplaire pour moi, mais également mon ami le plus proche, mon confident, mon
conseiller, ma source d’inspiration, ma référence première et ultime, je sais que tu es
heureux et fier là-haut en voyant cette thèse ; je te la dédie. Je dis merci à ma mère et à mes
frères et sœurs pour leur soutien et encouragements. Mention spéciale est due à mon
épouse, Aminata Diombélé Coulibaly, pour avoir courageusement et volontairement
accepté d’arpenter avec moi les jalons de la difficile, très exigeante vie d’étudiant au
doctorat, requérant beaucoup de sacrifices et n’offrant que très peu de répit, de réconfort.
Ma chérie, merci pour ta confiance, ton support, tes encouragements. Enfin, je ne puis clore
ces mots de reconnaissance, sans parler de la lumière de ma vie, Anna, ma fille, qui m’offre
tant de réconfort moral et m’insuffle courage et détermination.
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Foreword The present thesis has been organized into three chapters, each of which corresponds to a
journal article. The first two chapters have already been published in scientific journals,
whereas the third one is being prepared for submission. Because of that, certain details,
dealing with the general problematics of the study, are repeated in chapter abstracts,
introductions and, sometimes, in chapter methodological parts. This slight redundancy has
been intentionally maintained in the present thesis, so that people interested in only a single
chapter (i.e., article) could have a whole understanding of it without being compelled to
consult other chapters. It is important to note that, due to publication restrictions, some
comments, as well as a number of tables and figures present in this thesis’ chapters could
not be included in journal articles. This is particularly true for the article coming from the
third chapter, as it excludes a whole section of the latter.
The order in which chapters are presented corresponds to the chronological unfolding of
research activities. The thesis author is also the first author of all included articles, with the
second author being the thesis supervisor. Apart from the thesis ones, all chapters have
their own English and French abstracts. Abstracts are preceded in Chapters 2 and 3 by
overview sections allowing to link all parts of the thesis together. Likewise, each chapter
has its own list of references. The references cited in introductory parts of the thesis and in
the general introduction are listed at the end of the latter. The references of the articles
included in the present thesis are as follows.
CHAPTER 1
Portrait of drinking water quality in small Quebec municipal utilities
Housseini D. Coulibaly and Manuel J. Rodriguez1
Published in Water Quality Research Journal of Canada, Volume 38, No. 1, pp. 49-76
(2003).
1 Département d’aménagement, Université Laval, 1624 Pavillon Savard, Quebec City, QC, G1K 7P4.
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CHAPTER 2
Spatial and temporal variation of drinking water quality in ten small Quebec utilities
Housseini D. Coulibaly and Manuel J. Rodriguez
Published in Journal of Environmental Engineering and Science, Volume 2, pp. 47-61
(2003).
CHAPTER 3
Development of performance indicators for small Quebec drinking water utilities.
Housseini D. Coulibaly and Manuel J. Rodriguez
Submitted to the Journal of Environmental Management in November 2003.
All information that could not be directly included in the three chapters has been presented
in appendices. The latter have been designated in the alphabetical order from A to H. Some
of them are survey or semi-directive interview questionnaires, while others contain raw or
worked data organized into tables.
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À mon père, Diadié Dessé Coulibaly, à qui il manqua six petits mois pour voir cette
thèse…
L’eau est, à part l’air que l’on respire, le seul nutriment qui, en terme de nécessité, est
consommé par chaque être humain du premier au dernier jour de son existence, et
elle est consommée en des quantités considérablement plus grandes que n’est le cas pour n’importe quelle autre substance
nutritive. Druckrey (1968)
Water is, apart from the air one breathes, the
only nutrient which is, as a matter of necessity, consumed by every human being
from the first day to the last day of his existence, and it is consumed in considerably
larger quantities than any other nutritional substance.
Druckrey (1968)
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Table of contents
Abstract.................................................................................................................................. ii
Résumé...................................................................................................................................iv
Remerciements.......................................................................................................................vi
Foreword.................................................................................................................................x
List of tables.........................................................................................................................xvi
List of figures.................................................................................................................... xviii
General introduction ............................................................................................................1 General references ..............................................................................................................3
CHAPTER 1 Portrait of drinking water quality in small Quebec municipal utilities...........................4
1.1. Introduction..................................................................................................................5 1.2. Small Utilities in Quebec.............................................................................................6 1.3. Source of Data .............................................................................................................7
1.3.1. Database 1.............................................................................................................8 1.3.2. Database 2.............................................................................................................8 1.3.3. Database 3.............................................................................................................9 1.3.4. Database 4...........................................................................................................10 1.3.5. Other published data ...........................................................................................10
1.4. Portrait of Small Utilities...........................................................................................10 1.4.1. General characteristics and physicochemical water quality ...............................11 1.4.2. Portrait of the microbiological water quality......................................................18 1.4.3. Strategies for maintaining microbiological water quality in the distribution system..................................................................................................22
1.4.3.1. Rechlorination practices ..............................................................................22 1.4.3.2. Pipe characteristics ......................................................................................23
1.4.4. Relationships between management strategies and microbiological water quality .................................................................................................................25 1.4.5. Relationships between agricultural land use and microbiological water quality .................................................................................................................30 1.4.6. Multivariate analyses ..........................................................................................31
1.5. Conclusions................................................................................................................33 1.6. References..................................................................................................................35
CHAPTER 2 Spatial and temporal variation of drinking water quality in ten small Quebec utilities..........................................................................................................38
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2.1. Introduction................................................................................................................41 2.2. Methodology..............................................................................................................42
2.2.1. Small utilities under study ..................................................................................44 2.2.2. Sampling program strategy.................................................................................44 2.2.3. Analytical procedures .........................................................................................46
2.2.3.1. Microbiological analyses .............................................................................46 2.2.3.2. Physicochemical analyses............................................................................48
2.3. Results and discussion ...............................................................................................50 2.3.1. Characteristics of raw water ...............................................................................51 2.3.2. Characteristics of treated and distributed water..................................................56
2.3.2.1. Chlorination levels.......................................................................................56 2.3.2.2. Microbiological water quality......................................................................58 2.3.2.3. Residual chlorine .........................................................................................59 2.3.2.4. Chlorination by-products .............................................................................63
2.4. Multivariate analyses .................................................................................................64 2.5. Conclusions................................................................................................................68 2.6. References..................................................................................................................70
CHAPTER 3 Impact of technical and human factors on water quality in ten small Quebec utilities ...................................................................................................72
3.1. Introduction................................................................................................................74 3.2. Methodology..............................................................................................................76
3.2.1. Procedure for selecting the ten utilities...............................................................76 3.2.2. Information about the distribution system infrastructure ...................................77 3.2.3. Information about the human and organizational factors ...................................79
3.3. Results and discussion ...............................................................................................81 3.3.1. Characteristics of operation, infrastructure, and maintenance............................81
3.3.1.1. Variables on distribution system operation (i.e., disinfection-related) ..................................................................................................81
3.3.1.1.1. Chlorination devices .............................................................................81 3.3.1.1.2. Mode of chlorine injection....................................................................82 3.3.1.1.3. Disinfection effectiveness.....................................................................82 3.3.1.1.4. Usual residual chlorine checkpoints .....................................................85 3.3.1.1.5. Frequency of residual chlorine measurement .......................................85
3.3.1.2. Variables on distribution system infrastructure ...........................................86 3.3.1.2.1. Utility age .............................................................................................86 3.3.1.2.2. Storage tanks.........................................................................................87 3.3.1.2.3. Pipe material .........................................................................................88
3.3.1.3. Variables on distribution system maintenance ............................................89 3.3.1.3.1. Flushing ................................................................................................89 3.3.1.3.2. Main breakage.......................................................................................90
3.3.2. Indicators of performance for small utilities.......................................................91 3.3.2.1. Development of performance indicators.....................................................91 3.3.2.2. Analysis of the indicator results..................................................................95 3.3.2.3. Sensitivity analysis of the performance indicators .....................................99
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3.3.2.3.1. Variation of sub-indicator weights .....................................................101 3.3.2.3.2. Exclusion of sub-indicators ................................................................102
3.3.3. Human and organizational factors ....................................................................103 3.3.3.1. Within-case analyses..................................................................................104 3.3.3.2. Across-case analyses..................................................................................105
3.4. Conclusions..............................................................................................................108 3.5. References................................................................................................................110
General conclusions and recommendations ...................................................................112
APPENDICES...................................................................................................................118
Appendix A.......................................................................................................................119
Appendix B .......................................................................................................................124
Appendix C .......................................................................................................................126
Appendix D.......................................................................................................................133
Appendix E .......................................................................................................................140
Appendix F .......................................................................................................................152
Appendix G.......................................................................................................................157
Appendix H.......................................................................................................................162
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List of tables Table 1.1. Water source, treatment, and disinfectant type for the surveyed utilities ........................................ 12 Table 1.2. Water quality and operational parameters for the surveyed utilities................................................ 12 Table 1.3. Portrait of the coliform appearances in investigated small
utilities (1997 through 1999)................................................................................................................... 19 Table 1.4. Distribution of population served and coliform episodes according to water
source and treatment types (for responding utilities) .............................................................................. 21 Table 1.5. Survey responses for specific distribution system characteristics (pipe age,
pipe material, main breaks, and system flushings) .................................................................................. 22 Table 1.6. Observed relationship between the chlorine dose (mg/L) and the utility
microbiological status ............................................................................................................................. 27 Table 1.7. Observed relationship between distribution system flushings and the utility
microbiological status ......................................................................................................................... 28 Table 1.8. Observed relationship between distribution pipe age and the utility
microbiological status ............................................................................................................................. 28 Table 1.9. Observed relationship between distribution main breaks and the utility
microbiological status ............................................................................................................................. 29 Table 1.10. Observed relationship between agricultural pressure indicators and
microbiological characteristics of utilities............................................................................................... 32 Table 2.1. General characteristics of the ten small utilities .............................................................................. 50 Table 2.2. Comparison of mean differences between nonproblematic and problematic
utilities for raw water during the period under study .............................................................................. 56 Table 2.3. Comparison of mean differences between nonproblematic and problematic
utilities for distributed water quality at (a) chlorination facility outlet, (b) central part of distribution system, and (c) system extremity ............................................................................. 61
Table 2.4. Summary of multivariate analyses................................................................................................... 66 Table 3.1. Overview of water quality variation in the studied utilities ............................................................. 78 Table 3.2. Distribution system operational, infrastructure, and maintenance characteristics ........................... 79 Table 3.3. CT-value (mg⋅min/L) approximations for utilities at study ............................................................. 85 Table 3.4. Variables selected for sub-indicators and indicators and their relative weights (wi) ....................... 93 Table 3.5. Variables used for tap water quality indicators and their relative weights (wi) ............................... 94 Table 3.6. Relative level of performance (γi ) of each utility on the considered variables ............................... 96 Table 3.7. Identified sub-indicators and indicators of performance
for individual utilities (real values) ......................................................................................................... 97
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Table 3.8. Identified sub-indicators and indicators of performance
for individual utilities (interpreted values) .............................................................................................. 97 Table 3.9. Recapitulation of developed indicators of performance .................................................................. 98 Table B.1. Atypical bacteria data generated by the studied utilities from 1997 through 1999 ....................... 124 Table B.2. Distribution water boiling notices issued by the studied utilities from 1996
through 2001 ......................................................................................................................................... 125 Table C.1. Water quality data gathered in result of the 2001 sampling campaign in ten
small Quebec municipal utilities ........................................................................................................... 127 Table E.1. Socioprofessional characteristics and opinions of nonproblematic utility
managers ............................................................................................................................................... 140 Table E.2. Organizational factor specificities in nonproblematic utilities ...................................................... 143 Table E.3. Socioprofessional characteristics and opinions of problematic utility managers .......................... 145 Table E.4. Organizational factor specificities in problematic utilities ............................................................ 149 Table F.1. Distribution system infrastructure information for nonproblematic utilities ................................. 152 Table F.2. Distribution system infrastructure information for problematic utilities ....................................... 154 Table G.1. Explanations as to how the parameter values were converted into
performance scores................................................................................................................................ 157 Table H.1. Sensitivity analysis of the utility performance indicator (weight variations)................................ 162 Table H.2. Sensitivity analysis of the utility performance indicator (indicator values) .................................. 163
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List of figures Figure 1.1. Distribution of water quality parameters among responding utilities:
a, turbidity; b, colour; c, chlorine dose; and d, free chlorine residual. In brackets, number of utilities; lower bar, C10; upper bar, C90; cross, mean........................................................... 13
Figure 1.2. Average total THM concentrations according to: a, source water and treatment;
b, utility size. In brackets, number of utilities; lower bar, C10; upper bar, C90; cross, mean. GW denotes Groundwater; SW denotes Surface Water. .................................................... 17
Figure 2.1. Localization of the ten small utilities.............................................................................................. 45 Figure 2.2. Comparison of raw water quality between nonproblematic (NP) and
problematic (P) utilities: a and b, turbidity; c and d, TOC; e and f, UV254 nm . Bar, mean value; upper bar, maximum; lower bar, minimum................................................................. 53
Figure 2.3. Comparison of raw water quality between nonproblematic (NP) and
problematic (P) utilities: a and b, total coliforms; c and d, HPC bacteria; e and f, atypical bacteria. Bar, mean value; upper bar, maximum; lower bar, minimum. Atypical bacteria quantification limit was 400 cfu/100 mL................................................... 54
Figure 2.4. Comparison of applied chlorine doses between a nonproblematic (NP)
utilities and b problematic (P) utilities. Bar, mean value; upper bar, maximum; lower bar, minimum ................................................................................................................................ 57
Figure 2.5. Comparison of HPC bacteria and Atypical bacteria between a and c
nonproblematic (NP) utilities; and b and d problematic (P) utilities. Bars represent monthly means (from left: May, June, July, August, October)................................................ 60
Figure 2.6. Comparison of free chlorine and total THMs between a and c
nonproblematic (NP) utilities; and b and d problematic (P) utilities. Bars represent monthly means (from left: May, June, July, August, October)................................................ 62
Figure 3.1. Relationships between utility performance indicators and current tap
water quality indicators in nonproblematic (NP) utilities with those in problematic (P) utilities ......................................................................................................................... 100
Figure 3.2. Relationship between utility performance indicator and current (2001)
microbiological tap water quality.......................................................................................................... 100 Figure 3.3. Graphical representation of the relationship between the utility performance
indicator (upi) and the current tap water quality indicator (twi)............................................................ 101 Figure 3.4. Clustering of the studied utilities according to the level of their being
nonproblematic or problematic ............................................................................................................. 104
General introduction The issue of access to potable water is becoming more and more worrying on a world scale.
The population of the Earth continues to grow fast, especially in developing countries,
while water resources, particularly those suitable for drinking purposes, are undergoing
rapid depletion (Petrella, 2001). At the same time, other, traditional, challenging issues
related to drinking water supply are swiftly gaining topicality and acuity. These challenges
bear on the necessity to maintain and, whenever possible, to improve the quality of raw
waters from the source to the ultimate consumer’s tap. All stakeholders of the drinking
water industry work unceasingly towards that objective, through new, state-of-the-art
equipments, technologies, as well as scientific knowledge. And that process is widely
supported and encouraged by national governments and international institutions (e.g.,
United Nations development agencies) through granting of funds and enactment of
standards and (or) regulations.
As scientific knowledge is advancing, the drinking water standards and (or) regulations are
getting stringent. This enhances the responsibility of drinking water utility managers. Large
and medium-size utilities, having sufficient financial and technical resources at their
disposal, generally take up the challenge by acquiring new equipments and (or) embracing
new technologies. But small utilities, often lacking adequate financial, technical, and
managerial capacity (USEPA 1999), cannot follow the beat, especially with present-day
very rapidly evolving and getting outdated water treatment processes.
One of the most important challenges in contemporary drinking water treatment and supply
relates to ensuring adequate simultaneous micro-organism inactivation in the plant and
control in the distribution system while minimizing the formation of potentially
carcinogenic disinfection by-products (DBPs) such as trihalomethanes (THMs) (Fowle and
Kopfler 1986; Putnam and Graham 1993). Large and medium-size utilities often easily
resolve the problem by applying relatively sophisticated treatment processes varying from
conventional treatment (i.e., coagulation, flocculation, sedimentation, filtration, post-
disinfection) to membrane technologies involving nanofiltration or ultrafiltration.
Moreover, only large utilities are normally capable of using very powerful oxidants like
2
ozone (O3), hydrogen peroxide (H2O2), and chlorine dioxide (ClO2) that require very
qualified personnel for appropriate handling as well as sophisticated equipments and
processes to be produced. For small utilities however, the challenge of simultaneously
ensuring adequate micro-organism inactivation and DBP control can turn out to be truly
overwhelming, especially for utilities serving surface waters with no other treatment than
chlorination.
In North America, small drinking water utilities (i.e., those serving 10,000 or fewer people)
are known to experience much more difficulty than larger utilities to serve water that
constantly corresponds the established quality standards (AWWA 2000). In the province of
Quebec (Canada), small utilities have been found to be those most frequently violating
drinking water regulations (Gouvernement du Québec, 1997). Adding to this already
complicated situation, new Quebec Drinking Water Regulations (QDWR) (Gouvernement
du Québec, 2001), brought big new challenges for small utility managers, since new
requirements or stringent standards are considered for turbidity of water, micro-organism
inactivation (virus, Giardia and Cryptosporidium), bacterial monitoring, minimum levels of
residual chlorine and maximum annual average THM levels in the distribution systems.
The main objective of this research is to explore ways and means that may allow small
Quebec drinking water utilities to acquire the capacity to constantly serve, on the long-term
basis, water of irreproachable quality to their customers. This main objective resulted in
three specific objectives, which are: 1) drawing an overall state-of-situation picture of
drinking water quality and management strategies in small Quebec utilities; 2) conducting
an in-depth study of current distributed water quality in a limited number of those utilities;
and 3) investigating the impact of utility operational, as well as infrastructure and
maintenance characteristics on the current distributed water quality, through development
of indicators of performance for small utilities. This specific objective also includes parallel
exploration of the impact of human and organizational factors relating to the principal
utility manager on historically distributed water quality.
In the past, very few studies have been done on these questions, particularly for small
utilities. Moreover, the multi-disciplinary nature of the study (encompassing technical, as
3
well as physical planning and human aspects) confers it a particular stamp. Therefore,
although this research can be considered a case study exclusively conducted in Quebec, its
results may be useful for utility managers and government bodies in many other areas
around the world.
General references AWWA. 2000. Disinfection at small systems. AWWA Water Quality Division Disinfection Systems
Committee report. J. Am. Water Works Assoc. 92:24–31. Druckrey, H. 1968. Chlorientes Trinkwasser, Toxizitäts-Prüfungen an Ratten über sieben Generationen. Food
Cosmet. Toxicol. 6: 147-154. Fowle III, J.R., and Kopfler, F.C. 1986. Water disinfection : microbes versus molecules – an introduction of
issues. Environmental Health Perspectives 69: 3–6. Gouvernement du Québec. 1997. L’eau potable au Québec, un second bilan de sa qualité : 1989–1994.
Ministère de l’Environnement et de la Faune, Québec, 36 p. Gouvernement du Québec. 2001. Règlement sur la qualité de l’eau potable. Ministère de l’Environnement,
Québec, 19 p. Petrella, R. 2001. The water manifesto: arguments for a world water contract. London : Zed Books ; Halifax,
N.S. : Fernwood publishing. Putnam, W.S., and Graham, J.D. 1993. Chemicals versus microbials in drinking water: a decision sciences
perspective. J. Am. Water Works Assoc. 85: 57–61. USEPA. 1999. Handbook for capacity development: developing water system capacity under the Safe
Drinking Water Act as amended in 1996. United States Environmental Protection Agency, Office of Water (4606), EPA 816-R-99-012.
CHAPTER 1 Portrait of drinking water quality in small Quebec
municipal utilities
Abstract. This study of small Quebec municipal drinking water utilities (i.e., those
serving 10,000 or fewer people) focuses on a portrait of microbiological water quality
(based on total and fecal coliform data) and distribution system management strategies. It
also addresses relationships between some important water quality and operational
parameters and management strategies on the one hand, and total or fecal coliform
occurrences, on the other. Along with descriptive analyses, statistical means tests (Student
t-tests) were performed to identify significant differences between utilities with high
coliform occurrence and utilities with low coliform occurrence according to chlorine dose,
distribution system flushings, pipe age, main breakage, and some environmental factors.
Even though many interesting trends have been noted, only few of them resulted in
statistically significant differences. For surface water utilities using chlorination alone, the
mean difference of annual system flushings proved statistically significant. In addition,
some agricultural land use indicators within the municipal territory appeared significantly
correlated with coliform occurrences.
Key words: drinking water, water quality, small utilities, coliform occurrences, distribution
system, Quebec
Résumé. Cette étude des petits systèmes municipaux de distribution d’eau potable du
Québec (à savoir, ceux desservant 10 000 personnes ou moins) se focalise sur un portrait de
la qualité microbiologique (basé sur des données de coliformes totaux et fécaux) et sur les
stratégies de gestion des systèmes de distribution. L’étude s’intéresse également aux
relations entre certains paramètres importants de qualité d’eau et les stratégies de gestion,
de même que les épisodes de coliformes totaux ou fécaux. Parallèlement aux analyses
descriptives, des tests statistiques de moyenne (tests du t de Student) ont été réalisés afin
d’identifier les différences significatives entre les systèmes avec des épisodes fréquents de
coliformes et les systèmes avec très peu de ces épisodes, et ce, en se basant sur les doses de
chlore administrées, les rinçages du réseau de distribution, l’âge des conduites, les bris de
5
conduites, et certains facteurs environnementaux. Bien que de nombreuses tendances
intéressantes fussent notées, seulement quelques-unes donnèrent lieu à des différences
statistiquement significatives. Pour les systèmes s’approvisionnant en eau de surface et
pratiquant uniquement une chloration, la différence de moyenne portant sur le nombre
annuel de rinçages s’est avérée statistiquement significative. En plus, certains indicateurs
de la pression agricole sur le territoire des municipalités concernées apparurent
significativement corrélés avec les épisodes de coliformes.
Mots-clés : eau potable, qualité de l’eau, petits systèmes, épisodes de coliformes, systèmes
de distribution, Québec
1.1. Introduction In North America, small drinking water utilities (serving 10,000 or fewer people) have
more difficulty than larger utilities to comply with the increasingly stringent regulations on
distributed water quality. Indeed, small utilities have generally limited financial and
technical resources allowing them to remove contaminants from raw water, to adequately
operate the treatment and to implement management strategies to monitor and control water
quality in the distribution systems (Gouvernement du Québec 1997; AWWA 2000).
Among the important challenges for managers of small drinking water utilities are the
necessity of simultaneously ensuring adequate microorganism inactivation in the plant and
control in the distribution system and minimizing the formation of disinfection by-products
potentially carcinogenic, such as trihalomethanes (THMs). When surface waters are utilized
as raw water and chlorine is used as the principal disinfectant, such challenges become
more considerable. In the U.S., small water utilities using either surface or groundwater
will, in the coming months or years, have to comply with a number of new National
Primary Drinking Water Regulations such as stage 1 of the Disinfectants/DBP rule (for
residual disinfectant, maximum DBP levels and required treatment for organic carbon
removal), the long term 1 Enhanced Surface Water Treatment Rule (requirements for CT
calculations and filter monitoring/performance based on turbidity) and the Groundwater
6
Rule (requirement of sanitary surveys, raw water monitoring and treatment based
monitoring results) (USEPA 1998a; USEPA 1998b; USEPA 2000). In Canada, the federal
government has elaborated guidelines for drinking water quality which are not mandatory,
but that can be used by provinces to promulgate regulations for utilities within their
territory (Santé Canada 1996). Before 2000, only two Canadian provinces, Alberta and
Quebec (Gouvernement du Québec 1984), had promulgated mandatory regulations.
Following the water contamination event in the small community of Walkerton (Ontario)
during the summer of 2000, in which seven people died and more than 2,000 were taken ill,
some other Canadian provinces (British Columbia, Nova Scotia, Ontario) published new
regulations or updated their existing ones. This was the case of the Province of Quebec,
where, in June 2001, the government published new Quebec Drinking Water Regulations
(QDWR), whose application was mandatory for all utilities supplying water to more than
20 people (Gouvernement du Québec 2001). The 2001 QDWR constitutes a considerable
update of the first regulations promulgated in 1984. Small utilities in Quebec, specially
those using surface water, are particularly concerned by the 2001 QDWR, mainly because
new requirements or stringent standards are considered for turbidity of clear water,
microorganism inactivation (virus, Giardia and Cryptosporidium), bacterial monitoring,
minimum levels of residual chlorine and maximum annual average THM levels in the
distribution systems.
1.2. Small Utilities in Quebec In the Province of Quebec, there are about 1,000 municipal utilities that serve between 51
and 10,000 people. According to the Quebec Ministry of Environment (QME), small
utilities are known to have difficulties distributing water of good quality (Gouvernement du
Québec 1997). Among Quebec small municipal utilities, about 350 supply chlorinated
water with no previous physicochemical treatment to about 900,000 people (Gouvernement
du Québec 1997). The relative high concentrations of natural organic matter (NOM) in
most lakes, and the microbial pollution and high turbidity in southern Quebec streams, in
particular associated with agricultural drainage, will make compliance with the 2001
QDWR apparently very difficult for most of these utilities. In accordance with the quality
7
of the source water, particularly with the turbidity levels, most of these utilities will
probably have to modify their water treatment strategy in the coming years.
Even if the 2001 QDWR are currently in application, and although small utilities will be all
the more impacted by these regulations in terms of infrastructure and operation updating
requirements, there is currently very little knowledge about the characteristics of these
types of utilities, that is about their current state in terms of raw and distributed water
quality, treatment and disinfection practices, infrastructure and the strategies to maintain
the quality of water within the distribution system. In other words, at present there is no
portrait of small utilities in Quebec allowing identification of their state and their problems.
The aim of this paper is to establish a portrait of small drinking water utilities in Quebec
using a combination of data developed by the authors and public data from diverse sources.
Special emphasis will be placed on relating the state of the water quality (especially
microbiological) with the existing management practices. This portrait will allow
identification of their priorities and challenges for the upcoming years.
1.3. Source of Data To establish a portrait of Quebec’s small utilities, three main sources of data were used.
The first is a database managed by the QME, whose implementation is based on the routine
reports carried out by water utilities to comply with 1984 QDWR (Database 1). Database 1
contains mainly information on microbiological water quality for small utilities. The
second source of data was generated by the QME from sampling programs aiming to get
information about, among other things, organic substances in the distribution system
(Database 2). For the purpose of this research, Database 2 is comprised of THM data for
small utilities. The third source of data is a database developed by the authors following a
questionnaire-based survey directed to small utilities in Quebec (Database 3) in order to
obtain information about utility characteristics (treatment, operations, management,
maintenance, etc.). The fourth database comprised information on manure production in
Quebec municipalities. Other published and unpublished data developed by others is also
being considered in order to compare characteristics with those of other utilities.
8
1.3.1. Database 1 According to the 1984 QDWR, drinking water utilities in Quebec have had to test their
drinking water for specific parameters and send a report of results to the QME. The
frequency for parameter monitoring depends principally on the utility size (that is, the
population served). For small utilities, a very low monitoring frequency was required for
most inorganic and organic water quality parameters (in general, one or two samples per
year). These parameters include turbidity and residual chlorine, while total THMs were not
required to be monitored even if a 350 µg/L maximum contaminant level existed. However,
for microbiological quality control, from 1 to 10 samples per month (half of them taken at
distribution system extremity) were required to be analyzed (for utilities serving 201 to
10,000 people) in order to comply with regulations concerning total and fecal coliforms, the
only mandatory microbiological parameters according to 1984 QDWR (in June 2002, one
year after the promulgation of the 2001, higher monitoring frequencies and additional
microbiological parameters will be mandatory). According to this, data about total and fecal
coliform tests currently constitute the only historical information on microbiological water
quality based on utility compliance reports to QME. Consequently, database 1 consists of
this kind of data for a three-year period, 1997, 1998 and 1999. By considering this period, it
is possible to represent the recent trends and take into account variations from year to year.
Database 1 includes information on 927 utilities. The latter are municipal utilities that serve
from 201 to 10,000 people and which transmitted data on bacteriological control (i.e., fecal
and total coliforms) to QME from 1997 to 1999. This choice was based on the fact that in
accordance with the Quebec 1984 drinking water regulations (Gouvernement du Québec
1984), utilities serving from 51 to 200 people had to take only two samples per year for
bacteriological analyses.
1.3.2. Database 2 Since 1987, the QME has carried out sampling campaigns in selected Quebec water utilities
in order to investigate, among other things, the occurrence of organic compounds (called
9
the Surveillance Program) (Riopel 1992). In this program, special attention has been
focused on THM presence, particularly in vulnerable utilities, meaning those using surface
waters with moderate or high organic carbon content, during the summer period (generally
April to October). In general, within the Surveillance Program, samples for THMs were
collected following chlorination and/or within the distribution system (about 1.5 km from
the plant). Information generated from the Surveillance Program was used by the QME, for
example, to evaluate the technical and economical feasibility of updating the 350 µg/L
THM standard included in the 1984 QDWR (Vallée et al. 1993; Rousseau 1993; Tremblay
et al. 1995). This THM standard was used only as a guideline for utilities, since monitoring
requirements were not stipulated until the publication of the 2001 QDWR. Consequently,
the information on THM occurrence provided by such sampling programs constitutes the
only data available on a historical basis for Quebec water utilities. For the purpose of this
research, Database 2 consequently consists of THM data from the small utilities, which
took part at least once (all the year or only in summer) in the QME Surveillance Program
during 1997, 1998 and 1999. These utilities had also to be among the 927 utilities of
Database 1. As a result, 158 utilities were selected to form Database 2.
1.3.3. Database 3 Databases 1 and 2 provide information about two key parameters characterizing water
quality in distribution systems, coliform counts and THM. Because there is no database
containing information on characteristics for small water utilities in Quebec, it was decided
to conduct a questionnaire-based survey specifically for utilities serving from 201 to 10,000
people. Utilities selected for the survey were part of those included in Database 1. The
survey completed in early 2000 was based on a questionnaire (see Appendix A) sent by
mail to the principal manager/operator of each utility, asking for information about various
issues. These issues include general characteristics (type of water source, population
served, number of municipalities served, flowrates, etc.), water treatment procedures,
disinfection issues, the quality of treated and distributed water, distribution system
infrastructure and strategies to maintain water quality throughout the distribution system
(see Appendix A). To validate the questionnaire (test), fifteen utilities were pre-selected at
10
random and asked to respond. Some minor adjustments were made, based on their
responses and comments. The questionnaire was then sent to about 25 percent of the 927
above-mentioned utilities (precisely, to 247 utilities). 114 small utilities returned the
completed questionnaire, resulting in a response rate of about 46 percent. For specific
questions within the questionnaire, however, the response rate varied considerably.
1.3.4. Database 4 In many municipalities of the Province of Quebec, agricultural pollution is of great
concern. In order to control this threat to the environment and regulate the issue, the QME
developed a database comprising data related to manure production in each municipality.
For the purpose of the present study, a subsidiary database was built up from data of
municipalities corresponding to the 114 responding utilities.
1.3.5. Other published data Results obtained from databases 1, 2 and 3 will allow the establishment of a portrait of
small utilities in Quebec. Some particular characteristics of this portrait will be in addition
compared to characteristics of small and larger utilities of the US. Basically, comparisons
will be carried out using information collected from the Water Utility Database (now
known as ‘Water:\Stats’, AWWA 1998), which is a survey conducted in 1996 essentially
among large and medium-size utilities in the U.S (i.e., those serving 10,000 or more
people) and from the results of the disinfection practices survey for U.S. small utilities
(serving 10,000 or fewer people) conducted in 1998 (AWWA 2000).
1.4. Portrait of Small Utilities The portrait of small Quebec utilities was established based on all this information. The
portrait comprises mainly the state of the microbiological water quality (Database 1), the
state of the physicochemical water quality (Databases 2 and 3), an overview of
management strategies which may influence water quality in the distribution system
11
(Database 3), the relationships existing between microbiological quality and some
management strategies (Databases 1 and 3), and the relationships between microbiological
quality and agricultural (environmental) factors (Databases 1 and 4).
1.4.1. General characteristics and physicochemical water quality Most of the utilities where staff completed and returned the survey questionnaire operated
very small utilities: 37 percent served from 201 to 1,000; 57 percent served from 1,001 to
5,000 and only 6 percent served from 5,001 to 10,000 people. Indeed, the survey response
rate for utilities serving from 5,001 to 10,000 was found to be considerably lower than the
response rate for the rest of the utilities (only 30.4 percent, while those serving from 201 to
1,000 and from 1,001 to 5,000 people had a response rate of 45.2 and 49.6 percent,
respectively).
The majority of the surveyed utilities use surface water (i.e., water from lakes, rivers and
streams, or groundwater directly influenced by surface water) (Table 1.1). The average
served flowrate of distributed water was found to be about 2600 m3 per day according to 58
utilities who provided this information. Concerning the parameters of water quality, the
response rate was relatively low (Table 1.2). This is understandable, considering that in
1984 QDWR, requirements for monitoring physicochemical parameters were weak. Thus,
only data for parameters for which the response rate is above 15 percent are presented
(Figure 1.1). From the utilities providing quality parameter data, about 55 percent indicated
the turbidity of their raw water to be lower than 1 NTU and about 28 percent to be higher
than 5 UNT (Figure 1.1-a). All groundwater utilities providing data (except two) have
indicated turbidity levels lower than 1 UNT, whereas about one third of surface water
utilities indicated average raw water turbidity higher than 5 UNT. It is important to mention
that these turbidity values are average values, and that there may be large differences
between the average and the maximum values encountered. These maximum turbidity
values, which are not documented in this paper, are often the main source of problems.
Only one third of utilities indicated the true colour to be lower than 15 TCU, whereas about
the same proportion indicated true colour higher than 50 TCU (Figure 1.1-b). Distribution
12
Table 1.1. Water source, treatment, and disinfectant type for the surveyed utilities
Characteristics Number of respondents (n)
Response rate (out of 114 utilities)
Surface water 70 61.4 Source water Groundwater 44 38.6
No treatment 28 24.6 Chlorination alone 71 62.3 Treatment Treatment 15 13.1
None 28 24.6 Cl2 41 36.0 NaClO 42 36.8
Disinfectant
Cl2 and NaClO 3
2.6
Table 1.2. Water quality and operational parameters for the surveyed utilities Parameters Number of respondents
(n) Response rate (out of 114 utilities)
winter 32 28.1 raw water summer 30
26.3
winter 28 24.6 Turbidity
treated water summer 27
23.7
winter 20 17.5 raw water summer 20
17.5
winter 18 15.8 Colour
treated water summer 18
15.8
winter 51 44.7 Chlorine dose (operational) summer 51 44.7
winter 24 21.1 treated water summer 24
21.1
winter 19 16.7 Free chlorine residual
distributed water summer 21
18.4
13
(32)
(31)
(28)(27)
0
3
6
9
12
15
w inter summer w inter summer
Raw water Treated water
Turb
idity
, NTU
(51)
(51)
0
1
2
3
4
5
w inter Summer
Season
Chl
orin
e do
se, m
g/L
(24) (24)
(19)
(21)
0
0.3
0.6
0.9
1.2
1.5
w inter summer w inter summer
Treated water Distributed water
Free
chl
orin
e, m
g/L
(18)(18)
(20)
(21)
0
30
60
90
120
150
w inter summer w inter summer
Raw water Treated water
True
col
or, T
CU
a. b.
c. d.
Figure 1.1. Distribution of water quality parameters among responding utilities: a, turbidity; b, colour; c, chlorine dose; and d, free chlorine residual. In brackets, number of utilities; lower bar, C10; upper bar, C90; cross, mean
14
of turbidity and colour values indicated by respondents was significantly higher in summer
than in winter. A reasonable explanation for this is the presence of snow/ice layers in
Southern Quebec surface watersheds during about four months of winter, which naturally
protect sources of water from watershed runoff; another possible explanation is that
because of high summer water temperatures, biological activity, planktonic in particular, is
much higher.
Very few surveyed utilities indicated the use of a physicochemical treatment to remove
turbidity, colour and organic carbon (Table 1.1). Practically all those utilities (with one
exception) indicated the use of surface water as a water source. However, only 20 percent
of utilities using surface water apply other treatment before chlorination (flocculation,
settling, filtration). This is extremely different from the results obtained by others in the
U.S., where 94 percent of surveyed small utilities indicated the use of at least filtration
before disinfection (AWWA 2000), which is a direct consequence of the U.S National
Primary Drinking Water Regulations (USEPA 1989). A more surprising result is that about
one fourth of small Quebec utilities do not apply any treatment or disinfection (even for
residual disinfectant maintenance) before delivering water into the distribution system.
However, practically all of these utilities use groundwater as a raw water source (only one
utility indicated using surface water without any treatment). All utilities that disinfect water
before distribution use chlorine-based disinfectant, the same proportion with gas chlorine
and with calcium/sodium hypochlorite. The use of hypochlorite as chlorine-based
disinfectant appeared a little more widespread in small Quebec utilities (in 50 percent of
utilities with disinfection) than in small U.S. utilities (34 percent) (AWWA 2000).
Applied chlorine doses before water distribution appeared to be higher in summer than in
winter (Figure 1.1-c). This is not consistent with the fact that chlorine efficacy for micro-
organism inactivation is higher in warm waters than in cold ones. However, these data
appear realistic, considering that chlorine is the unique disinfectant applied in the surveyed
utilities, that is, it is utilized simultaneously for ensuring inactivation and to maintain
residual chlorine levels in the distribution system. For the latter purpose, higher chlorine
doses are generally applied in summer to counterbalance the rapid decay of residual
15
chlorine associated with higher water temperatures. These results are comparable to those
of research programs undertaken by the authors with medium and large drinking water
utilities of Quebec (Milot et al. 2000; Rodriguez et al. 2000; Rodriguez et al. 2001). It was
also observed that average dose levels for small Quebec utilities were higher among
utilities not using treatment (1.44 mg/L on average) than among those using treatment (1.12
mg/L on average). The higher doses were indicated by utilities that chlorinate surface
waters without any previous physicochemical treatment (on average, 1.66 mg/L).
Concerning the physicochemical quality in treated water (before distribution), more than 80
percent of responding utilities indicated producing drinking water with less than 1 UNT and
about 50 percent with less than 0.5 UNT, which is the standard of the Quebec 2001 QDWR
(Figure 1.1-a). A surprising result is that no responding utility indicated producing treated
water with turbidity levels higher than 5 UNT, which was the maximum acceptable level in
the 1984 QDWR. Average values for true colour indicated by respondents were lower than
5 TCU in more than 75 percent of the utilities (Figure 1.1-b). Also, according to the
respondents, levels of both turbidity and colour in the distribution system were comparable
to levels of these parameters in treated water. It was observed that utilities using treatment
(all with surface water, except for one) had the best quality according to both parameters
(average values for turbidity and colour in treated water equal 0.2 NTU and 1.2 TCU,
respectively), followed by groundwater utilities with or without treatment (average values
for turbidity and colour in treated water equal 0.7 NTU and 4.8 TCU, respectively).
Utilities applying direct chlorination to surface water had the lowest physicochemical water
quality (average values for turbidity and colour in treated water equal 0.7 NTU and 19.3
TCU, respectively). In the case of free residual chlorine in the water leaving the plant
(following chlorination), practically all utilities reported more than 0.2 mg/L (which was
the standard included in the 1984 QDWR), with higher values in summer than in winter
(Figure 1.1-d). Moreover, all utilities reported having detectable levels for this parameter at
the extremity of the distribution system: about 90 percent of the surveyed utilities reported
levels for this parameter as being above 0.1 mg/L, whereas more than half reported values
above 0.2 mg/L. These reported values appear higher than expected (especially in summer,
16
when chlorine demand is high), considering that all utilities reported maximum residence
time of water higher than 12 hours.
Considering the fact that a new standard for THMs is included in the Quebec 2001 QDWR
(80 µg/L based on a quarterly annual average of samples taken at the extremity of the
distribution system), it was considered appropriate to create a portrait of concentrations of
this parameter in small Quebec utilities. Because only about 2 percent of responding
utilities provided data about THMs, the portrait for these parameters was made on the basis
of information included in Database 2 (Figure 1.2-a and Figure 1.2-b). According to results,
in more than 30 percent of the utilities THM levels in the distribution system (that is, 1.5
km from the plant) were below 50 µg/L, and in more than 55 percent below 80 µg/L.
Considering that all available data were generated from samples taken between April and
October, it is probable that the annual average concentration of THMs for these utilities are
in reality further below the THM values shown in Figure 1.2. This allows us to infer that, if
for such utilities sample location represents the extremity of the distribution system, the
majority of utilities would comply with the 2001 QDWR. According to Figure 1.2, utilities
more susceptible to not complying with the THM standard are those that directly chlorinate
surface waters (without any previous treatment). This is understandable, considering that
THM precursors contained in raw waters (natural organic matter) are not removed by a
physicochemical treatment in these utilities (mean TOC values are 3.22 mg/L, 3.81 mg/L,
and 3.10 mg/L for groundwater plus chlorination alone, surface water plus chlorination
alone and surface water plus treatment, respectively).
17
(10)(121)
(26)
0
50
100
150
200
GW+chlorination SW+chlorination SW+treatment
Tota
l TH
Ms,
ug/
l
(n = 64) (n = 79)
(n = 15)
0
50
100
150
200
201-1000 1001-5000 5001-10000
System size (population served)
Tota
l TH
Ms,
ug/
l
a. b.
Figure 1.2. Average total THM concentrations according to: a, source water and treatment; b, utility size. In brackets, number of utilities; lower bar, C10; upper bar, C90; cross, mean. GW denotes Groundwater; SW denotes Surface Water.
18
1.4.2. Portrait of the microbiological water quality To establish the portrait of microbiological water quality of the treated and the distributed
water of small Quebec utilities, two indicators were built up using the information
concerning total coliform (TC) and fecal coliform (FC) counts of database 1. To distinguish
water samples considered microbiologically contaminated from those not contaminated, TC
and FC data were initially converted in a dummy variable, indicating negative samples for
TC (less than 10 organisms/100 mL, the maximum that does not systematically infringe
upon the Quebec QDWR) and positive samples for TC (more than 10 organisms/100 mL).
As for FC, any count different from zero was considered positive. From this new variable,
two indicators were created. The first is called coliform episode and indicates one or a set
of coliform positive samples occurring in a given distribution system during the three-year
period (1997-1999), separated by at least 15 days from any other coliform positive sample
in the same system. Such a criterion allows us to consider as a unique episode a number of
positive samples occurring in a short period of time, and that have probably been associated
with the same cause. This criterion also allows us not to consider as independent episodes
the number of positive samples encountered following the intensive sampling program that
generally follows the detection of a first positive sample for TC or FC (sampling carried out
in the days following the laboratory results). The second indicator is called problematic
utility and designates a utility that registered one or more coliform episodes in at least two
of the three reference years. Consequently, utilities that registered no coliform episode, or
had episodes in only one of the above-mentioned three years, were called nonproblematic
utilities. This indicator allows distinguishing utilities with recurrent coliform occurrences
from those with rare or no such occurrences.
Using data about total and fecal coliform of database 1 and the two indicators described
above, a portrait of water quality was built up (Table 1.3.). Judging by data of Table 1.3., it
would be hard to say that the respondents’ sample is representative of the population.
However, since emphasis, as stated above, is put on relating the microbiological water
quality with the existing management practices, the responding sample representativeness
19
Table 1.3. Portrait of the coliform appearances in investigated small utilities (1997 through 1999)
Target utilities (n = 927)
Responding utilities (n = 114)
Percent out of concerned utilities total ⎯ 12
Percent out of total population served ⎯ 14
Average population served 1807 2062
200 – 1000 * 2.7 4.0 1001 – 5000 1.3 2.0
Percent of coliform positive samples in summer (April through September) 5001 - 10000 0.8 0.9
200 – 1000 1.3 1.1 1001 – 5000 0.4 0.5
Percent of coliform positive samples in winter (October through March) 5001 - 10000 0.2 0.3
200 – 1000 55 79 1001 – 5000 50 66 Percent of utilities with at least
1 coliform episode 5001 - 10000 42 57 **
200 – 1000 2.6 3.2 1001 – 5000 2.4 2.6
Average number of coliform episodes for utilities with at least 1 episode 5001 - 10000 2.2 3.7
200-1000 27 55 1001-5000 21 34 Percent of problematic utilities
out of total number of utilities 5001-1000 16 57 **
200 – 1000 50 70 1001 – 5000 42 51
Percent of problematic utilities among those with at least 1 coliform episode 5001 - 10000 37 100 **
200 – 1000 3.8 3.9 1001 – 5000 3.9 3.8 Average number of episodes
for problematic utilities 5001 - 10000 3.9
3.7 * Population served ** Such abnormally high values are due to a very small total for this group (7 utilities only, compared to 83 among the 927). may be of less concern, the central issue being rather to look for factors that may explain
coliform appearances (i.e., episodes) in studied distribution systems. Moreover, even
assuming that the survey sample (n = 247) is representative of the population of utilities (n
= 927), it would be impossible to ensure that the respondents’ sample be representative,
20
since one could have no control on the ultimate decision of a surveyed utility manager to
respond or not. Information in Table 1.3. shows that even though the average percentage of
coliform positive samples appears relatively low (about 1 percent), a high number of
utilities have experienced microbiological water quality problems. According to the period
under study, half of small Quebec utilities have experienced one or more coliform episodes.
Among these utilities, the average number of episodes was about 2.4, whereas one fifth of
utilities experienced more than three episodes (only 1 percent experienced all of them in
one year). About 25 percent of all are problematic utilities, that is, having experienced
recurrent microbiological problems in the distributed water. It is also observed that the
portrait for microbiological water quality varies considerably according to the utility size.
Indeed, more than 2 percent of all water samples collected in very small utilities (serving
between 201 and 1,000 people) during the period under investigation were found coliform
positive, this percentage being significantly higher during summer periods. However, no
significant differences were observed between samples taken in the distribution system
extremities in comparison with those taken in other locations (data not shown in Table
1.3.), which is a surprising result considering that it is well known that extremities
constitute favourable locations for biofilm development and locations at which levels of
residual chlorine are the lowest. Differences between utilities according to their size are
also observable when examining both indicators, coliform episodes and problematic
utilities, but such differences appeared less important (in terms of relative value) than in the
case when only the percentage of coliform positive samples are examined. Such a result
means that in very small utilities, a single coliform episode is represented by a higher
number of positive TC or FC samples than in larger utilities. This suggests that in larger
utilities (specially those serving between 5,000 and 10,000 persons), coliform episodes are
relatively short, probably related to the shorter time required in these utilities (having
generally more human and technical resources) for identifying the source of micro-
organisms and the more rapid and efficient measures taken to resolve the problem.
Differences in microbiological water quality according to the utility size appear directly
related to the source of water and the treatment process applied (Table 1.4.). Indeed,
21
Table 1.4. Distribution of population served and coliform episodes according to water source and treatment types (for responding utilities)
Type of treatment No treatment * Chlorination alone Treatment ** Groundwater
n = 27 Surface water
n = 55 Groundwater
n = 16 Surface water
n = 14
Percent out of total number of respondents 24 48 14 12
Percent out of population served by responding utilities 17 46 17 19
Average population served 1478 1965 2504 3242
Percent of utilities with at least 1 coliform episode 59 82 75 43
Average number of episodes for utilities with at least 1 episode 2.6 3.2 2.6 2.7
Percent of problematic utilities 33 53 37 29
Average number of episodes for problematic utilities 3.2 4.2 3.5 3.5
* There was only one utility which used surface water and no treatment; that case was ignored. ** So was the sole utility that used groundwater and treatment. utilities using physicochemical treatment before chlorination, which are those that serve
larger populations on average, have experienced significantly fewer problems of
microbiological water quality in the distribution system than utilities using chlorination
alone (from surface or groundwater sources) or utilities that do not use treatment at all.
Utilities that encountered the most important and frequent difficulties of microbiological
water quality in the distribution system are those that directly chlorinate surface waters.
One can notice from the analysis made earlier that the same group of utilities (which
represent one third of small Quebec utilities) are those that also have the highest values of
THMs. Finally, this group is also the one that encompasses the highest percentage of
22
utilities that experienced at least one coliform episode, the highest percentage of
problematic utilities, and the highest average number of episodes. Generally speaking, the
coliform occurrences appear more recurrent for utilities supplied by surface sources,
confirming the high vulnerability to microbial intrusion for such utilities.
1.4.3. Strategies for maintaining microbiological water quality in the distribution system
Small utilities were also asked during the survey for information about characteristics of
their infrastructure and the routine and long-term strategies to manage water quality in the
distribution system. Issues investigated, such as rechlorination and pipe characteristics and
maintenance (age, material, break rate, corrosion strategies and pipe cleaning strategies),
can directly or indirectly affect the water quality within the distribution system. Table 1.5.
presents the information obtained for some of these issues.
Table 1.5. Survey responses for specific distribution system characteristics (pipe age, pipe material, main breaks, and system flushings)
Percentiles Characteristics Respondents
(n) Minimum
C10 C50 C90 Maximum Mean
Pipe age, years 104 2.00 20.0 33.5 60.0 100 36.2
Cast-iron 100 0.00 2.20 75.0 100 100 62.8 PVC 100 0.00 0.00 20.0 75.0 100 27.8 Percent of total
pipe material others 100 0.00 0.00 0.00 30.9 100 9.52
Number of main breaks/km/year 95 0.01 0.07 0.22 0.62 1.50 0.29
Number of flushings per year
104 1.00 1.00 2.00 3.00
12 1.93
1.4.3.1. Rechlorination practices Residual chlorine is recognized to be an indicator of water quality in a distribution system,
particularly because it can reduce the risk of microbial regrowth (Sobsey et al. 1993;
23
Sérodes et al. 1998; Haas 1999; LeChevallier 1999). It is noteworthy however that the issue
of maintaining a residual is not clear cut, and has generated some controversy in recent
years. In this respect, a number of authors consider that the necessity of chlorine residual
maintenance is arguable due to its poor efficacy to inactivate waterborne pathogens in
drinking water distribution systems (Payment 1999; van der Kooij et al. 1999). Because
chlorine reacts with organic and inorganic compounds when added to water in the plant
before distribution, residual chlorine levels can rapidly decay and even disappear at
extremities, especially for utilities with extensive distribution systems and long retention
times (Kirmeyer et al. 1993; Reiber 1993). Rechlorination of water within the distribution
system may counterbalance initial chlorine decay. According to small Quebec utility
respondents, only a small percentage of utilities (about 10 percent), particularly the larger
ones (in terms of both population served and pipeline length), use rechlorination facilities
within the distribution system to maintain sufficient residual chlorine levels. However, it
was found that the average residual chlorine for small responding utilities using
rechlorination is practically the same in winter and significantly lower in summer than
average residual for utilities not practicing rechlorination. It is interesting to observe that
almost all responding utilities that rechlorinate are surface water utilities that do not use any
treatment before chlorination. This is probably due to the fact that the chlorine demand
following the dose application is higher for those utilities because of the lower quality of
water. Thus, to compensate for high initial chlorine demand, rechlorination generally
appears to be a good strategy to ensure minimal levels of residual chlorine and minimize
the probability for bacterial regrowth.
1.4.3.2. Pipe characteristics The issue of water main assessment and associated research needs is well documented
(AWWA 1994; Rajani et al. 1995; Kitaura et al. 1996; Makar 2000; Rajani et al. 2000).
Aging distribution system pipes, in particular those made of iron-based material, can cause
water quality deterioration within the distribution system, especially through corrosion. In
addition to favouring precipitation of metal ions, which can cause coloured water, pipe
corrosion may favour the formation of tubercles within which a biological film can form or
24
cause breaks in the main, both aspects being favourable conditions for deterioration of
microbiological water quality (LeChevallier et al. 1990). Distribution system pipes of the
responding small utilities appeared, surprisingly, relatively older in comparison to medium
and large utilities in Quebec. Indeed, an average of about 57 percent of pipes of small
Quebec utilities are, according to respondents, 35 years old or less, compared to an average
of 65 percent of medium and large Quebec utilities (Villeneuve et al. 1998; Fougères et al.
1998), and 24 percent of responding utility pipes are 20 years or less, compared to 34
percent for medium and large utilities. However, only a minority (about 30 percent) of
responding small Quebec utilities acknowledged that their pipes suffered from corrosion
problems, and only a third of those utilities implemented corrosion control strategies
(generally by ensuring a relatively high pH by adding calcium or phosphate). This result
appeared surprising, considering that on average, 63 percent of the distribution system
pipes are made of cast iron (on average, 28 percent made of PVC).
Concerning the infrastructure of the distribution system, small Quebec utilities reported an
average rate of breaks which can be considered acceptable according to McDonald et al.
1997, who judged that a main break rate can be considered abnormally high when it
exceeds 40/100km/year (78 percent have had this many or less). However, it is observed
that only half the utilities reported a break rate that is lower than 25/100km/year, which is
the average for distribution systems of Ontario towns, according to the Ontario Sewer and
Watermain Contractors Association (CMCH 1992). The average break rate indicated by
responding utilities (about 29/100km/year) is also more than double the one for US towns
distribution systems, that is, about 13/100km/year (AWWA 1994). Results indicate that the
average main break rate for responding utilities more than 50 years old (30/100km/year) is
slightly lower than the one for those with ages ranging from 31 through 50 years
(32/100km/year), whereas, as expected, the younger utilities (30 years old or less)
experienced much fewer main breaks (27/100km/year). The average for all utilities more
than 30 years old is also about 32/100km/year. Surprisingly, the average main break rate
for utilities which suffer from corrosion problems is slightly lower than the one for those
not experiencing such problems: 29/100km/year and 30/100km/year, respectively.
Moreover, the mean age for utilities experiencing corrosion (about 41 years) is higher than
25
the one for utilities without corrosion (about 35 years). Utilities applying corrosion control
strategies had significantly fewer breaks (24/100km/year) than those, which have not
developed such strategies (33/100km/year), but the former are younger than the latter
(mean ages of 39 and 44 years, respectively). So, it seems that all of this is tied to pipe age,
hence the importance of an adequate pipe replacement policy. Besides, according to
Villeneuve et al. 1998, only about one percent of the total pipe mileage of Quebec utilities
is replaced every year. This replacement rate may appear too low, judging by the above-
mentioned (observed) breakage rates.
One important strategy for maintenance of water quality in distribution systems is to carry
out periodic flushing in order to take out different natures of deposits in the pipe wall
internal surface. Flushing is considered an efficient strategy; particularly to take out biofilm
and corrosion tubercles which both favour microbiological deterioration within the
distribution system (Antoun et al. 1999; Duranceau et al. 1999). All small Quebec utilities
reported flushing the distribution system at least once each year and more than half reported
at least 2 flushings. Most of the utilities carrying out only one flushing usually made it later
in summer or in fall. According to Antoun et al. 1999, this may be a good management
strategy, because it ensures pipeline cleaning after the period within which biofilm
development is most proliferate. This similarity appears surprising, but encouraging,
considering that generally speaking, larger utilities possess higher financial capacities for
maintenance of infrastructure. However, it was also observed that very small Quebec water
utilities (those serving less than 1,000 persons) carry out as many flushings as larger ones
(on average 2 per year).
1.4.4. Relationships between management strategies and microbiological water quality
The portrait of microbiological water quality was also investigated in accordance with the
management strategies mentioned earlier. It was developed principally by combining the
information contained in Databases 1 and 3. Table 1.6. to Table 1.9. present the results
concerning these analyses. Particular attention was paid to the more vulnerable utilities,
26
meaning those which directly chlorinate surface waters. According to results, utilities not
having water quality problems generally apply lower chlorine doses, during both winter and
summer (Table 1.6.). These results appear surprising, because it is expected that higher
chlorine doses ensure higher microbial inactivation and higher free chlorine residual
concentration and, thus, greater protection from microbiological degradation of water
quality in the distribution system. These results suggest that in small utilities where there
exist recurrent microbiological problems, managers use higher chlorine doses as a
corrective measure, but that such strategy does not necessarily prevent or reduce these
problems. Certainly, increasing the applied chlorine dose does not necessarily ensure an
increase of residual chlorine in every location of the distribution system, and thus does not
necessarily ensure an improvement of microbiological water quality, since many other
factors can be related to coliform regrowth in drinking water (LeChevallier 1996).
According to Table 1.7., utilities with recurrent water quality problems practice less
flushings on average of their distribution system than those which do not have such
problems. Even if the median for the number of annual flushings is similar for utilities with
and without recurrent problems, it appears that utilities which make two or more flushings
per year have better results within a perspective of microbiological water quality than those
which make only one. This trend was much stronger and statistically significant (P < 0.1)
for utilities which directly chlorinate surface waters. The results in Table 1.7. suggest that
generally, flushing has real positive impacts on distribution system water quality.
As mentioned earlier, it is well known that aging distribution systems may favour corrosion
and biofilm development in the pipe wall, thereby possibly affecting water quality.
However, according to Table 1.8., no significant differences in microbiological water
quality were observed in small Quebec utilities according to the age of the distribution
system, even if the age variations of the utilities under study are important (as presented
earlier in Table 1.5.). A possible explanation for this is that the average age of the
distribution system pipes is not necessarily representative of the entire utility (that is, very
large age pipe variations can exist in a single utility), because it is very probable that some
27
Table 1.6. Observed relationship between the chlorine dose (mg/L) and the utility microbiological status All responding utilities
(N = 114)
Surface water utilities using chlorination alone
( N = 55)
n
Median of dose
Mean dose
P
n
Median of dose
Mean dose
P
Utilities with no episode 14 0.55 0.95 5 0.50 1.34 Utilities ≥ 1 episode 37 1.00 1.22 0.43 24 1.50 1.41 0.94
Nonproblematic utilities 33 1.00 1.11 18 1.15 1.38 Winter
Problematic utilities 18 1.25 1.21 0.70 11 1.50 1.41 0.94
Utilities with no episode 14 0.90 1.23 5 0.80 1.50 Utilities ≥ 1 episode 37 1.50 1.74 0.22 25 2.00 2.01 0.62
Nonproblematic utilities 32 1.20 1.56 18 1.35 1.90 Summer
Problematic utilities 19 1.50 1.67 0.76 12 2.25 1.95 0.92
P : significance level of the means test
28
Table 1.7. Observed relationship between distribution system flushings and the utility microbiological status
All responding utilities
(N = 114)
Surface water utilities using chlorination alone
( N = 55)
n Median of flushings
Mean of flushings
P
n
Median of flushings
Mean of flushings
P
Utilities with no episode 30 2.00 2.20 9 2.00 3.78 Utilities ≥ 1 episode 74 2.00 1.82 0.29
43 2.00 1.84 0.005
Nonproblematic utilities 59 2.00 2.12 24 2.00 2.58 Problematic utilities 45 2.00 1.69 0.14
28 2.00 1.82 0.16
P : significance level of the means test Table 1.8. Observed relationship between distribution pipe age and the utility microbiological status
All responding utilities
(N = 114)
Surface water utilities using chlorination alone
( N = 55)
n Median of age
Mean age P
n
Median of age
Mean age P
Utilities with no episode 32 31.5 35.0 10 22.0 27.2 Utilities ≥ 1 episode 72 34.0 36.8 0.65 42 32.0 36.6 0.20
Nonproblematic utilities 60 30.0 34.9 25 25.0 32.5 Problematic utilities 44 35.0 38.0 0.37 27 34.0 36.9 0.39
P : significance level of the means test
29
Table 1.9. Observed relationship between distribution main breaks and the utility microbiological status
All responding utilities
(N = 114)
Surface water utilities using chlorination alone
( N = 55)
n Median of
breaks Mean of breaks
P
n
Median of breaks
Mean of breaks
P
Utilities with no episode 28 0.20 0.31 8 0.24 0.43 Utilities ≥ 1 episode 67 0.25 0.29
0.82 39 0.17 0.23
0.06
Nonproblematic utilities 54 0.23 0.30 22 0.17 0.31 Problematic utilities 41 0.22 0.28
0.67 25 0.17 0.23
0.33
P : significance level of the means test
30
pipes have never been replaced, while others could have been replaced very recently.
However, no information about pipe replacement rate was available from Database 3.
Finally, even if pipe breaks are known to be a possible source of microbial intrusion in
distribution systems, no significant differences of the annual breakage rate were observed
between utilities having water quality problems and those not having them (Table 1.9.).
However, a surprising result is observed for utilities that directly chlorinate surface waters.
Among these utilities, those not having microbiological problems at all (that is any episode
at all) have significantly higher pipe breakage rates (for both mean and median values) than
those that do have quality problems. In addition, the average pipe breakage rate in these
utilities appeared higher than the maximum acceptable recommended (Ontario, MacDonald
1994). Many possible explanations may be put forward to explain this apparently illogical
result. First, it appears that extreme breakage statistics are more frequent among utilities
experiencing 29 breaks/100km/year (the overall average value) or fewer. Second, the
relative weight of utilities practicing chlorination alone (which were found to be more often
problematic than all others) is bigger among this same group. Third, the age, type and
corrodibility of pipe material may also be involved; for instance, for utilities having less
than 50 percent of their pipelines made of PVC, the average number of main breaks is
much higher than that for utilities with more than 50 percent PVC (32 breaks/100km/year
and 22 breaks/100km/year, respectively).
1.4.5. Relationships between agricultural land use and microbiological water quality
As part of Quebec’s recent regulations about agricultural pollution, and in order to control
cattle breeding expansion in locations where agriculture is already too intensive, all
municipalities of the province have been designated a manure status (as specified in data
received from QME). Such a status is a function of the intensity of agriculture pressure on
their territory (soils). This factor is measured by the annual balance of phosphorus in terms
of kilograms of phosphorous (P2O5) per hectare. It considers total manure production
within the municipality, the nutrient requirements of crops and the cultivated area. When
31
the annual balance is more than 20 kg P2O5/ha/year, the authorities consider the
corresponding municipality as being in manure surplus. However, for a number of
municipalities, even a zero annual balance is considered an administrative surplus, because
they are situated in watersheds with already significant phosphorus excess. Even if such an
annual balance was not calculated based on watershed limits but rather on municipal limits,
it can be used as an indicator of the susceptibility of surface waters to be contaminated by
surface or subsurface runoff. For the purpose of this study, information about the manure
status had been considered under four variables in order to associate it with water quality in
small utilities. These variables are: zone with/without manure production, zone
administratively/not administratively in a surplus situation, annual manure balance less or
equal to/more than 0 kg P2O5/ha, and surplus of phosphorus less/equal to or more than 20
kg P2O5/ha/year. The impact of each of these factors on microbiological water quality is
analyzed in Table 1.10. The results indicate that on the whole, utilities located in zones
with high agricultural pressure experienced more water quality problems (related to total or
fecal coliforms). The impact of agricultural pressure on water quality appeared significant
for the more vulnerable utilities, that is, those chlorinating surface water without any
previous treatment. Indeed, two of the four manure-related variables, (i.e., “administratively
in phosphorus surplus” and “phosphorus annual balance”) were found to be significantly
correlated with the variable “number of coliform episodes”. This suggests that future
controlling of cattle breeding expansion will have a considerable effect on small vulnerable
utilities.
1.4.6. Multivariate analyses In order to evaluate interactions between variables or potential collective impacts of the
studied management strategies on microbiological water quality, multivariate analyses were
carried out. Three variables: “problematic/nonproblematic”, “episodes/no episode”, and
“number of episodes” had to be explained. Because the first two are dichotomous, a binary
stepwise logistic regression analysis was performed to search for factors explaining them.
32
Table 1.10. Observed relationship between agricultural pressure indicators and microbiological characteristics of utilities
All responding utilities
(N = 114)
Surface water utilities using chlorination alone
( N = 55)
n Utilities ≥ 1 episode,
%
Problematic utilities, %
Average episode number
P n Utilities ≥ 1 episode,
%
Problematic utilities, %
Average episode number
P
Zone with manure production 93 72 44 2.13 43 84 53 2.65 Zone without manure production 21 62 38 1.71 0.427 12 75 50 2.33 0.691
Zone administratively in surplus 23 65 43 2.39 9 100 78 4.67 Zone administratively not in surplus 91 71 43 1.97 0.471 46 78 48 2.17 0.020
Manure balance > 0 kg P2O5/ha/year 31 68 48 2.29 16 87 69 3.37 Manure balance ≤ 0 kg P2O5/ha/year 83 71 41 1.96 0.501 39 79 46 2.26 0.141
Surplus ≥ 20 kg P2O5/ha/year 16 69 37 2.06 6 100 67 3.83 Surplus < 20 kg P2O5/ha/year 98 70 44 2.05 0.984 49 80 51 2.43 0.208
P : significance level of the means test
33
For the continuous variable (“number of episodes”), a linear regression analysis was used.
First, analyses were carried out for all responding utilities, and then for respondents using
surface water and chlorination alone. When all respondents are considered, the only
variable that exhibits a significant relationship with the three specified dependent variables
is the treatment type. This is obvious, and needs no particular explanation. So, no
multivariate model emerges for the whole set of respondents. As for surface water utilities
using chlorination alone, one model comes out and indicates that 33 percent of the
explained variance related to the dichotomous variable “problematic/nonproblematic” is
tied to variables “phosphorus annual balance” and “phosphorus surplus more than 20 kg
P2O5/ha/year”, with the model being significant at the 1 percent (0.01) level (logistic
regression analysis: χ2 = 11.9; R2 = 0.33; P = 0.003). This suggests that the fact that a
surface water utility with chlorination alone is either problematic or nonproblematic with
regard to microbiological quality (total or fecal coliforms) is relatively easy to explain by
the agricultural land use of the municipality where the utility is located. Such an indication
seems easily explicable, since it is well known that cattle feces and piggery effluents
contain great quantities of bacteria and parasites that may eventually find their way into
water springs by means of agricultural runoff or infiltration into ground water.
1.5. Conclusions This research has documented some important characteristics of small Quebec drinking
water utilities. First of all, one notes that even though all of these utilities are called small
utilities, and are supposed to have very comparable financial and technical resources, the
quality of their distributed water may vary considerably. Actually, three groups of utilities
emerged during this study: first, utilities which never experienced problems with
microbiological water quality during the reference three-year period (1997 through 1999);
second, utilities that occasionally encountered difficulties complying with drinking water
regulations relating to total coliforms; and, third, utilities which very often infringed upon
quality standards. The first two groups can be considered as distributing relatively safe
water to their customers. The last group obviously consists of utilities that have major
problems.
34
Most of the latter are utilities that directly chlorinate surface waters without any other
treatment. These problematic utilities may need to acquire a treatment facility, especially
considering the new and much more stringent QDWR promulgated by the Quebec
government in June 2001. These utilities, unable to comply with coliform standards, will
now have to cope with parasites, viruses, and monitoring of trihalomethanes, to name but a
few. It is hard to believe that small problematic utilities will overcome such obstacles,
without managing, at least in a filtration facility, to reduce NOM content in their distributed
water. In any case, they will have to apply filtration in a relatively near future, since new
QDWR (that will come into force in June 2002, except for a few recently amended clauses
including filtration, the effective date for the latter being postponed until June 2005 for
utilities serving fewer than 50,000 people, and until June 2007 for those serving 50,000 or
more people) make filtration practically inevitable for all Quebec surface water utilities.
Concerning infrastructure and water quality maintenance, small utilities appeared to be
aging, compared to medium-size and large ones. This may be attributable to the fact that
most of medium-size and large utilities pertain to numerous relatively young suburbs that
grew all around big Quebec metropolitan areas like Montreal or Quebec City, some 40 to
50 years ago. Among distribution water quality management strategies analyzed, some
interesting trends were noted when comparing mean values for utilities with no episode to
those with episodes on the one hand, and for problematic and nonproblematic utilities, on
the other. However, very few of these trends were confirmed by results of bivariate or
multivariate analyses (possibly due to the very discrete nature of microbial dissemination in
distribution systems). Apart from treatment-related variables, only the manure-related
variables exhibit some statistical impact. This may not be surprising, considering that many
of the responding utilities are located in zones under high agricultural pressure.
In terms of strict public health concern, it must be underlined that the so-called problematic
utilities are not necessarily serving water bearing more of a health threat than the water
served by the nonproblematic ones. In fact, most of reported episodes concern total
coliforms, which may tell more about the general salubriousness of the distribution system
than about real health hazards. Moreover, databases used for this study did not include data
35
on parasites like Giardia lamblia and Cryptosporidium parvum, nor on viruses or other
waterborne pathogens. These micro-organisms are of great concern, since they have been
tied to waterborne disease outbreaks in the United States and elsewhere. The only reason
these parameters were not included in this study is that there is an almost total lack of data
about them in small Quebec utilities.
The fact that data came from different sources has led to different data considerations,
which, to some extent, hindered this study. This situation may render difficult a comparison
of these results to those of other studies. Despite these limitations, this study has the
advantage of trying to create an overall portrait of microbiological and physicochemical
water quality in small Quebec utilities, and trying to establish and explain relationships
between the portrayed quality and some management practices or environmental factors
(manure). This may be interesting for those who want to know more about the specificity of
small utilities and the challenges they face, for instance, from a regulatory point of view.
Finally, it is worth mentioning that historical atypical bacteria data and water boiling
notices data were obtained from some of the studied herein small utilities. These data
strongly support the distinction made between nonproblematic and problematic utilities
(see Appendix B). However, the data were found about two years after the management
practices survey answers were obtained. At that time, this part of the research was already
completed. That is why atypical bacteria and water boiling notices data were not included
in this chapter.
1.6. References Antoun, E.N., Dyksen, J.E., and Hiltebrand, D.J. 1999. Unidirectional flushing – a powerful tool. J. Am.
Water Works Assoc. 91: 62-71. AWWA. 1994. An assessment of water distribution systems and associated research needs. American Water
Works Association, Denver, CO. AWWA. 1998. Water:\stats : the water utility database. American Water Works Association, Denver, CO. AWWA. 2000. Disinfection at small systems. AWWA Water Quality Division Disinfection Systems
Committee report. J. Am. Water Works Assoc. 92: 24–31. CMCH. 1992. Urban infrastructure in Canada. Canada Mortgage and Housing Corporation, Ottawa. Duranceau, S.J., Poole, J., and Foster, J.V. 1999. Wet-pipe fire sprinklers and water quality. J. Am. Water
Works Assoc. 91: 78-90.
36
Fougères, D., Gaudreau, M., Hamel, P.J., Poitras, C., Sénécal, G., Trépanier, M., Vachon, N., et Veillette R. 1998. Évaluation des besoins des municipalités québécoises en réfection et construction d’infrastructures d’eaux. INRS-Urbanisation, Montréal, 266 p.
Gouvernement du Québec. 1984. Règlement sur l’eau potable. Éditeur officiel du Québec, Québec. 7 p. Gouvernement du Québec. 1997. L’eau potable au Québec. Un second bilan de sa qualité : 1989–1994.
Ministère de l’Environnement et de la Faune, Québec. 36 p. Gouvernement du Québec. 2001. Règlement sur la qualité de l’eau potable. Ministère de l’Environnement,
Québec. 19 p. Haas, C.N. 1999. Benefits of employing a disinfection residual. Journal of Water Supply : Research and
Technology – Aqua 48: 11–15. LeChevallier, M.W., Schulz, W.H., and Lee, R.G. 1990. Bacterial nutrients in drinking water. In: Assessing
and controlling bacterial regrowth in distribution systems. AWWARF (ed.), pp. 143–201. American Water Works Association Research Foundation, Denver, CO.
LeChevallier, M.W., Welch, N.J., and Smith, D.B. 1996. Full-scale studies of factors related to coliform regrowth in drinking water. Appl. Environ. Microbiol. 62: 2201–2211.
LeChevallier, M.W. 1999. The case for maintaining a disinfectant residual. J. Am. Water Works Assoc. 91: 86–94.
Levallois, P. 1997. Qualité de l’eau potable et trihalométhanes. Bulletin d’Information en Santé Environnementale (BISE) 8: 1–4.
Kirmeyer, G.J., Foust, G.W., Pierson, G.L., Simmler, J.J., and LeChevallier, M.W. 1993. Optimizing chloramine treatment. AWWARF and AWWA, Denver, CO.
Kitaura, M., and Miyajima, M. 1996. Damage to water supply pipelines. Soils and Foundations 36: 325-333. Makar, J.M. 2000. A preliminary analysis of failures in grey cast iron water pipes. Institute for Research in
Construction, National Research Council Canada, 17 p. McDonald, S., Daigle, L., and Félio, G. 1997. Water distribution and sewage collection in Canada –
assessing the condition of municipal infrastructure, results from questionnaires to Canadian municipalities. Client Report A-7016.1, Institute for Research in Construction, National Research Council Canada.
Milot, J., Rodriguez, M.J., and Sérodes, J. 2000. Modeling the susceptibility of drinking water utilities to form high concentrations of trihalomethanes. Journal of Environmental Management 60: 155–171.
Payment, P. 1999. Poor efficacy of residual chlorine disinfectant in drinking water to inactivate waterborne pathogens in distribution systems. Canadian Journal of Microbiology 45: 709–715.
Rajani, B., and McDonald, S. 1995. Water main break data for different pipe materials for 1992 and 1993. Report No. A-7019.1, National Research Council, Ottawa, Canada.
Rajani, B.B., Makar, J.M., McDonald, S.E., Zhan, C., Kuraoka, S., Jen, C.-K., and Viens, M. 2000. Investigation of grey cast iron water mains to develop a methodology for estimating service life. AWWARF and AWWA, Denver, CO, 266 p.
Reiber, S. 1993. Chloramine effects on distribution system materials. AWWARF and AWWA, Denver, CO. Riopel, A. 1992. Les trihalométhanes dans les petits systèmes de distribution au Québec: campagnes
d’échantillonnage de 1987 et 1988. Direction des écosystèmes urbains, Ministère de l’Environnement, Gouvernement du Québec, 21 p.
Rodriguez, M.J., Sérodes, J.-B., and Morin, M. 2000. Estimation of water utility compliance with trihalomethane regulations using a modelling approach. Journal of Water Supply : Research and Technology – Aqua 49: 57–73.
Rodriguez, M.J., and Sérodes, J.-B. 2001. Spatial and temporal evolution of trihalomethanes in three water distribution systems. Water Res. 35: 1572–1586.
Rousseau, H. 1993. Suivi des concentrations de THM dans huit (8) réseaux de distribution d’eau potable au Québec. Division des eaux de consommation, Direction des écosystèmes urbains, Ministère de l’Environnement et de la Faune, Gouvernement du Québec, 54 p.
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Sobsey, M.D., Dufour, P.A., Gerba, C.P., LeChevallier, M.W., and Payment, P. 1993. Using a conceptual framework for assessing risks to health from microbes in drinking water. J. Am. Water Works Assoc. 85: 44–48.
Tremblay, H., et Trinh-Viet, H. 1995. Réseaux municipaux visés par le règlement sur l’eau potable susceptibles de présenter une concentration moyenne annuelle de THM supérieure à 100 µg/l : estimation des coûts de réalisation des ouvrages. Service de l’assainissement des eaux et du traitement des eaux de consommation, Ministère de l’Environnement et de la Faune, Gouvernement du Québec, 31 p.
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Villeneuve, J.P., and Hamel, P.J. 1998. Synthèse des rapports INRS-Urbanisation et INRS-Eau sur les besoins des municipalités québécoises en réfection et construction d’infrastructures d’eaux. INRS-Urbanisation, Montréal, 50 p.
CHAPTER 2 Spatial and temporal variation of drinking water
quality in ten small Quebec utilities Overview. The first part of this study has allowed identifying two types of small
municipal drinking water utilities in the province of Quebec: those that historically did not
have problems with distribution water quality, i.e., nonproblematic utilities, and those that
did have such problems, i.e., problematic utilities. That portrait focused on microbiological
water quality and management strategies, while also attempting to disclose relationships
between them and some important water quality and operational parameters. As such, the
portrait gives a general overview of the situation of small Quebec utilities.
Although that portrait was a very important and necessary first step to understanding the
situation of small Quebec utilities, it, nonetheless, had certain limits, since bearing
essentially on data that have been gathered a number of years before the study, that is
historical data. The question is whether or not the overall picture reflected through the
portrait corresponds to the current situation of the portrayed utilities as for water quality all
along the distribution systems, based on the opposition nonproblematic vs. problematic,
and what are the potential water quality parameters explaining the observed differences
between the two distinguished groups of utilities. This may allow identifying the
parameters upon which it would be possible to act to achieve better water quality in each of
the two utility groups, along with exploring the capacity of such utilities to simultaneously
and effectively handle the acute disease risk, associated with micro-organisms, and the
chronic health hazard tied to chlorination by-products. All of these raised questions made
indispensable initiating fieldwork in the corresponding municipalities to find answers. That
fieldwork, which represented the second part of this study, has been designed as a water
sampling campaign aiming at studying the spatial and temporal variation of drinking water
quality in a number of small Quebec municipal utilities.
39
Abstract. A comparative study relating to distributed water quality was undertaken in ten
small municipal drinking water utilities in Quebec. All of these utilities apply direct
chlorination to surface water or groundwater under the direct influence of surface water
without any previous treatment. These utilities were divided into two groups: four utilities
that had never or rarely served water infringing upon the provincial drinking water
microbiological standards (relating to fecal and/or total coliform bacteria), and six utilities
that very often infringed upon said standards. The objective of this study was to identify
key parameters responsible for the differences between the two groups of utilities, to
explore the capacity of studied utilities to simultaneously and effectively handle the acute
disease risk associated with micro-organisms and the chronic health hazard linked to
chlorination by-products, and to identify the parameters upon which it may be possible to
act in order to achieve better water quality in each of the two utility groups. The study
includes comparisons of characteristics of water quality at the source, chlorination
conditions in the plant, and water quality from the entrance to the extremity of the
distribution system. Results show that the differences between the two groups of utilities
are associated essentially with maintained chlorine residuals and heterotrophic plate count
bacteria populations in corresponding distribution systems and, to a lesser extent, to the
applied chlorine doses. Subsequent multivariate analyses allowed identification of variables
upon which utility managers may act in order to improve the quality of distributed water in
each group of utilities. For the group of utilities that had very little or no infringement,
these factors are related to disinfection levels, whereas for the group that often infringed
upon quality standards, raw water natural organic matter content reduction through source
water protection and raised chlorine doses and residuals appear to be the factors that may
lead to better microbiological quality of distributed water.
Key words: drinking water, water quality, distribution systems, small utilities, Quebec
Résumé. Une étude comparative sur la qualité de l’eau d’adduction a été menée dans dix
petits systèmes municipaux de distribution d’eau potable au Québec. Tous ces systèmes
appliquent une chloration directe à de l’eau de surface ou à de l’eau souterraine sous
influence directe de l’eau de surface, sans aucun autre traitement. Ces systèmes furent
40
répartis en deux groupes : quatre systèmes qui n’ont jamais ou ont rarement distribué de
l’eau dérogeant aux normes microbiologiques provinciales relatives à l’eau potable (en ce
qui a trait aux coliformes fécaux et/ou aux totaux) et six systèmes qui ont très souvent
dérogé auxdites normes. L’objectif de cette étude était d’identifier les paramètres clés
responsables des différences entre les deux groupes, d’explorer la capacité des systèmes à
l’étude à faire face simultanément et efficacement au risque de maladie aiguë associé aux
micro-organismes pathogènes d’une part, et au risque de maladie chronique relié aux sous-
produits de la chloration d’autre part, de même que d’identifier les paramètres sur lesquels
il serait possible d’agir afin d’obtenir une meilleure qualité de l’eau distribuée par chacun
des deux groupes de systèmes. L’étude comprend des comparaisons des caractéristiques de
la qualité de l’eau à la source, des comparaisons des conditions d’ajout du chlore aux postes
de chloration respectifs, et de la qualité de l’eau de l’entrée du système de distribution à
l’extrémité de celui-ci. Les résultats montrent que les différences entre les deux groupes de
systèmes de distribution d’eau potable sont principalement associées aux teneurs en chlore
résiduel libre et au nombre de colonies de bactéries hétérotrophes aérobies et anaérobies
facultatives (BHAA) dans les réseaux de distribution correspondants et, dans une moindre
mesure, aux doses de chlore appliquées. Des analyses multivariées subséquentes ont permis
l’identification de variables (ou facteurs) sur lesquels peuvent agir les gestionnaires des
systèmes municipaux en vue d’améliorer la qualité de l’eau distribuée par chaque groupe de
systèmes. Pour le groupe de systèmes qui n’avaient pas ou avaient peu de dérogations aux
normes provinciales de qualité, ces facteurs étaient associés aux niveaux de chloration,
tandis que pour le groupe qui dérogeait souvent aux normes susmentionnées, les facteurs
qui pourraient mener à une meilleure qualité microbiologique de l’eau distribuée seraient la
réduction de la teneur en matière organique naturelle de l’eau brute par une protection
adéquate de la source, de même que le rehaussement des doses et des résiduels de chlore.
Mots-clés : eau potable, qualité de l’eau, système de distribution, petits systèmes
municipaux, Québec
41
2.1. Introduction Small drinking water utilities have unique challenges: they have limited financial and
technical resources, often lack full-time staff to manage the utility, and may be
geographically isolated in rural areas where agricultural pollution is substantial. There are
about 1,000 small municipal utilities (i.e., serving 10,000 people or less) in Quebec, which
serve approximately 20% of the province’s population, or about one million people
(Gouvernement du Québec 1997). Most of these utilities apply simple chlorination (to
surface or groundwater) or no treatment at all (essentially groundwater). According to the
Quebec Ministry of Environment (QME), small utilities are known to have more difficulty
in ensuring distribution to their customers at all times of drinking water that complies with
established standards (Gouvernement du Québec 1997). Indeed, the majority of violations
of the 1984 Quebec drinking water regulations (QDWR) (Gouvernement du Québec, 1984)
concerned utilities serving fewer than 5,000 people.
Like some other Canadian provinces, Quebec updated its drinking water regulations shortly
after the E. coli outbreak in the small community of Walkerton (Ontario), in which 7 people
died and 2,300 became ill due to contaminated water. The new QDWR issued in June 2001
added new parameters (e.g., disinfection efficiency requirements for inactivation of Giardia
cysts, Cryptosporidium oocysts and viruses, as well as control over heterotrophic plate
count –HPC– bacteria and atypical bacteria, etc.) and strengthened control over others (e.g.,
turbidity, trihalomethanes –THMs–, etc.) (Gouvernement du Québec 2001). In doing so,
the 2001 QDWR make the challenges facing the province’s small utilities even greater,
especially considering the fact that very little is known about these utilities and the quality
of the water they serve. For instance, as a direct consequence of the 2001 QDWR,
practically all utilities which directly chlorinate surface water will have to either apply
filtration or opt for groundwater sources. In the U.S., small water utilities using either
surface or groundwater will, in the near future, have to comply with new National Primary
Drinking Water Regulations (USEPA 1989; USEPA 1998a; USEPA 1998b; USEPA 2000).
Additionally, as more and tighter regulations to enhance public health protection take
42
effect, the cost of providing safe drinking water in compliance with the updated regulations
will increase.
This article presents a study of spatial and temporal variation of distributed water quality in
ten (10) small utilities in Quebec. All of the utilities have chlorination as the only treatment
applied and use surface water or groundwater under the direct influence of surface water.
Four (4) utilities that historically did not have problems with microbiological water quality
(relating to total coliforms) and six (6) that did have such problems are compared through
microbiological and physicochemical water quality. The objectives of this study were: 1) to
identify key parameters responsible for the differences between the two groups of utilities;
2) to explore the capacity of studied utilities to simultaneously and effectively handle the
acute disease risk associated with micro-organisms and the chronic health hazard tied to the
presence of chlorinated disinfection by-products – DBPs – in drinking water; and 3) to
identify the variables (i.e., parameters) upon which it may be possible to act upon in order
to achieve better water quality in each of the two utility groups. Such information may be
important for managers of small utilities and for government officials in terms of policy
making.
2.2. Methodology Under the provisions of the 1984 QDWR, all utilities serving 51 or more people had to send
results of their microbiological and physicochemical distribution water testing to the QME
at a frequency related to their size. It is important to note that the same requirement is valid
in the 2001 QDWR for utilities serving 21 or more people. In a database of small municipal
utilities obtained from the QME in 1999, and containing data gathered by virtue of the 1984
QDWR follow-up, it was possible to distinguish between two types of utilities. The first
type included utilities that had never recorded coliform positive samples or had recorded
such samples only on rare occasions. The second type encompassed utilities that often
recorded coliform positive samples. For the purpose of this research, data from three years
(i.e., 1997 through 1999) were utilized. Based on data received from the QME, two
concepts were defined: coliform episode and problematic utility. A coliform episode
43
indicated one or a set of coliform positive samples occurring in a given distribution system
during the three-year period (1997-1999), separated by at least 15 days from any other
coliform positive sample in the same system. A problematic utility was defined as a utility
that recorded one or more coliform episodes in at least two of the three reference years.
Consequently, utilities that recorded no coliform episode, or had episodes in only one of the
above-mentioned three years, were called nonproblematic utilities.
It is important to note that this research had been originally designed with the main goal of
finding some responses and/or giving some explanations with respect to a statement of fact
made by the QME in its document entitled “L’eau potable au Québec. Un second bilan de
sa qualité : 1989–1994” (Gouvernement du Québec 1997) where the term “réseaux
problématiques” was used to designate small or large distribution systems that frequently
recorded coliform occurrences between 1989 and 1994). That statement of fact can be
formulated as follows: utilities that have comparable technical, human and financial
resources may be very different as for their historical microbiological water quality, and
this is particularly frequent among small utilities. Moreover, in the QME small utility
database originally used to determine the concept of “problematic utility”, and that
contained results of about 65,000 water sample analyses for the period from January 1997
to December 1999, it was found that about 25 percent of the 927 small utilities (that is
about 230 utilities) experienced repetitive coliform episodes. It was that fact that led to the
division of small utilities into “nonproblematic” and “problematic” based on their historical
microbiological water quality. The ten small utilities described in this paper have been
chosen among the 927 mentioned earlier, with the “microbiological status” they had (i.e.,
having already been classified as problematic or not) in the initial QME database according
to the number of coliform episodes they experienced from 1997 to 1999. It is reasonable to
think that even though the historical data received from the QME may be resulting from
periodic and sparse monitoring of bacteriological samples in distribution systems, drawing
valid conclusions is possible when a high number of utilities (927 utilities, with 65,000
water samples analyzed) is involved and multiyear historical data are available for each
utility.
44
2.2.1. Small utilities under study In 1999, a mail survey was conducted by the authors to enquire about small utilities
management practices (Rodriguez et al. 2002). The questionnaire was sent to about 250
Quebec utilities serving from 201 to 10,000 people. 114 utilities responded, resulting in a
response rate of about 46%. From these 114 utilities, 10 were selected for further study.
The 10 utilities were selected based on the following criteria: 1) they used either surface
water (lake or stream) or groundwater under direct influence of runoff (from surface wells);
2) chlorination was the only treatment applied ; 3) for logistic reasons, they had to be
located relatively close (within a radius of about 150 km; see Figure 2.1) to the Quebec
City area, where the analytical laboratory is located (Laval University); 4) the 10 utilities
encompassed a group of problematic utilities and a group of nonproblematic utilities; and
5) utility managers had to be in agreement with the proposed study and offer to co-operate
by favoring easy access to sampling points and historical data on water quality. Under these
criteria, four nonproblematic and six problematic utilities were selected.
2.2.2. Sampling program strategy In order to generate information about microbiological and physicochemical water quality
of the 10 utilities under study on a spatial and temporal basis, five sampling campaigns
were undertaken between May and October 2001. In the Quebec City area, this period
encompasses spring, summer and fall conditions, the period during which surface water
quality varies considerably with water temperatures generally higher than 5 °C (for the rest
of the year, the ice cover protects surface waters naturally from runoff-related
contaminants). The period from May to October corresponds relatively well to the critical
period for microbial growth within distribution systems, with subsequent biofilm
development, odour and taste problems and other problems.
Each utility was sampled five times, or once a month (May, June, July, August and
October), at four different sampling points: raw water, chlorinated water (i.e., water from
the chlorination facility outlet), water from the central part of the distribution system, and
45
Figure 2.1. Localization of the ten small utilities
Bas-Saint-Laurent administrative region Chaudière-Appalaches administrative region
Quebec-City administrative region Centre-of-Quebec
administrative region
01
03
12
17
46
water from the system’s extremity. In each campaign, 10 water quality parameters were
measured: three microbiological (total coliform, HPC and atypical bacteria) and seven
physicochemical (temperature, pH, turbidity, total organic carbon –TOC–, ultraviolet
absorbance at the 254 nanometer wavelength –UV254 nm–, free chlorine residuals and
THMs). Three parameters (temperature, pH and free chlorine residuals) were measured on-
site, whereas the seven others were measured in the laboratory at Laval University. An
important operational parameter, the chlorine dose, was also taken into consideration. The
chlorine dose value was obtained either directly from the operator’s report book or
calculated from utility meter readings and the quantity of chlorine utilized.
2.2.3. Analytical procedures
2.2.3.1. Microbiological analyses Samples for bacteriological testing were collected in Nalgene® polypropylene 500-mL
screw capped bottles. Before sampling, 2 mL of sodium thiosulfate 5% w/v were added to
the bottles, which were then sterilized in an autoclave for 15 minutes at 135 °C. All
samples were collected after flushing the spigots for 3 to 5 minutes according to Standard
Methods (APHA-AWWA-WEF 1998). Sterile bottles were only opened at the very
moment of their filling, and were carefully handled to avoid potential extraneous
contamination. Samples were then placed on ice for transport to the laboratory. Prior to any
handling, the working surface was disinfected with a disinfectant soap (±4% v/v).
Moreover, all handling was done near a flame to prevent extraneous contamination and
maintain a sterile working zone.
The three microbiological parameters used for the purpose of this study were total coliform
bacteria, HPC bacteria and atypical bacteria. As in the U.S. (USEPA 1993), the presence of
coliform bacteria is used by Quebec drinking water professionals as an indicator of possible
microbiological contamination. Based on World Health Organization (WHO) reports,
coliform bacteria are the micro-organisms most commonly used to assess drinking water
quality around the world (OMS 1994).
47
HPC bacteria are found both in bulk water and biofilm. HPC bacteria may be good
indicators of the overall microbiological quality of distributed water. According to QME,
these bacteria may be even better indicators than total coliforms (Gouvernement du Québec
1997). LeChevallier et al. (1990) mentioned that HPC bacteria could interfere with the
coliform analysis. Others emphasize that abnormally high HPC counts could cause taste
and odour problems in tap water (Pipes 1982; Reasoner 1990). Levels of HPC bacteria may
also be used to assess microbial growth on distribution pipe surfaces and to measure
bacterial after-growth in water mains (LeChevallier et al.1990; Carter et al. 2000).
Atypical bacteria may also be considered as distribution water quality indicators
(Gouvernement du Québec 1997). This group of bacteria is somewhat difficult to define,
because it encompasses a number of genera and species. These bacteria are able to grow on
m-Endo LES medium but their colonies may or may not show the green sheen typical of
true coliform bacteria; i.e., they are atypical. Atypical bacteria counts higher than 200
cfu/100 mL may hinder coliform detection in water samples, since the latter may not be
able to grow under such conditions (Gouvernement du Québec 1997). So, from the strict
point of view of a potential threat to public health, it appears that high HPC bacteria counts
are less harmful than high atypical bacteria counts. The reason is that high HPC bacteria
counts may only cause organoleptic degradations of distributed water quality, while high
atypical bacteria counts may indicate the presence of harmful organisms in distributed
water.
Total coliforms were enumerated by the membrane filter procedure with 0.45-µm-pore-size
membrane filters and m-ENDO LES (APHA-AWWA-WEF 1998). This culture medium is
the standard medium for total coliform testing in the U.S.; coliform colonies have a typical
metallic green sheen. The coliform plates were incubated for 48 ± 2 hours at 35 ± 2 °C
rather than 24 ± 2 hours at 35 ± 0.5 °C because the authors used method 9225-C of
Standard Methods for the Examination of water and wastewater (APHA-AWWA-WEF
1998) rather than method 9225-B. Culture purification has not been done and no
confirmation test has been performed. As a consequence, the total coliform results must be
considered as presumptive total coliform counts. HPC bacteria were enumerated by the
48
spread plate procedure with R2A agar incubated at 35 ± 2 °C for 48 ± 2 hours. Atypical
bacteria were enumerated on the same filter media as total coliforms. Even though m-
ENDO LES is considered a selective medium, some other bacterial species can grow on it.
Hence, all colonies not showing the metallic green sheen were classified as atypical.
Controls were prepared from sterile demineralized water for all bacteriological analyses.
The procedures for preparing the controls were the same as those used for the samples. This
ensured that no extraneous contamination took place and skewed the results. Moreover, all
microbiological determinations were performed in triplicate to ensure that the results were
reproducible and, once again, to ensure that observed data were not distorted because of
potential extraneous microbial contamination. Incubation temperatures and duration for
coliform and atypical bacteria were identical to those mentioned for HPC. The enumeration
was performed by counting the colonies on filter media. Since triplicate analyses were
available, a mean colony number was calculated from the three obtained results. This
number was then converted into cfu/100 mL, for coliform and atypical bacteria, or into
cfu/mL for HPC bacteria. Please note that all microbiological sampling campaign data are
shown in Appendix C.
2.2.3.2. Physicochemical analyses Physicochemical parameters analyzed during the sampling campaign were temperature, pH,
turbidity, TOC, UV254 nm, free chlorine, and THMs. Temperature, pH, and free residual
chlorine were measured at the sampling sites. For turbidity, TOC and UV254 nm, Nalgene®
polypropylene or high-density polyethylene bottles were used to collect water samples. The
water temperature was measured using a standard glass alcohol column thermometer
(Fisher–14–997) or, when pH and temperature were measured at the same sampling point,
with the use of a thermocouple probe. Water pH was measured using an Accumet® model
25 pH/ion-meter and a Hanna HI–1332–B probe. Turbidity was measured using a Hach
2100–N turbidimeter. Thirty milliliter (30 mL) sample volumes were used to measure this
parameter once the instrument was calibrated against a secondary standard consisting of a
metal oxide suspension in a gel. Free residual chlorine was determined by the DPD
49
(diethyl-para-phenylenediamine) colorimetric method using a Hach DR/890 colorimeter
and Hach DPD free chlorine reagents (using 10 mL water samples) (APHA-AWWA-WEF
1998). The procedure used for water organic carbon measurement actually determined not
TOC but non-purgeable organic carbon (NPOC). NPOC was measured by authors instead
of TOC only because of laboratory restrictions (the analyzer available at the laboratory was
not designed for samples high in inorganic carbon, therefore it becomes necessary to purge
the acidified samples). Moreover, the authors assumed that the fraction of volatile organic
carbon (VOC) was negligible in waters analyzed in this study, as is generally the case for
natural raw waters. This is why NPOC content was considered approximately the same as
TOC content and interpreted as such. TOC was determined by means of a Shimadzu TOC-
5000 total organic carbon analyzer. The method consisted of 200 µL HCl-acidified water
samples aerated with pure ultra zero air (Praxair Specialty Gases and Equipments) in order
to remove inorganic carbon. Finally, UV254 nm was determined using a Jenway 6405—
UV/Vis (ultraviolet and visible) spectrophotometer at 254-nanometer wavelength (using a 1
cm Suprasil® quartz cell).
Samples for THM determinations were collected in 300 mL glass BOD (biochemical
oxygen demand) bottles, which are airtight thus avoiding THM volatilization. Before
collecting samples, a standardized dose (approximately 500 mg/L) of a dechlorinating
agent (sodium thiosulfate or ammonium chloride) was added to each bottle, which was then
placed in a Thelco® Model 18 PS (Precision Scientific) incubator for 12 hours at 110 oC to
evaporate the water. THMs were then measured using a Perkin Elmer (Autosystem XL) gas
chromatograph (GC) equipped with an electron-capture detector and a ZB–624 column (30
m X 0.32 mm ID X 1.8 µm FT). Analytical criteria for this determination were injector,
oven and detector temperatures (175 oC, 80 oC and 375 oC, respectively), carrier gas
(helium: 8.5 mL/min during 7 minutes, followed by a flow ramp of 3.5 mL/min until 15
minutes, then by a flow of ramp of 15 mL/min during 11 minutes), make-up gas
argon/methane P5 Mix at 30 mL/min (Praxair Specialty Gases and Equipments) , analysis
duration (17 minutes) and injection volume (1 µL of the sample). The THMs in the water
sample are concentrated by liquid-liquid extraction with pentane. GC analysis was
50
conducted based on USEPA method 551.1 described by Rodriguez and Sérodes (2001).
Please note that all microbiological sampling campaign data are shown in Appendix C.
2.3. Results and discussion Table 2.1 presents general characteristics of the 10 studied utilities. As shown, only two
utilities obtain their raw water from lakes; the others obtain it from surface wells (in the
form of springs with a single basin or with horizontal drainpipes). All of them use
chlorination as the only treatment, using a 12% sodium hypochlorite solution. Only two
utilities are located in municipalities under very high agricultural pressure.
Table 2.1. General characteristics of the ten small utilities
Utilities Population served
Water source Agricultural status of municipality under
study*
Coliform episodes in 1997-1999
Utility microbiological status
I. 1200 Lake No 2 Problematic
II. 1933 Lake No 1 Nonproblematic
III. 1166 Surface well No 0 Nonproblematic
IV. 500 Surface well No 6 Problematic
V. 2000 Surface well No 0 Nonproblematic
VI. 1075 Surface well No 8 Problematic
VII. 730 Surface well No 0 Nonproblematic
VIII. 4210 Surface well No 2 Problematic
IX. 1600 Surface well Yes 6 Problematic
X. 400 Surface well Yes 5 Problematic
* This factor is measured by the annual balance of phosphorus in terms of kilograms of phosphorous (P2O5) per hectare. It considers the total manure production within the municipality, the nutrient requirements of crops and the cultivated area. When the annual balance is more than 20 kg P2O5/ha/year or when the municipality is located in watersheds with already significant phosphorus excess in the soils, the Quebec provincial government considers the municipality as being in manure surplus. Even if such an annual balance is not calculated based on watershed limits but rather on municipal limits, it can be used as an indicator of the susceptibility of surface waters to be contaminated by surface or subsurface runoff.
51
2.3.1. Characteristics of raw water Raw water characteristics of nonproblematic utilities were compared to those of
problematic utilities in order to depict potential differences between them at the source
water stage. To carry out this comparison, a number of key raw water parameters were
chosen: turbidity, TOC, UV254 nm, total coliform, HPC and atypical bacteria. Abnormally
high counts of coliforms in source water would indicate poor quality requiring steady
disinfectant (i.e., chlorine) residuals to prevent breakthrough or regrowth of these
organisms in the distribution system. The absence of a treatment (e.g., coagulation,
flocculation, settling, filtration) to remove colour (due to natural organic matter – NOM –)
and suspended matter means that TOC, UV254 nm (used as indicators of organic matter in
drinking water) (Krasner 1999), and turbidity will enter the distribution system in levels
comparable to those encountered in the source water. This situation may reduce
disinfection efficiency (McCoy and Olson 1986), increase chlorine demand and favour
bacterial breakthrough, regrowth or recovery (LeChevallier et al. 1996). It is important to
mention that assimilable organic carbon – AOC – and biodegradable organic carbon –
BDOC – are better indicators of the availability of microbial nutrients in drinking water
(van der Kooij et al. 1999), but these indicators were not defined in this study.
Water temperature, an important parameter for microbial growth, remained relatively low
and showed little variation. This is understandable, since most of the utilities obtain their
water from surface wells, with the water remaining relatively cool, even during summer
months, because of natural protection from the rays of the sun. Overall, the average raw
water temperature recorded was 8.9 oC (with the 10th percentile = 6.5 oC and the 90th = 15.3 oC).
In general terms, the raw water appeared to be of good quality in both groups of utilities.
Indeed, only two of them draw their raw water from strictly surface water sources, —i.e.,
lakes—; the others supplied from surface wells. Consequently, during the study period, the
average raw water turbidity, UV254 nm and TOC levels were low. Average values for
those parameters were 0.5 ntu, 0.046 cm-1 and 1.7 mg/L, respectively (for the two lakes, the
average values were 1.16 ntu, 0.115 cm-1 and 3.68 mg/L, respectively). Moreover, previous
52
studies showed that these values could be much higher in surface raw waters in southern
Quebec (Milot et al. 2000; Vinette 2001). Raw water total coliform counts also appeared
very low in comparison with other southern raw waters in Quebec (Payment et al. 2000).
Figure 2.2-a to Figure 2.2-f feature some differences with regard to source water
physicochemical quality between the two groups of utilities. These figures illustrate group
differences as well as monthly differences. In both groups, the highest mean values for
these three parameters (corresponding to lesser water quality) were observed in June and, in
nonproblematic utilities, to a lesser degree in October. For turbidity, measured value
variations appeared higher in nonproblematic utilities, but mean values are relatively
comparable for all months between the two groups of utilities, with the exception of June.
For UV254 nm, mean values were generally higher in nonproblematic utilities, but
maximum values were much higher in problematic utilities. UV254 nm appeared subject to
important value fluctuations in the problematic utilities: minima were very low, maxima
relatively high. As for TOC, June and October exhibited relatively important differences in
terms of mean values when the two groups of utilities were compared.
Differences with respect to raw water microbiological quality are shown in Figure 2.3-a
toFigure 2.3-f. At first glance, monthly differences appear much greater between the two
groups for microbiological raw water quality than they are for physicochemical quality.
Hence, for total coliforms, June and October showed the highest counts in nonproblematic
utilities, whereas July was the month with the highest count in problematic utilities. For all
other months, even maximum values rarely reached 30 cfu/100 mL. It is important to note
however, that for all months other than June and October, problematic utilities recorded
higher counts in terms both of mean values and maxima. This may be an indication that
problematic utilities are at more frequent risk of coliform contamination. Another important
indication is that the highest counts for total coliforms correspond to the highest measured
values of turbidity, UV254 nm, and TOC in both nonproblematic (June and October) and
problematic utilities (June, July, August); however, this appears particularly clear in
nonproblematic utilities. As far as HPC bacteria are concerned, May and June are the two
53
0
0.6
1.2
1.8
2.4
May June July Aug. Oct.
Sampling campaign months
Turb
idity
, ntu
0
0.04
0.08
0.12
0.16
May June July Aug. Oct.
Sampling campaign months
uv25
4 nm
, cm
-1
0
0.04
0.08
0.12
0.16
May June July Aug. Oct.
Sampling campaign months
uv25
4 nm
, cm
-1
0
2
4
6
8
May June July Aug. Oct.
Sampling campaign months
TOC
, mg/
L
0
2
4
6
8
May June July Aug. Oct.
Sampling campaign months
TOC
, mg/
L
0
0.6
1.2
1.8
2.4
May June July Aug. Oct.
Sampling campaign months
Turb
idity
, ntu
a. b.
(NP) (P) c. d. (NP) (P) e. f.
(NP) (P)
Figure 2.2. Comparison of raw water quality between nonproblematic (NP) and problematic (P) utilities: a and b, turbidity; c and d, TOC; e and f, UV254 nm . Bar, mean value; upper bar, maximum; lower bar, minimum
54
0
30
60
90
120
May June July Aug. Oct.
Sampling campaign months
Tota
l col
iform
s, c
fu/1
00m
L
0
30
60
90
120
May June July Aug. Oct.
Sampling campaign months
Tota
l col
iform
s, c
fu/1
00m
L
0
1500
3000
4500
May June July Aug. Oct.
Sampling campaign months
HPC
bac
teria
, cfu
/mL
0
1500
3000
4500
May June July Aug. Oct.
Sampling campaign months
HPC
bac
teria
, cfu
/mL
0
100
200
300
400
May June July Aug. Oct.
Sampling campaign months
Aty
pica
l bac
teria
, cfu
/100
mL
0
100
200
300
400
May June July Aug. Oct.
Sampling campaign months
Aty
pica
l bac
teria
, cfu
/100
mL
a. b.
(NP) (P) c. d.
(NP) (P) e. f.
(NP) (P)
Figure 2.3. Comparison of raw water quality between nonproblematic (NP) and problematic (P) utilities: a and b, total coliforms; c and d, HPC bacteria; e and f, atypical bacteria. Bar, mean value; upper bar, maximum; lower bar, minimum. Atypical bacteria quantification limit was 400 cfu/100 mL.
55
months that showed significant differences between the two groups. This parameter appears
less influenced than the three above-mentioned physicochemical ones, but the fact that it
exhibits its highest values in July and August may indicate a greater dependence on
temperature. Atypical bacteria counts show their highest mean values in June and October
in nonproblematic utilities. It is interesting to note that the same trend is observed for total
coliform counts in these utilities. In problematic utilities, May, July, and August recorded
the highest mean values of atypical bacteria counts. These counts show a monthly trend that
is different from the one exhibited by coliform counts in problematic utilities; rather, it
indicates a much greater similarity with HPC bacteria counts in the same group (as shown
by comparing monthly trends for May, July, and August). This fact is surprising, since the
same type of bacteria seemed to behave differently depending on the group of utilities. In
fact, for problematic utilities, atypical bacteria appear to behave in a way similar to HPC
bacteria, having their numbers boosted by warm water temperatures (that favour bacterial
growth and multiplication), especially in July and August. In nonproblematic utilities, the
similarity in monthly trends with total coliform counts, as well as turbidity, UV254 nm, and
TOC, may suggest a possible impact of these three physicochemical parameters on total
coliform and atypical bacteria counts. It is important to note that in Figure 2.3-e and Figure
2.3-f maximum atypical bacteria counts are assumed equal to 400 cfu/100 mL because the
colony counting method utilized did not allow counting of plates over 400 cfu/100 mL.
Such value has been considered as maximum although some monthly atypical bacteria
counts may in reality be higher.
As a conclusion to these monthly water quality profiles, it must be noted that the
differences in raw water quality between the two groups of utilities were not great. In order
to determine if the observed differences are statistically significant, a test of means
(independent samples t test) was performed. It indicates, as shown in Table 2.2, that the
observed mean differences between nonproblematic and problematic utilities were not
significant (the difference being statistically significant when P<0.10). The results of this
statistical analysis suggest that other factors (related for instance to disinfection practices,
distribution system management or properties, etc.) could have a greater impact than the
raw water on the microbiological water quality in the distribution system.
56
Table 2.2. Comparison of mean differences between nonproblematic and problematic utilities for raw water during the period under study
Parameters Utilities Number of samples
Mean P*
nonproblematic 20 .57 Turbidity, ntu problematic 30 .45
.403
nonproblematic 20 .055 UV254 nm, cm-1 problematic 30 .038 .152
nonproblematic 20 1.90 TOC, mg/L problematic 30 1.42 .223
nonproblematic 20 18 Total coliforms, cfu/100 mL problematic 30 15 .684
nonproblematic 20 704 HPC bacteria, cfu/mL problematic 30 885 .601
nonproblematic 20 172 Atypical bacteria, cfu/100 mL problematic 30 117 .236
* Means test significance level (Student’s t-test)
2.3.2. Characteristics of treated and distributed water A comparative study of the water quality at the chlorination facility outlet and in the
distribution system was also carried out. Emphasis was placed on the applied chlorine dose,
the HPC and atypical bacteria, as well as on residual chlorine and chlorination by-products
(THMs).
2.3.2.1. Chlorination levels
All the utilities in this study use chlorination as the unique treatment. The chlorination dose
is an important operational parameter that affects micro-organism inactivation, available
residual chlorine and DBP occurrence in distributed water (Connell 1996; Rodriguez et al.
57
0
2
4
6
8
May June July Aug. Oct.
Sampling campaign months
Chl
orin
e do
se, m
g/L
0
2
4
6
8
May June July Aug. Oct.
Sampling campaign months
Chl
orin
e do
se, m
g/L
1999). Figure 2.4-a and Figure 2.4-b feature this parameter. The mean values were
relatively close, although generally slightly higher in nonproblematic utilities (Figure 2.4-
a). However, monthly standard deviations (as much as 2.90 mg/L in July) and maxima in
the latter are almost twice as high as those of corresponding sampling months for
problematic utilities. Nonetheless, the subsequent means test performed for the dose
confirms that the statistical difference between the mean values is not significant (P =
0.352, mean value for nonproblematic utilities = 2.63 mg/L and the mean value for
problematic utilities = 2.19 mg/L). Because of a lack of adequate data (for example, no
information was available about the hydraulic efficiency factor), the disinfection
effectiveness (i.e., the CT values) could not be estimated. Thus, the emphasis was placed on
the impact of the dose on microbiological water quality, as well as on the free residual
chlorine concentration and THMs.
a. b.
(NP) (NP)
Figure 2.4. Comparison of applied chlorine doses between a nonproblematic (NP) utilities and b problematic (P) utilities. Bar, mean value; upper bar, maximum; lower bar, minimum
58
2.3.2.2. Microbiological water quality During the five-month sampling campaign, seven total coliform positive samples for total
coliforms were recorded. Three were found in samples from nonproblematic utilities (one
at a chlorination facility outlet, two in the central part of distribution system) and four in
samples from problematic utilities (two at a chlorination facility outlet, two in the central
part of distribution system). It was surprising that three of the total coliform positive
samples came from a chlorination facility outlet. This may have been the result of either
poor chlorination effectiveness (bad mixing or insufficient contact time of chlorine with
water) or extraneous contamination (for example, coming from operators). Likewise, it was
surprising that none of the positive coliform samples came from a distribution system
extremity which is known to be a location where free residual chlorine and water flowrate
are generally low. However, the detected coliform cases could not be classified as
violations of the QDWR in force, since none of them recorded more than 10 cfu/100 mL.
As for HPC bacteria, three violations (i.e., > 500 cfu/mL) of the QDWR were recorded in
distribution systems. All of them were from problematic utilities: one from the central part
of the distribution system and two from the extremity of systems. It is interesting to note
that problematic utilities appeared to exhibit a greater predisposition to HPC bacterial
growth, particularly when considering the potential links that may exist between HPC and
coliform bacteria (LeChevallier 1990). The fact that practically all violations linked to HPC
bacteria came from a distribution system extremity also supports the widespread opinion
that control samples for these organisms must be taken precisely at that location
(Gouvernement du Québec 2001). Only one violation (i.e., > 200 cfu/100 mL) on the
QDWR was recorded for atypical bacteria counts in a distribution system. It came from the
chlorination facility outlet at a problematic utility. The fact that atypical bacteria were
detected in abnormal numbers at the same location where coliforms were detected three
times is interesting, considering the relationship that may exist between atypical and
coliform bacteria (Gouvernement du Québec 1997). However, the chlorination
effectiveness may also be a factor.
59
Average HPC counts in nonproblematic utilities were compared to those in problematic
utilities (Figure 2.5-a, Figure 2.5-b). It appears that regrowth takes place in both cases, but
the phenomenon is of greater magnitude in problematic utilities. Moreover, the means
difference between the two groups of utilities is statistically significant (P<0.10) for the
chlorination facility outlet (Table 2.3). This indicates a possible deficiency in the
disinfection procedures of problematic utilities (which exhibited a much higher mean count
value). However, this difference is also important for the other sampling points, although
not statistically significant. Since levels for indicators of organic matter were found to be
relatively comparable between the two groups, the observed result seems to be related to: 1)
insufficient mixing of recently- added chlorine with bulk water, or 2) very low residual
chlorine in problematic utilities.
The results obtained for atypical bacteria showed no significant difference between the two
groups of utilities in terms of growth (Figure 2.5-c, Figure 2.5-d). Likewise, statistical
results of means tests proved not to be significant between the groups, despite obvious
monthly fluctuations in average counts. It appears that HPC bacteria grew more actively in
both utility groups than the atypical bacteria did, and monthly growth patterns were very
different from those observed from compared raw water values.
2.3.2.3. Residual chlorine Maintaining an adequate level of residual chlorine is of great importance in terms of
distribution water quality management (Sérodes et al. 1998; Haas 1999). Figure 2.6-a and
Figure 2.6-b indicate a considerable difference between free chlorine levels of
nonproblematic and problematic utilities. Average concentrations of measured residual
chlorine of nonproblematic utilities were higher than 0.2 mg/L during the period under
study at the three sampling points: the chlorination facility outlet water, water from the
central part of the distribution system, and water from the system’s extremity. Conversely,
in problematic utilities, levels of free residual chlorine in both the central part and the
distribution system extremity were on average lower than 0.1 mg/L. This level of residual
chlorine may appear as a minimum in order to prevent microbiological deterioration of
60
0
100
200
300
400
facility center extremity
Localization
HPC
bac
teria
, cfu
/mL
0
5
10
15
20
facility center extremity
Localization
Aty
pica
l bac
teria
, cfu
/100
mL
0
5
10
15
20
facility center extremity
Localization
Aty
pica
l bac
teria
, cfu
/100
mL
0
100
200
300
400
facility center extremity
Localization
HPC
bac
teria
, cfu
/mL
a. b.
(NP) (P)
c. d.
(NP) (P)
Figure 2.5. Comparison of HPC bacteria and Atypical bacteria between a and c nonproblematic (NP) utilities; and b and d problematic (P) utilities. Bars represent monthly means (from left: May, June, July, August, October)
61
Table 2.3. Comparison of mean differences between nonproblematic and problematic utilities for distributed water quality at (a) chlorination facility outlet, (b) central part of distribution system, and (c) system extremity Parameters Utilities Number of
samples Mean P*
nonproblematic 20 13 HPC bacteria (a) problematic 30 28 .055
nonproblematic 20 50 HPC bacteria (b) problematic 30 96 .194
nonproblematic 20 52 HPC bacteria (c) problematic 30 115 .217
nonproblematic 20 3 Atypical bacteria** (a) problematic 30 22 .181
nonproblematic 20 2 Atypical bacteria** (b) Problematic 30 12 .139
nonproblematic 20 2 Atypical bacteria** (c) Problematic 30 13 .177
nonproblematic 20 0.69 Free chlorine (a) problematic 30 0.39 .081
nonproblematic 20 0.33 Free chlorine (b) problematic 30 0.14 .074
nonproblematic 20 0.30 Free chlorine (c) problematic 30 0.12 .085
nonproblematic 20 14.4 Total THMs (a) problematic 30 8.49 .153
nonproblematic 20 21.5 Total THMs (b) problematic 30 12.0 .100
nonproblematic 20 22.3 Total THMs (c) problematic 30 12.2 .083
* Means test significance level (Student’s t-test) ** Calculated with assumed maximum value of 400 cfu/100 mL
62
0
0.25
0.5
0.75
1
facility center extremity
Localization
Free
chl
orin
e, m
g/L
0
0.25
0.5
0.75
1
facility center extremity
Localization
Free
chl
orin
e, m
g/L
0
10
20
30
40
facility center extremity
Localization
Tota
l TH
Ms,
ug/
L
0
10
20
30
40
facility center extremity
LocalizationTo
tal T
HM
s, u
g/L
a. b.
(NP) (P) c. d.
(NP) (P)
Figure 2.6. Comparison of free chlorine and total THMs between a and c nonproblematic (NP) utilities; and b and d problematic (P) utilities. Bars represent monthly means (from left: May, June, July, August, October)
63
water quality within the distribution system since, according to Haas (1999), water
distribution systems in the United States usually carry residuals more than 0.1 mg/L. The
difference in average residual chlorine between the two types of utilities was found to be
statistically significant (P<0.10) for each of the three sampling locations (Table 2.3). Such
results give a good indication of the benefits of sufficient levels of residual chlorine.
Considering that indicators of chlorine demand related to raw water (TOC, UV254 nm,
turbidity) were relatively close between the two groups of utilities, observed differences of
residual chlorine levels are most probably associated with chlorination practices at the
facility (applied chlorine doses, contact time, etc.) or to the presence of oxidizable material
attached to the pipe surfaces in the distribution system. However, it is important to mention
that there are many other factors that likely affect chlorine decay, including the type of
TOC, ammonia, iron, etc.
2.3.2.4. Chlorination by-products When added to water, chlorine reacts with NOM, resulting in the formation of DBPs
(Bellar et al. 1974; Rook 1974), which have a carcinogenic potential. Four THMs are the
most commonly known group of DBPs: chloroform, bromoform, chlorodibromomethane
and bromodichloromethane (Levallois 1997). The sum of the values of these four species is
called total THMs. Because one of the authors’ goals is to explore the capacity of the
studied utilities to simultaneously handle the acute disease risk associated with
microorganisms and the chronic health hazard linked to the presence of DBPs in drinking
water (Fowle and Kopfler 1986; Putnam and Graham 1993), total THMs were analyzed
concurrently with microorganisms. THM levels observed during the sampling campaign are
low (the average for nonproblematic utilities was: at the facility outlet, 14.4 µg/L, at the
system extremity, 22.3 µg/L; for problematic utilities: at the facility outlet, 8.49 µg/L, at the
extremity, 12.2 µg/L). This is because 8 out of 10 utilities extract their raw water from
surface wells, such water sources containing relatively little NOM, the principal THM
precursor. By comparison, the two utilities that draw their raw water from lakes had an
average THM level of 33.0 µg/L at the facility outlet, and 49.6 µg/L at distribution system
extremity. Mean differences for total THM appear significant at first glance (Figure 2.6-c
64
and Figure 2.6-d). In fact, statistical tests show that mean total THM differences between
the two groups are almost significant for water sampled at the chlorination facility outlet,
and significant (P<0.10) for water from the central part of the distribution system and for
water at the system extremity (Table 2.3). In all three cases, average THM levels in
nonproblematic utilities were almost twice the levels found in problematic ones. This result
means that utilities that are nonproblematic from a microbial point of view may experience
some difficulties with DBP occurrence (measured values being, however, notably below
the maximum contaminant levels of the QDWR in force). This result is very probably
related to the higher chlorine doses applied in nonproblematic utilities in comparison to
problematic ones. Such doses ensure higher levels of residual chlorine in the distribution
system in nonproblematic utilities, but also generate higher levels of THMs. In addition,
one may also suspect the reactivity of the NOM to be a supplementary factor explaining
such important differences (mean values of measured UV254 nm being slightly higher in
nonproblematic utilities). These results underscore the difficulty small utilities experience
by not having treatment before chlorination to efficiently handle microbial and chronic
health risks simultaneously.
2.4. Multivariate analyses Previous analyses showed that factors explaining differences between nonproblematic and
problematic utilities are the applied chlorine dose, free residual chlorine and HPC bacteria
counts in distribution systems, with the last two factors showing significant differences. To
better understand factors that significantly influence the distributed water quality,
multivariate analyses were performed. The purpose of these analyses is to explain the water
quality within each group of utilities after chlorination, i.e., from the chlorination facility
outlet to the distribution system extremity.
Because of the nature of the variables to explain (called dependent variables), a linear
multivariate regression analysis was performed. This analysis provides an estimate of the
linear relationship between a dependent variable and one or more explanatory variables
(called independent variables). In fact, the linear regression estimates the coefficients of the
65
linear equation, involving one or more independent variables that best predict the value of
the dependent variable (Norušis 2000). The statistical software package SPSS® 10.0 (SPSS
for Windows 1999) was used to perform these multivariate analyses (based on a stepwise
method for variable selection).
In these analyses, the variables to be explained were HPC and atypical bacteria counts and
total THM levels. The development of multivariate regression models was carried out for
each of these dependent variables for data from the following locations: the chlorination
facility outlet, the distribution system (average of central part and system extremity values),
and the distribution system extremity. Raw water quality and/or operational parameters
(i.e., variables) were used to explain the chlorination facility outlet water quality. Similarly,
chlorination facility outlet variables were used to explain distribution system and extremity
water quality. The successful models (i.e., those that gave significant results; P<0.10) are
shown in Table 2.4.
Multivariate analyses yielded interesting descriptive models. First, it must be noted that
models related to THMs provided better results (higher R2 giving higher explained variance
ratios) than those related to HPC bacteria. A possible explanation involves the very discrete
nature of microbial dissemination within water distribution lines (presence in bulk water,
attached to pipe wall, presence within corrosion tubercles). No significant multivariate
model was found to explain atypical bacteria presence in the studied utilities, even though
some variables (e.g., temperature, UV254 nm) showed significant correlations on a
bivariate basis. This is possibly linked to the fact that this group of micro-organisms is a
complex mixture of species (as mentioned earlier) for which the determining factors may
be various, so that no one factor materializes as vital for all species.
On the whole, HPC bacteria presence at chlorination facility outlets was relatively well
explained by variables bearing on the natural logarithm of HPC bacteria counts in raw
water, and occasionally, NOM-related variables (UV254 nm, TOC) and pH. It is surprising
66
Table 2.4. Summary of multivariate analyses Independent variables included in the model
p* Dependent variables n† AdjustedR2‡ P§
Models relating to nonproblematic utilities
HPC_raw_water PH_raw_water TOC_raw_water
0.005 <0.001 <0.001
Ln_HPC_facility 15 0.79 <.001
Log_HPC_facility pH_facility
0.022 0.047 Ln_HPC_distribution system 15 0.42 .012
HPC_facility pH_facility
0.047 0.089 Ln_HPC_extremity 15 0.32 .034
No significant variable n/a‼ Total_THMs_facility 19 n/a n/a
Total_THMs_facility Free_chlorine_facility UV254_facility
<0.001 0.009 0.019
Total_THMs_distribution system 19 0.86 <.001
Total_THMs_facility Free_chlorine_facility UV254_facility
<0.001 0.002 0.030
Total_THMs_extremity 19 0.88 <.001
Models relating to problematic utilities
UV254_raw_water HPC_raw_water
0.002 0.096 Ln_HPC_facility 21 0.41 .002
No significant variable n/a Ln_HPC_distribution system 21 n/a n/a
No significant variable n/a Ln_HPC_extremity 21 n/a n/a
UV254_raw_water TOC_raw_water
0.025 0.097 Total_THMs_facility 29 0.70 <.001
Total_THMs_facility UV254_facility
<0.001 0.005 Total_THMs_distribution system 29 0.85 <.001
UV254_facility Total_THMs_facility
<0.001 0.002 Total_THMs_extremity 29 0.83 <.001
* Significance level for the variable § Significance level for the model † Number of cases ‼ Not applicable ‡ Pearson determination coefficient
67
to note that raw water temperature did not appear among the significant variables. This may
be explained by the relatively low variability of water temperature during the period under
study. It is interesting to point out that disinfectant-related variables (chlorine dose, free
residual chlorine) appeared in most models relating to nonproblematic utilities, but in none
of those bearing on problematic utilities. The chlorine dose appeared in the initial model,
explaining the logarithm of HPC bacteria counts in raw water for nonproblematic utilities,
but when TOC was introduced, the dose was removed. The model improved with TOC
replacing the chlorine dose, but the latter showed a significant bivariate correlation with the
logarithm of HPC bacteria. So, it is obvious that the dose plays a major role, even if it does
not appear in the final model. It is also understandable that the chlorine dose and the TOC
are antagonistic, since the former kills micro-organisms, whereas the latter contributes to
their nutrition. UV254 nm appeared in all models relating to problematic utilities, which
suggests that this parameter, reflecting NOM reactivity, may be much more critical for this
group of utilities although its mean value appears lower than for nonproblematic utilities.
For average total THMs within a distribution system and at its extremity, the prevailing
explanatory factors in nonproblematic utilities are total THMs, free residual chlorine, and
UV254 nm (all at the facility outlet). In fact, a study by Vinette (2001) with three large
utilities demonstrated that up to 50 percent of total THMs present in distribution system
could already be formed in water leaving the treatment plant or chlorination facility.
However, in problematic utilities, only total THMs and NOM-related variables appeared.
The absence of residual chlorine in these models may be explained by low variability of
this variable in problematic utilities. As for total THMs at the facility outlet, they are well
explained by raw water NOM-related variables.
The implications of these models in terms of distribution system management are the
following: the nonproblematic utilities should place more emphasis on chlorine doses and
residuals by applying appropriate doses and maintaining adequate residuals. In fact, utilities
of this group tend to apply too much chlorine. Although this allows effective control of
distribution system microbial flora, it may generate bad tap water taste (chlorine taste) and
result in a relatively high potential for DBP formation. Conversely, in problematic utilities
better management of chlorination doses and residuals would probably improve
68
microbiological water quality by achieving better control of micro-organisms within the
distribution mains. Better protection of source water would also allow these utilities
increased control over NOM-related water quality parameters (especially UV254 nm),
which appear critical to them, even though average values for these parameters are below
those of nonproblematic utilities. The issue about controlling NOM is not easy and may
appear really impractical compared to simply installing some sort treatment for example,
but it does make sense to protect water sources, to the extent possible, from any kind of
pollution where conditions for that exist and appear adequate. To end, controlling man-
made wastes and wastes originating from human-directed activities (like those related to
agricultural land use) remains an effective preventive measure that both utility groups
should implement.
2.5. Conclusions The results of this investigation effectively demonstrate that problematic utilities (defined
as having recurrent occurrences of coliforms based on historical regulatory information)
have lower overall microbiological water quality from the plant to the distribution
extremity. Indeed, for all of the studied parameters that characterize treated and distributed
water quality, except for THMs, the situation is better in nonproblematic utilities. During
the time period of this study, all observed violations of the 2001 QDWR occurred in
problematic utilities (three times for HPC bacteria, once for atypical bacteria counts).
The average applied chlorine doses appeared only slightly different between the two groups
of utilities. However, significant differences in free residual chlorine levels were found
between them all along the distribution system. The study results suggest that maintaining
average residual chlorine in problematic utilities comparable to those used in
nonproblematic utilities (i.e., about 0.7-0.8 mg/L at the facility outlet, and 0.3-0.5 mg/L at
distribution system extremity) would likely bring about significant changes in
microbiological water quality. It is noteworthy that significantly higher concentrations of
THMs were observed in nonproblematic utilities.
69
Because of the characteristics of the raw waters used by the ten investigated utilities,
nonproblematic utilities appear to be able to successfully deal with the challenge of
efficient and simultaneous control of the acute disease risk (represented by pathogenic
micro-organisms) and the chronic health hazard linked to DBPs, even if measured THMs
were higher than those in problematic systems.
Univariate (means tests) analyses indicated that differences in distributed water quality
between problematic and nonproblematic utilities are related to applied chlorine doses and,
to a much greater extent, to HPC bacteria counts and free residual chlorine. As for
multivariate models, they indicated that in terms of distributed water quality management
priorities, nonproblematic utilities should devote more attention to appropriate, balanced
disinfection practices and avoid continually overestimating the microbial risk. This would
allow them to serve their customers with safe and palatable drinking water with a much
lower incidence of chronic health hazards. Problematic utilities need to achieve better
control of UV254 nm and TOC through adequate water source protection, combined with
an important increase of chlorine doses and residuals. If these conditions were fulfilled,
they could attain high, sustainable water quality standards.
The 2001 QDWR require that all surface water utilities conduct at least a filtration prior to
chlorination. Most of the ten utilities chosen for this study are not typical surface water
utilities. Eight of them obtain raw water halfway between surface and groundwater, i.e.,
from surface wells. Thus, these utilities do not fall directly into the category for which
filtration is required. Therefore, they will have to scientifically demonstrate that they
possess the technical and operational capabilities to produce water that consistently meets
the new provincial standards without filtration. Understanding the parameters identified
herein as explaining differences between nonproblematic and problematic utilities, as well
as those identified as explanatory variables in multivariate analyses, may help these
utilities, especially problematic ones, to find ways to comply with the 2001 QDWR
standards. Nevertheless, the situation obviously will require significant readjustments in
disinfection practices, and may necessitate hiring qualified operators. The utilities that will
undoubtedly have to install filtration (e.g., the two utilities that draw their raw water from
70
lakes), should devote significant attention to CT requirements and post-chlorination THM
levels.
From a strict public health standpoint, it must be mentioned that water distributed by
problematic utilities selected in this study does not necessarily present more of a threat than
the water served by nonproblematic utilities. In fact, microbiological parameters considered
in this study (i.e., total coliform, HPC and atypical bacteria) are essentially hygienically
relevant and do not represent a real or direct disease risk, since it is recognized that these
organisms are not normally pathogenic. Thus, more attention must be given to the potential
relationships that may exist between the presence of these bacteria and the potential
presence of real pathogens such as parasites, viruses and others.
In the future, the task of maintaining water quality that corresponds at all times to
increasingly stringent standards will continue to be very challenging for small utilities,
since they are handicapped by technical, managerial and financial deficiencies.
2.6. References APHA-AWWA-WEF. 1998. Standard methods for the examination of water and wastewater. 20th Edition.
American Public Health association, 1015, 15th Street NW, Washington D.C. 20005-2605. Bellar, T.A., Lichtenberg, J.J., and Kroner, R.C. 1974. The Occurrence of organohalides in chlorinated
drinking water. J. Am. Water Works Assoc. 66: 703. Carter, J.T., Rice, E.W., Buchberger, S.G., and Lee, Y. 2000. Relationship between levels of heterotrophic
bacteria and water quality parameters in a drinking water distribution system. Water Research 34: 1495–1502.
Connell, G. F. 1996. The chlorination/chloramination handbook. Water Disinfection Series. American Water Works Association, Denver, CO.
Fowle III, J.R., and Kopfler, F.C. 1986. Water disinfection : microbes versus molecules – an introduction of issues. Environmental Health Perspectives 69: 3–6.
Gouvernement du Québec. 1984. Règlement sur l’eau potable. Éditeur officiel du Québec, Québec. 7 p. Gouvernement du Québec. 1997. L’eau potable au Québec. Un second bilan de sa qualité : 1989–1994.
Ministère de l’Environnement et de la Faune, Québec. 36 p. Gouvernement du Québec. 2001. Règlement sur la qualité de l’eau potable. Ministère de l’Environnement,
Québec. 19 p. Haas, C.N. 1999. Benefits of employing a disinfection residual. Journal of Water SRT—Aqua 48: 11–15. Krasner, S.W. 1999. Chemistry of disinfection by-product formation. In: Formation and control of
disinfection by-products in drinking water. P.C. Singer (ed.), AWWA, pp. 27-52. LeChevallier, M.W., Schulz, W.H., and Lee, R.G. 1990. Bacterial nutrients in drinking water. In: Assessing
and controlling bacterial regrowth in distribution systems. AWWARF (ed.), pp. 143–201. American Water Works Association Research Foundation, Denver, CO.
LeChevallier, M.W., Welch, N.J., and Smith, D.B. 1996. Full-scale studies of factors related to coliform regrowth in drinking water. Applied Environmental Microbiology 62: 2201–2211.
71
Levallois, P. 1997. Qualité de l’eau potable et trihalométhanes. Bulletin d’Information en Santé Environnementale (BISE) 8: 1–4.
McCoy, W.F., and Olson, B. H. 1986. Relationship among turbidity, particle counts and bacteriological quality within water distribution lines. Water Research 20: 1023–1029.
Milot, J., Rodriguez, M.J., and Sérodes, J. 2000. Modeling the susceptibility of drinking water utilities to form high concentrations of trihalomethanes. Journal of Environmental Management 60: 155–171.
Norušis, M.J. 2000. SPSS® 10.0 Guide to data analysis. Prentice-Hall, Inc. Upper Saddle River, New Jersey 07458.
OMS 1994. Directives de qualité pour l’eau de boisson : recommandations. Deuxième édition, volume 1. Genève, Suisse.
Payment, P., Berte, A., Prévost, M., Ménard, B., and Barbeau, B. 2000. Occurrence of pathogenic microorganisms in the St. Lawrence River (Canada) and comparison of health risks for populations using it as their source of drinking water. Canadian Journal of Microbiology 46: 565-576.
Pipes, W.O. 1982. Introduction. In: Bacterial indicators of pollution, pp. 1-9. CRC Press. Putnam, W.S., and Graham, J.D. 1993. Chemicals versus microbials in drinking water: a decision sciences
perspective. J. Am. Water Works Assoc. 85: 57–61. Reasoner, D.J. 1990. Monitoring heterotrophic bacteria in potable water. In: Drinking Water Microbiology:
Progress and Recent Developments. G. A. McFeters (ed.), New York, Springer-Verlag, pp.453-473. Rodriguez, M.J., Milot, J., Sérodes, J.-B., and Montixi, M.-D. 1999. A New modelling approach to simulate
chlorine demand and trihalomethane formation in drinking water. Proceedings of the American Water Works Association Annual Conference, Chicago, Ill. 20-24 June.
Rodriguez, M.J., and Sérodes, J.-B. 2001. Spatial and temporal evolution of trihalomethanes in three water distribution systems. Water Research 35: 1572–1586.
Rodriguez, M.J., Coulibaly, H.D., and Banville, J. 2002. Strategies for ensuring a safe drinking water in small utilities of Quebec (Canada). Proceedings of the American Water Works Association Annual Conference and Exposition (ACE), New Orleans, La. 16-20 June.
Rook, J.J. 1974. Formation of haloforms during chlorination of natural waters. Water Treatment and Examination 23: 234-243.
Sérodes J.B., Rodriguez, M.J., and Ponton, A. 1998. Development and on-site evaluation of a decision-making tool for chlorine disinfection dose and residual control. Presented at the 8th National Conference on Drinking Water, Canadian Water and Wastewater Association (CWWA), Quebec City, Quebec, Canada. 28-30 October.
SPSS for Windows 1999. Release 10.0.0 standard version. Copyright® SPSS Inc. USEPA. 1989. National primary drinking water regulations: filtration, disinfection, turbidity, Giardia
lamblia, viruses, Legionella, and heterotrophic bacteria. Final Rule. Fed. Reg., 54:124:27486. USEPA. 1993. Preventing waterborne disease: a focus on EPA’s research. Office of Research and
Development (EPA/640/K–93/001), Washington, DC 20460. USEPA. 1998a. National primary drinking water regulations: disinfectants and disinfection by-products.
Final Rule. Fed. Reg., 63:241:69389. USEPA. 1998b. National primary drinking water regulations: interim enhanced surface water treatment rule.
Fed. Reg., 63:241:69477. USEPA. 2000. National primary drinking water regulations: groundwater rule. Proposed Rules. Fed. Reg.,
65:91:30194. van der Kooij, D., van Lieverloo, J.H.M., Schellart, J., and Hiemstra, P. 1999. Maintaining quality without a
disinfectant residual. J. Am. Water Works Assoc. 91: 55-64. Vinette Y. 2001. Évolution des trihalométhanes dans divers réseaux de distribution d'eau potable
municipaux. Mémoire de maîtrise en Génie Civil, Université Laval.
CHAPTER 3 Impact of technical and human factors on water
quality in ten small Quebec utilities Overview. The spatial and temporal variation of drinking water quality in ten small
Quebec municipal utilities examined in the second chapter of this study has brought a
number of precious indications as for factors, i.e. parameters, potentially responsible for the
difference observed in distributed water quality between nonproblematic and problematic
utilities on a historical basis, while also enabling to document the water quality in studied
utilities from the source to the consumer’s tap. This second stage of the present study was
very important, since it allowed searching for potential causes of observed historical
differences directly in water that currently reaches the local consumers. It allowed as well
identifying factors upon which utility managers may act to improve the quality of
distributed water in each of the two opposed utility groups (i.e., nonproblematic vs.
problematic).
Despite those all-interesting results, the second chapter obviously left aside certain
potential explaining factors. The latter are factors relating to the whole range of operational
(i.e., disinfection-related), as well as infrastructure and maintenance characteristics, to go
with human and organizational factors specific to each of the studied utilities. So, to make
the study complete, it appeared essential to consider exploring all of the aforementioned
characteristics, as potential factors explaining both current and historical water quality in
the studied utilities. This is what is being done in the next and last chapter of the present
study.
Abstract. Ten small Quebec municipal drinking water utilities have been studied as for
their operational, infrastructure, and maintenance characteristics, along with human and
organizational factors governing the utilities’ life. All of these utilities use surface water or
groundwater under the direct influence of surface water and apply chlorination as the only
treatment before distribution. The ten utilities were subsequently divided into two groups:
four utilities that had never or rarely served water infringing upon the provincial drinking
73
water microbiological standards (relating to fecal and/or total coliform bacteria), and six
utilities that very often infringed upon said standards. The objective of this study was to
investigate the impact of the utility operational, as well as infrastructure, and maintenance
characteristics on current distributed water quality in small utilities and to explore the
impact of human and organizational factors, which govern the principal utility manager's
action, on historical water quality in the same utilities. The study includes three distinctive
parts: the first one is a portrait of studied utilities’ operational, infrastructure, and
maintenance characteristics; the second part is devoted to development of indicators of
performance for the same utilities, whereas the last part deals with human and
organisational factors. The portrait revealed interesting trends in terms of distinctive
features between nonproblematic and problematic utilities. Utility performance indicators
were systematically better for the nonproblematic group as compared to the problematic
one, with a major input from disinfection-related performance sub-indicators, and those
bearing on infrastructure and its maintenance. As for human and organizational factors,
they allowed highlighting such issues like educational background, supplementary training,
experience, awareness of and preparedness to take up new challenges, and support from
local authorities.
Key words: drinking water, water quality, small utilities, performance indicators, human
factor, Quebec
Résumé. Dix petits systèmes municipaux de distribution d’eau potable au Québec ont été
étudiés en ce qui a trait aux caractéristiques d’opération, de même qu’à celles liées à
l’infrastructure et à sa maintenance, auxquelles ont été joints les facteurs humains et
organisationnels régissant la vie de ces systèmes. Tous ces systèmes utilisent de l’eau de
surface ou de l’eau souterraine sous influence directe de l’eau de surface et pratiquent une
simple chloration. Les dix systèmes furent par la suite répartis en deux groupes : quatre
systèmes qui n’ont jamais ou ont rarement distribué de l’eau dérogeant aux normes
microbiologiques provinciales relatives à l’eau potable (en ce qui a trait aux coliformes
fécaux et/ou totaux) et six systèmes qui ont très souvent dérogé aux dites normes.
L’objectif de cette étude était d’explorer l’impact des caractéristiques opérationnelles, de
74
même que celles de l’infrastructure, et de la maintenance sur la qualité courante de l’eau
distribuée par ces petits systèmes, et de sonder l’impact de facteurs humains et
organisationnels liés à la personne du gestionnaire principal sur la qualité historique de
l’eau desservie par les mêmes systèmes. L’étude inclut trois parties : la première est un
portait des caractéristiques d’opération, de l’infrastructure et de la maintenance ; la
deuxième est consacrée au développement d’indicateurs de performance pour les petits
systèmes ; quant à la troisième, elle traite des facteurs humains et organisationnels. Le
portrait a révélé des tendances intéressantes en terme de traits distinctifs entre systèmes
non-problématiques et problématiques. Les indicateurs de performance des systèmes étaient
systématiquement meilleurs dans le groupe des non-problématiques comparativement à
celui des problématiques, avec un apport crucial des sous-indicateurs de performance de la
désinfection et de ceux ayant trait à l’infrastructure et à sa maintenance. Pour ce qui est des
facteurs humains et organisationnels, ils ont permis de mettre en exergue des aspects tels
que la formation principale, la formation complémentaire, l’expérience, la conscience des
nouveaux défis et du niveau de préparation requis pour y faire face, et enfin l’appui des
autorités locales.
Mots-clés : eau potable, qualité de l’eau, petits systèmes, indicateurs de performance,
facteur humain, Québec
3.1. Introduction There are about 1,000 small municipal drinking water utilities (i.e., serving 10,000 people
or less) in Quebec (Gouvernement du Québec 1997). Utilities of that size are the most
numerous in the province. In other respects, it is well known that small utilities often lack
adequate technical, managerial, and financial capacity (USEPA 1999).
In Quebec, small municipal utilities that have chlorination as the only treatment applied to
drinking water before its distribution to their customers had been found most frequently
violating provincial drinking water standards regarding microbiological quality
(Gouvernement du Québec 1997). This has been mentioned by the Quebec Ministry of
75
Environment (QME) based on 1984 Quebec drinking water regulations (QDWR) follow-up
information (Gouvernement du Québec 1984), before the publication of new QDWR in
June 2001. These new QDWR have already affected or will affect infrastructure needs and
human resources in practically all small Quebec drinking water utilities. This opinion is
based on new, very stringent, microbial inactivation and (or) removal requirements, not to
mention personnel training and many other new requirements (Gouvernement du Québec
2001).
The role of the distribution system infrastructure in serving drinking water with
irreproachable quality is vital. For instance, storage tanks (Opferman et al. 1995) and
distribution mains physical and chemical properties (LeChevallier et al. 1990) play a big
role in the possibility for utility managers to maintain the quality unchanged from the point
of treatment to the point of consumption. In recent years, numerous publications have
focused on the impact of some distribution system infrastructure components (e.g., pipe
material, storage tanks) on consumer’s tap water quality (Opferman et al. 1995; AWWA
1998). However, very few of those studies considered the impact of the supply system as a
whole (including source characteristics, treatment plant, storage tanks, distribution pipes,
and all other components). Similarly, very few studies considered the impact of the
characteristics of utility management by the principal operator/manager (henceforward:
manager), that is the organizational and human factors. In addition, interest in these aspects
has been much higher in median and large utilities than in small ones.
The objectives of this study are: 1) to investigate the impact of the system infrastructure as
well as the operational and maintenance characteristics on the distributed water quality in
small utilities; and 2) to explore the impact of human and organizational factors tied to the
utility manager.
This case study bears on ten small utilities of the province of Quebec (Canada). To
determine their significance, utility and human factor characteristics are related to current
and historical water quality in the distribution system. Utility characteristics are integrated
through performance indicators, while human and organizational factors are analyzed on a
qualitative basis.
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3.2. Methodology
3.2.1. Procedure for selecting the ten utilities Based on a Quebec Ministry of Environment (QME) database on regulatory follow-up,
with data for 1997, 1998, and 1999, two types of small utilities were distinguished. The
first type included utilities that had never registered coliform positive samples or had
registered such samples only on extremely rare occasions. The second type encompassed
utilities that often registered coliform positive samples. Based on these remarks, two
concepts were defined: coliform episode and problematic utility. A coliform episode
indicated one or a set of coliform positive samples occurring in a given distribution system
during the three-year period (1997-1999), separated by at least 15 days from any other
coliform positive sample in the same system. A problematic utility was defined as a utility
that registered one or more coliform episodes in at least two of the three reference years.
Consequently, utilities that registered no coliform episode, or had episodes in only one of
the above-mentioned three years, were designated as nonproblematic utilities. It is
important to note that the concerned QME database comprised data from 927 small Quebec
utilities with results of about 65,000 water sample analyses for the above-mentioned three-
year period. It has been noticed that about 25% of the 927 utilities (that is, 230 utilities)
have been experiencing repetitive coliform episodes. It was precisely that fact that led to
the differentiation into “nonproblematic” and “problematic”.
Among utilities appearing in the QME database, ten have been subsequently chosen for the
present study. The selection of these ten utilities was based on the following criteria: 1)
they used either surface water (lake or stream) or groundwater under direct influence of
runoff (surface wells); 2) chlorination was the only treatment applied; 3) for logistic
reasons, they had to be located relatively close (within a radius of about 150 km) to
Quebec-City; 4) the 10 utilities encompassed a group of problematic utilities and a group of
nonproblematic utilities; and 5) utility managers had to be in agreement with the proposed
study and offer to co-operate by favouring easy access to all infrastructure components and
archived water quality data, and being available for interviews. Under these criteria, four
nonproblematic and six problematic utilities were selected.
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First, a study of the spatial and temporal variation of drinking water quality was done in the
ten utilities (see previous chapter; see also Coulibaly and Rodrigez, 2003b). Table 3.1 gives
an overview of some specificities of the studied utilities, along with some data showing
water quality variability all along the distribution systems.
3.2.2. Information about the distribution system infrastructure Information about distribution system infrastructure bore on characteristics like
chlorination plant and machinery, storage tanks, and distribution network (pipelines). To
gather that kind of information, a questionnaire was built up in October 2001 and the
manager of each of the ten utilities was asked to answer its content during a semi-directive
interview with inquiries focused on distribution system components, operational practices
(i.e., disinfection-related variables), and maintenance practices (see Appendix D).
Questions about the distribution system components bore on the presence/absence,
dimensions (or capacity) of some components (e.g., emergency chlorinator, storage tank,
etc.), or the relative importance of some kind of material (e.g., percent of cast iron pipes, of
PVC pipes, etc. in the total length of the distribution lines). Questions about operational
practices were on details like the method of chlorine injection or the frequency of chlorine
residual measurements. As for maintenance practices, they bore essentially on distribution
network flushing and pipe break management. Personal observations made by the authors
during an eight-month field work corresponding to sampling campaign in the ten concerned
municipalities in 2001, as well as all information drawn from local archives or from usual
ordinary talk with respective utility personnel will also be considered.
Table 3.1. Overview of water quality variation in the studied utilities
Utility historical water quality status Raw water quality Distributed water quality
Chlorine residuals (mg/L)‡
HPC bacteria (cfu/mL)‡
Atypical bacteria (cfu/100 mL)‡
Turbidity (ntu)†
TOC* (mg/L)†
Total coliform Bacteria
(cfu/100 mL)†
HPC** bacteria
(cfu/mL)†
Atypical bacteria
(cfu/100 mL)†
Entrance Centre Extremity Entrance Centre Extremity Entrance Centre Extremity
Nonproblematic
II. 1.26 3.20 28 1544 329 1.54 0.76 0.64 8 44 54 1 1 1
III. 0.26 1.36 11 638 161 0.46 0.21 0.21 20 88 82 10 3 5
V. 0.54 0.53 30 526 187 0.57 0.38 0.29 17 24 35 2 0 0
VII. 0.22 2.51 3 106 12 0.18 0.06 0.04 6 31 38 1 1 0
Problematic
I. 1.06 4.16 41 1052 239 0.68 0.02 0.02 10 128 112 15 9 16
IV. 0.50 0.59 17 2212 111 0.61 0.51 0.49 50 56 58 18 13 6
VI. 0.55 0.29 2 886 28 0.44 0.15 0.09 20 32 131 81 0 0
VIII. 0.18 0.84 20 155 91 0.09 0.04 0.07 32 40 43 1 0 0
IX. 0.26 0.85 4 672 84 0.31 0.20 < 0.01 46 86 265 15 16 20
X. 0.14 1.78 5 332 145 0.19 0.02 0.04 9 116 79 2 28 37
† Average of 5 monthly values * Total organic carbon ‡ Average of 5 monthly values at each location ** Heterotrophic plate count bacteria
Table 3.2 shows the main studied characteristics of distribution system operation,
infrastructure, and maintenance.
Table 3.2. Distribution system operational, infrastructure, and maintenance characteristics
System management components Considered characteristics
Chlorination devices Mode of chlorine injection Disinfection effectiveness Usual residual chlorine checkpoints
Operation (disinfection-related)
Frequency of residual chlorine measurement
Utility age Storage tanks Infrastructure Pipe material
Pipe breakage Maintenance System flushing
3.2.3. Information about the human and organizational factors
It is important to recall that all ten studied utilities have chlorination as the only treatment
applied and use surface water or groundwater under the direct influence of surface water.
This fact makes much greater the role and potential impact of an efficient and competent
manager to ensure that these systems constantly serve water of irreproachable quality. So,
human and organizational factors are being considered herein for the ten small municipal
drinking water utilities with regard to the main managerial personnel (see Appendix E).
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The information (or data) collection method used was also a semi-directive interview of the
manager of each of the concerned ten small utilities. This allowed asking all questions that
appeared on a questionnaire at hand while enabling him to tackle his specific issues of
interest. The questionnaire comprised two sections and thirteen clusters of questions (see
Appendix D). The first section contained general information on the manager, whereas the
second section was constituted of inquiries about the distribution system management. The
questionnaire, in its entirety, permitted to inquire about the utility manager’s
socioprofessional characteristics and the organizational factors influencing his work. The
manager’s socioprofessional characteristics encompassed major professional indicators of
competency such as his general education and (or) academic standard regarding the
drinking water field, knowledge of regulatory texts or standards, being up-to-date on the
drinking water industry burning questions, and so forth. As for organizational factors, they
include the manager’s whole working universe (environment), with all of the latter’s
influences and interactions like the manager’s networking capabilities (that is, relationships
with peers, experts, consultancy; subscription to water quality/water resources management
journals, membership of associations or other organizations working in the field of drinking
water, etc.). Organizational factors also include the direct or indirect influences of local
administration (i.e., municipal officials) and its policy in the field of drinking water.
The information collected on human and organizational factors was treated using the
analytical techniques (or methods, processes) of the positivist/postpositivist stance. The
positivist/postpositivist stance (see Denzin 1994; Huberman and Miles 1994; Guba and
Lincoln 1989) may enable linking the analyzed socioprofessional features of each manager
and the whole organizational structure surrounding the utility with its historical water
quality, in terms of causes and effect.
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3.3. Results and discussion
3.3.1. Characteristics of operation, infrastructure, and maintenance The analysis was done in two steps: first, a comparative portrait of the different studied
variables (i.e., characteristics) was drawn up between nonproblematic and problematic
utilities; then, an integration of these variables is carried out through development of utility
performance indicators. Such explanatory indicators may help revealing the potential
contribution of the examined variables in explaining observed differences in the distributed
water quality.
3.3.1.1. Variables on distribution system operation (i.e., disinfection-related)
3.3.1.1.1. Chlorination devices The presence or absence of an emergency chlorinating device (or chlorinator) in the
distribution system was the first disinfection-related variable examined (see Appendix F).
It appeared that such a device was mostly absent in both groups of utilities. However, it
was interesting to note that measures existed (or were planned for near future) wherever the
concerned mechanism was absent among nonproblematic utilities, whereas nothing existed,
nor was planned, to compensate for the absence of emergency chlorinator among the
problematic utilities.
As for the type of chlorinator, devices in the two groups were similar. No manually
chlorinating utility was found among the nonproblematic (there was one among the
problematic). Manual chlorination, obviously, is much less efficient than using a well
calibrated chlorinator, since it can in no way ensure an equitable distribution of the applied
chlorine dose according to water flowrate at any time of the day (or night) like the
chlorinator does. And, this may mean total depletion of chlorine residuals, with subsequent
microbial regrowth or recovery within distribution networks and the potential public health
repercussions of such phenomena. So, the chlorination devices variable is of great
importance, since it probably affects the disinfection effectiveness (i.e., CT value). And,
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indicators of disinfection efficacy to come will sum up potential impacts of this and other
disinfection-related variables.
3.3.1.1.2. Mode of chlorine injection
This operational variable gives another perspective of the question. All nonproblematic
utilities injected the disinfectant according to flowrate, whereas only 2 out of the 6
problematic did so (with 3 of them performing constant injection over time, and the last
one—manually). Chlorinating according to flowrate over time is more efficient than the
other two methods, since it is the only one that permits automatic adjustment of the applied
chlorine dose concurrently to water demand ups and downs (AWWA 1996). Constant
injection, that is, administering the same dose all time, no matter what water demand is,
may result sometimes in very high doses (when demand is low), and other times in too
small doses (when water demand goes up). As for manual chlorination, it is assuredly the
worst one: a daily sudden raise in water chlorine content that steadily fades over time until
total disappearance of chlorine residuals in distributed water before the next dose is applied.
Therefore, the mode of chlorine injection is of great importance too, since it very likely
affects the disinfection effectiveness.
3.3.1.1.3. Disinfection effectiveness The efficacy of drinking water disinfection procedures is estimated using the CT concept.
The CT is a concept that aims at ensuring sufficient contact time (T) and maintenance of
adequate disinfectant residual concentration (C) to attain disinfection objectives set by the
utility designer, guided by water quality standards promulgated by regulatory institutions
(Gouvernement du Québec 2002).
Pathogens contained in source waters must be removed before water is served to
consumers. Microbial cells can be eliminated either by physical removal (i.e., via diverse
filter media) or by chemical inactivation (i.e., using disinfecting agents). According to
83
Gouvernement du Québec (2002), the resulting “log” of cell reduction can be estimated as
follows:
Log of reduction = ∑ physical removals + ∑ chemical inactivations
Since the ten small utilities of this study have no other treatment than disinfection (i.e.,
chlorination), only inactivation can be considered. Furthermore, that situation makes
chlorination the only barrier between potential source water pathogens and the consumer’s
tap. Therefore, it is essential to ensure that that barrier be as effective as it could be. The
disinfection effectiveness is evaluated in terms of “log” of inactivation (Gouvernement du
Québec 2002, USEPA 1999). This value is determined using the following formula:
Log of inactivation = CTavailable / CTrequired
As its name suggests, the CTavailable is the actual CT value measured at the utility by the
designers. As for the CTrequired, it is a value the designer is provided with via tables
compiled by the USEPA (1991 and 1999) that indicates the required CT value to inactivate
1 log of a given microorganism (virus or Giardia or Cryptosporidium) in water with given
characteristics (pH, temperature, etc.) (Gouvernement du Québec 2002).
CTavailable = Cresidual x T10 = Cresidual x Vu/QMAX x T10/T
Where : Cresidual is the disinfectant concentration at the chlorination facility storage tank outlet; QMAX is the peak flowrate at the storage tank outlet; Vu is the useful volume in the storage tank (not the latter’s capacity); and T10/T is the hydraulic efficiency factor Based on these considerations, the following approximate CT values have been calculated
for the utilities at study (see Table 3.3). These CT approximates, calculated using the
relatively limited (primarily for T10/T and secondarily for QMAX) data available with the ten
utility managers, enabled making relative comparisons between nonproblematic and
problematic utilities as for disinfection efficacy.
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Cresidual has been estimated by taking the mean of residual chlorine concentrations recorded
at the facility outlet and the distribution system central part, since there was no sampling
point available directly at storage tank outlets. QMAX was obtained directly with utility
managers, which considered it as equalling the overall power of available distribution
system feed pumps. Vu was considered as equalling 80 percent of the storage tank capacity.
And, very conservatively, the T10/T factor (which varies between 0 and 1) was considered
equalling 0.2 when chlorinated water is stored in a tank before its distribution, and
equalling 0.6 when chlorination is done directly into the water main en route for the
consumer’s tap.
Average CT values for nonproblematic utilities are significantly higher than those recorded
for problematic utilities (229 mg⋅min/L vs 106 mg⋅min/L, respectively). This supports
findings made in previous work (see Coulibaly and Rodriguez 2003b), where disinfection-
related water quality parameters were constantly found better in nonproblematic utilities,
and that, all along the distribution network. If disinfection parameters were always better in
nonproblematic utilities as compared to problematic ones, so it may be logical to presume
that water quality as a whole was better in the nonproblematic group, since there was no
other treatment than chlorination. With chlorination alone, the maximum reasonable
disinfection objective for such utilities appears the 4-log virus inactivation (required by the
2001 QDWR for surface water systems), which is achievable with a CT of 15 to 60
mg⋅min/L for most temperatures according to USEPA (1999). As for the 3-log Giardia
cysts and, especially, the 2-log Cryptosporidium oocysts inactivation (two of the many
other requirements brought in by the 2001 QDWR for surface water systems), they will
necessitate supplementary disinfection, most probably ultraviolet (UV) radiation or ozone
(O3). Note that while chlorine can achieve 3-log Giardia cyst inactivation, the CT
requirement for 3-log inactivation of 100 to more than 300 mg⋅min/L will require high
chlorine doses and (or) long contact times (USEPA, 1999). The performance indicators, to
be addressed later on, will make clearer the differences foreseen.
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Table 3.3. CT-value (mg⋅min/L) approximations for utilities at study
Utility historical water quality status
Cresidual, mg/L
QMAX, m3/min
Vu, m3 T10/T CT, mg⋅min/L
Nonproblematic II. 1.15 1.36 545 0.6 276 III. 0.34 0.55 726 0.2 90 V. 0.48 1.62 2724 0.6 485 VII. 0.12 0.34 908 0.2 64
Problematic I. 0.35 0.55 1090 0.2 139 IV. 0.56 0.90 291 0.2 36 VI. 0.30 0.55 1090 0.6 357 VIII. 0.07 0.38 458 0.6 51 IX. 0.26 0.76 726 0.2 50 X. 0.10 0.90 218 0.2 5
3.3.1.1.4. Usual residual chlorine checkpoints Usual residual chlorine checkpoints give a similar portrait in the two groups. While all
nonproblematic utilities usually check for residuals at the chlorination facility outlet, only 4
out of the 6 problematic ones do likewise. Checking for free chlorine residuals at the
facility outlet is somewhat dictated by present QDWR, since the latter require that utility
managers ensure a minimum of 0.3 mg/L free chlorine concentration at the facility outlet.
Nonetheless, doing that properly is certainly a sign of good management routines.
3.3.1.1.5. Frequency of residual chlorine measurement
All nonproblematic utility managers declared measuring free residual chlorine
concentration at the chlorination facility outlet every day, whereas only half of problematic
utilities mentioned doing so (with the other half measuring it every two days). Since a more
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frequent checking of disinfectant residuals favours timely adjustments of applied doses, this
also points towards better management routines among nonproblematic utilities as
compared to problematic ones.
3.3.1.2. Variables on distribution system infrastructure
3.3.1.2.1. Utility age The first studied infrastructure characteristic was the utility age (see Appendix F). Aging
water mains, especially those made of iron-based material, can cause water quality
deterioration within the distribution network, particularly through corrosion. In addition to
favouring precipitation of metal ions, which can cause coloured water, pipe corrosion may
favour the formation of tubercles within which a biological film can form or cause breaks
in the main, both aspects being favourable conditions for deterioration of microbiological
water quality (LeChevallier et al. 1990). A brief comparison of nonproblematic utilities to
problematic ones according to their age permitted to find out that the average age is higher
for nonproblematic utilities (42 years versus 37.7 years). However, 3 out of the 4
nonproblematic utilities are less than 30 years, whereas only 3 out of the 6 problematic
utilities in that situation. In fact, withdrawing the “extremely aged” utility in each group
(i.e., nonproblematic utility III and problematic utility I) would have made the
nonproblematic group appear significantly younger than the problematic group: average
age of 26 years vs. 33 years. For a better idea of what that represents, it may be helpful to
mention that survey results for medium and large Quebec utilities (Villeneuve and Hamel
1998; Fougères et al. 1998) showed that 65% of them are 35 years old or less. In
comparison, 3 out of the four nonproblematic utilities studied herein are in such a situation,
whereas only half of problematic ones could claim being in that category. However, these
are only general portrait considerations; categorizations and (or) conceptualizations to come
in the indicators portion will be more appropriate for identifying the potential impact of the
age factor on the groups’ historical water quality indicator.
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3.3.1.2.2. Storage tanks Storage tanks may have different types of impact on distributed water quality according to
their physical and (or) chemical properties (Opferman et al. 1995). According to their
internal wall properties, they may improve chlorine contact with bulk water, thereby
enhancing microbial inactivation. However, when tank capacities are big and water demand
low (i.e., water travel time too long), storage tanks could also be locations were chlorine
residuals undergo rapid decay even before water begins its travel through the distribution
network, en route for the consumer’s tap. Based on these considerations, the storage tank
variable was included in the CT variable at the indicator development stage. In other
respects, possessing sufficient storage capacity may appear as a sign of clearsightedness
from the utility designers, in case an emergency strikes (firefighting, draught, important
main breaks, and so forth). Because sufficient data are available only for making
comparisons between the two groups of utilities according to storage tank numbers,
capacities, average storage durations, and storage tanks localization, comments will be
restricted to general portrait aspects at this stage. Thus, all nonproblematic utilities but one
have two storage tanks each, whereas only 2 out of 6 are in that situation among
problematic utilities (see Appendix F). It has been noticed that the nonproblematic group
average tank capacity (875.6 m3) is significantly bigger than the one for the problematic
utility group (604.9 m3). Likewise, the average storage volume per nonproblematic utility
(1532.2 m3) is much more important than the same average per problematic utility (806.6
m3). The average storage duration is the same in the two groups (that is, about 42 hours). It
may be interesting to note that 2 out of the 4 nonproblematic utilities had a storage time of
48 hours or more in comparison to 4 out of the 6 for problematic utilities. As for
information on storage tanks localization, it shows that, in both groups, only half of them
are located at the chlorination facility. This situation may have different consequences
according to the general configuration of each distribution system. Further, conceptualized,
analysis will be done later for exploring the potential impact of storage tank characteristics
on distributed water quality.
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3.3.1.2.3. Pipe material The type of pipes (i.e., cast iron pipe, PVC pipe, etc.) chosen by utility designers and
managers is of great importance in terms of distributed water microbiological and
physicochemical quality. For example, as mentioned earlier, iron-based pipe material may
cause water quality deterioration within the distribution network through corrosion, with its
corollary being coloured water, tubercles and biofilm formation, and even main breaks
(LeChevallier et al. 1990).
Pipe material composition was as follows: 1.2% grey cast iron, 71.4% ductile cast iron,
26.2% PVC, and 1.2% other material—on average for nonproblematic utilities versus
22.8% grey cast iron, 46.7% ductile cast iron, 29.5% PVC, and 1% other material—on
average for problematic utilities (percentage calculated from data shown in Appendix F).
The most important distinction seems to be tied to the proportion of grey cast iron—22.8%
for problematic utilities (that is, exactly 19 times as much as in the nonproblematic group).
Such a proportion appears huge, since grey cast iron pipes, which are being progressively
abandoned (Villeneuve and Hamel 1998; Fougères et al. 1998), are known to be very
sensitive to corrosion, which can be detrimental to distributed water microbiological and
physicochemical quality. Secondarily, the proportion of ductile cast iron is much bigger in
the nonproblematic group than in the problematic one (nearly the double). Ductile cast iron,
especially when coated, is considered a much more resistant material to corrosion than grey
cast iron. As for PVC pipes, their proportion is approximately the same in the two groups.
PVC pipes are not corrodible; however, they are much less resistant to pressure than cast
iron pipes, and have been found to release their own substances in distributed water. On the
whole, the proportion of PVC pipes appears normal in for both groups, and so is the case
for the proportion of cast iron pipes (72.6% for nonproblematic group versus 69.5% for
problematic one), judging by results of a 1999-2000 survey of small Quebec utilities (see
Rodriguez et al. 2002; Coulibaly and Rodriguez 2003a): on average, 63% of the
distribution pipes were made of cast iron, and 28% made of PVC. Further attempts to
characterize the impact of pipe material on tap water quality will be made later through
development of related indicators.
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3.3.1.3. Variables on distribution system maintenance
3.3.1.3.1. Flushing Periodical flushing may be an efficient way to ensure distribution system overall
healthiness, since it makes possible taking out biofilm and corrosion tubercles, both of
which favour drinking water microbiological quality deterioration within distribution lines
(Antoun et al. 1999; Duranceau et al. 1999).
On average, nonproblematic utilities had 1.75 flushing events per year, whereas the
problematic group average was 2.17. Moreover, 4 out of the 6 problematic utilities had at
least 2 flushing events per year, with two utilities doing more; in comparison, none of the
nonproblematic utilities had more than 2 flushing events in any one year. It is at first sight
surprising to see that the higher average flushing number pertained to the group with the
worse water quality record. However, the most important difference may not be in the
number but in the way flushing is performed, the portions flushed (entire distribution
network or only chosen parts of it), at what season(s) flushing is performed, and which are
the reasons that made utility personnel flush the system.
The utility manager’s opinion on distribution network flushing frequency may be
interesting to know, since it gives an indication of his propensity to maintain the status quo
or make changes for the future. It also allows having a relatively good idea of why and how
flushings have been executed in the past. Generally speaking, all managers are rather of the
opinion that distribution system flushing events are not uncommon at their respective
utilities. A proactive stance seemed however to dominate among nonproblematic utilities,
which, on the whole, considered flushing exclusively as a preventive sanitary measure to
consolidate their distribution system overall healthiness. As far as the problematic group of
utilities was concerned, a clearly reactive stance could be foreseen: flushing seemed to be
considered in that case as a curative measure to get rid of repetitive microbial invasions.
That is probably the main reason why problematic utilities performed more flushing than
nonproblematic ones. However historical water quality indicators rather tended to prove
that flushing alone could not solve the problem. And new indicators bearing on that
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variable, among others, will allow for a more realistic estimation of the impact of that
management practice on distributed water quality.
3.3.1.3.2. Main breakage Main breaks are known to be a possible gate for micro-organism and (or) other contaminant
entrance into distribution systems (McDonald et al. 1997; CMHC 1992). This means that
good management of drinking water main breaks could only be beneficial to the ultimate
consumer’s tap water quality. While main breakage rates appear much higher among
problematic utilities as compared to nonproblematic ones (see Appendix F), it is
surprising to note that in both groups, the highest breakage rate pertained to a relatively
young utility (i.e., 28 for the nonproblematic, and 26 for the problematic). The overall
group breakage rate for the nonproblematic utilities was only about 6/100 km/year, whereas
the problematic group recorded more than twice as much (about 14/100 km/year). In other
respects, it is interesting to note that only half of nonproblematic utilities declared having
experienced main breaks in the previous year, whereas 4 out of the 6 problematic ones
acknowledged having had them. Nevertheless, the main breakage rate in both groups might
be considered as not giving serious cause for concern, since, according to McDonald et al.
(1997), main break rate can be considered abnormally high when it exceeds 40/ 100
km/year (none of the ten utilities had this many). The group main break averages
mentioned above (i.e., about 6/100 km/year for the nonproblematic, and about 14/100
km/year for the problematic) also appear rather acceptable, compared to the average for
drinking water distribution systems of Ontario towns (25/100 km/year) (CMHC 1992), the
average for U.S. towns’ distribution systems (about 13/100 km/year) (AWWA 1994), and
the average for 114 small Quebec utilities (about 29/100 km/year) (Coulibaly and
Rodriguez 2003a).
Main break frequency and distribution main leakage did not appear to cause any big
concern among utility managers. This may be easily understandable, since, as seen
previously, the overall nonproblematic and problematic group breakage rates are relatively
low compared to those of other North American utilities. As for water loss through leaks,
its impact seemed decidedly very little, which could mean that the overall portion of
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unaccounted for water was not bigger than 10 to 15%. All of the just said about breaks and
leaks is in total agreement with the relatively young age of both utility groups. Indicators
that will be identified below for main breakage will allow for more conclusive
comparisons.
3.3.2. Indicators of performance for small utilities An abundant literature has been produced about water and environmental quality indices or
indicators over the last three decades (Brown et al. 1970; Ott 1978; Yu and Fogel 1978;
Dunette 1979; Ball et al. 1980; Porcella et al. 1980; Béron et al. 1982; Couillard et
Lefebvre 1986; UNEP 1994; Zandbergen and Hall 1998; Cluis et al. 2001; Lence and
Ruszczynski 2001).
3.3.2.1. Development of performance indicators
Unlike usual water quality indices that are generally intended for characterizing a variable’s
‘‘state of being’’ in relation to a specified use (Laroux et Weber 1994), the performance
indicators that are being developed herein will be oriented towards explaining a situation or
demonstrating a phenomenon. As a matter of fact, these indicators will aim at explaining
why the quality of the distributed water is better in nonproblematic utilities than in
problematic ones (that is, the historical water quality), thereby demonstrating the impact of
a number of crucial variables on the current (i.e., recent) water quality.
As indicated by Béron et al. (1982), for the identification of good indicators, it is better to
stick to a relatively limited number of crucial variables, rather than trying to encompass all
variables that may influence the phenomenon being characterized. Based on these
considerations, a number of variables have been selected from those described in the last
chapter in order to develop the indicators. The selected variables are shown in Table 3.4.
Because of normally close relationships between some of the above-mentioned variables, a
number of them have been considered as having their potential impact already expressed
through connected variables that were retained for indicator development. As an example,
the CT variable encompassed considerations for temperature, pH, free chlorine residual,
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and storage tank characteristics. The last named parameters or characteristics contributed
either directly or indirectly to the CT value computation. In such cases, only the most
“comprehensive” variable (e.g., the CT value) is retained. All individual variables have
been conferred a weight, according to the relative importance of each of them based on
pertinent literature indications (e.g., Béron et al. 1982; Couillard and Lefebvre 1986) and
the concrete statistical levels of significance exhibited by the water quality, as well as
operational and maintenance parameters, in the same small utilities in the two previous
chapters (see also Coulibaly and Rodriguez 2003a,b). The parameters that exhibited the
strongest significance in those chapters (e.g., disinfection-related ones) have been given the
biggest weights.
As shown in Table 3.4, four kinds of parameters or variables have been retained for the
development of indicators. First, an environmentally relevant variable was retained, which
bears on the agricultural land use on the territory of the ten municipalities hosting the water
utilities. This variable was taken from the first chapter. Second, five raw water quality
variables were also retained from a recent sampling campaign in the same ten utilities (see
second chapter). Third, three disinfection-related variables were chosen from the same
sampling campaign. Fourth, four variables bearing on infrastructure and maintenance
characteristics were selected (Table 3.4).
A number of major raw water characteristics have been included as variables in the
determination of performance indicators. This is justified by the primary importance of
source water quality for the studied utilities since they apply no other treatment than
chlorination. The absence of sophisticated treatment (e.g., coagulation, flocculation,
settling, filtration) makes the removal of natural organic matter and potential parasite cysts
or oocysts quasi impossible. Thus, the capacity of such utilities to serve good quality water
is much more impacted on by source water quality than it is for larger utilities.
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Table 3.4. Variables selected for sub-indicators and indicators and their relative weights (wi)
Variable groups Variables Weight
Agricultural land use Agricultural pressure (P2O5) 0.05
TOC 0.03 Turbidity 0.03 Total coliform bacteria 0.05 HPC bacteria 0.02
Raw water quality
Atypical bacteria 0.02
CT value 0.40 Frequency of residual chlorine checking 0.12 Disinfection-related
(or operational) Appropriateness of residual chlorine checkpoints
0.06
Utility age 0.04 Pipe material 0.08 Pipe breakage 0.06
Infrastructure and maintenance
System flushing 0.04
For indicators development, the procedure used was the following. First, four explanatory
“sub-indicators” have been identified. These sub-indicators corresponded to the four
variable groups mentioned in Table 3.4. The four sub-indicators will be used to calculate a
performance indicator for each of the ten utilities at study. Then, overall performance
indicators are determined for both nonproblematic and problematic utilities. Finally, the
two resulting overall indicators are compared to each other, and then put in relation with
the recent distribution water quality (generated in 2001), which is represented by an
indicator based on variables shown in Table 3.5. Weights of this table have been
determined based on the same criteria than for Table 3.4.
For this study, the indicator computation method to be used is the weighted additive one.
This method has been preferred to others (e.g., weighted multiplicative method) because it
allows a linear transformation of performance points into primary indicators. Most
94
importantly, the weighted additive method, which is based on arithmetic mean, will allow
avoiding giving to much importance to low performance scores. So, as an example, this
method is much less severe than the weighted multiplicative method (based on geometric
mean) (Couillard and Lefebvre 1986). The weighted additive method proceeds as follows:
the parameter (or variable) values are transformed into performance scores (see Appendix
G for detailed explanations of how that procedure was carried out in this study), and the
latter are weighted and added up to give a unique value (Yu and Fogel 1978; Ball et al.
1980; Béron et al. 1982; Couillard and Lefebvre 1986).
Table 3.5. Variables used for tap water quality indicators and their relative weights (wi)
Variables Weight Residual chlorine in tap water 0.5 HPC bacteria in tap water 0.2 Atypical bacteria in tap water 0.3
The general formula utilized for computations is the following:
n Ip = ∑ wiγi = w1γ1 + w2γ2+ … + wnγn (Equation 1) i=1 Where: Ip is the utility performance indicator (weighted additive indicator); wi is the weight for the ith variable; γi is the performance score of the ith variable; n is the number of variables.
As detailed in Appendix G, the performance levels vary from 0 to 100 in terms of
performance points, which generally correspond to given percentile values. Table 3.6
shows the performance scores on all considered variables for utilities at study.
Using the Equation 1, all sub-indicators have been computed (Table 3.7). Adapting
literature examples (e.g., Béron et al. 1982) to the specific nature of the variables and the
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objectives of the study, the following performance significance scale has been defined for
sub-indicators and indicators: 0 through 20 ⎯ E; >20 and ≤40 ⎯ D; >40 and ≤60 ⎯ C;
>60 and ≤80 ⎯ B; >80 and ≤100 ⎯ A (Table 3.8 and Table 3.9). This scale has been made
very conservative due to the empirical nature of most of variables (e.g., pipe age, main
breaks). For utility performance sub-indicators determination, the amount of performance
points on each variable was multiplied by this variable’s weight and added to the weighted
performance points of the other variables pertaining to the same sub-indicator. Then, the
resulting weighted sum was divided by the possible maximum weighted amount of points
available on that sub-indicator and multiplied by 100. As for the utility performance
indicator, it was computed by adding up the weighted values of the four sub-indicators by
the corresponding variable group weight.
3.3.2.2. Analysis of the indicator results The agricultural land use sub-indicator demonstrated a relatively good impact on tap water
quality indicator (Table 3.7 and Table 3.8). Of the four very good performances (i.e., score
A) recorded for that sub-indicator, three resulted in acceptable current tap water quality
indicator or better. On the other hand, none of the four utilities that had poor or very poor
performances on that sub-indicator was found with high current tap water quality indicator
(i.e., very good or good performance). Of the nine utilities that recorded the maximum level
of performance on the raw water quality sub-indicator (i.e., 100 points), none had that
much performance as current tap water quality indicator; instead, three of them exhibited
poor or very poor performance in terms of current tap water quality indicators. For the
disinfection-related sub-indicator (by far the most important one, since these utilities
applied no other treatment), only one out of the four utilities that recorded a very good or
good performance did not have at least an “acceptable” performance on current tap water
quality. Of the six utilities that had ‘‘acceptable’’ performance or less on that sub-indicator,
three exhibited poor or very poor performance on current tap water quality. As for the
infrastructure and maintenance sub-indicator, it also showed a positive impact on the
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Table 3.6. Relative level of performance (γi ) of each utility on the considered variables
Small municipal utilities Variables I II III IV V VI VII VIII IX X
Agricultural pressure (P2O5) 100 50 100 100 100 50 25 25 0 0 TOC of raw water 25 50 75 100 100 100 50 100 100 75 Turbidity of raw water 75 75 100 100 100 100 100 100 100 100Total coliform bacteria in raw water 75 100 100 100 100 100 100 100 100 100HPC bacteria in raw water 50 25 75 0 75 75 100 100 75 100Atypical bacteria in raw water 50 0 50 75 50 100 100 75 75 75 CT value 50 75 50 25 100 100 25 25 25 0 Frequency of residual chlorine checking
50 100 100 50 100 50 100 100 100 100
Appropriateness of residual chlorine checkpoints
50 50 50 100 50 50 50 50 50 50
Utility age 25 75 0 75 75 75 75 50 50 75 Pipe material 75 100 100 100 100 100 100 50 100 100Pipe breakage 25 75 75 75 100 0 100 100 75 100System flushing 100 100 100 100 50 50 100 50 100 100 Residual chlorine in tap water 25 100 25 75 50 25 0 0 25 0 HPC bacteria in tap water 50 75 50 75 100 50 100 75 0 50 Atypical bacteria in tap water 50 100 100 50 100 0 100 100 50 25
current tap water quality indicator, as only two of the eight utilities that recorded either very
good or good performance on that sub-indicator exhibited poor performance on current tap
water quality. At the same time, all of the two utilities that did not have more than
‘‘acceptable’’ performance on that sub-indicator showed poor performance on current tap
water quality. As for utility performance indicator and current tap water quality indicator,
they will be commented below, using Figure 3.1, Figure 3.2, and Figure 3.3.
Using the earlier mentioned historical water quality indicator (i.e., nonproblematic vs.
problematic), overall performance indicators have been identified for the two groups of
utilities (Table 3.9). The overall performance indicators corresponding to the two stances of
the historical water quality indicator were obtained by taking the non-weighted average of
the four sub-indicator values (see Table 3.7) for each of the two groups of utilities, then
weighting them by the corresponding variable group weight and adding them up. The
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current overall tap water quality indicators have been calculated using the same procedure.
And, the same 0 to 100 scale, as for Table 3.8, was used to qualify utility group levels of
performance.
Table 3.7. Identified sub-indicators and indicators of performance for individual utilities (real values)
Utility sub-indicators and indicators of performance
Small municipal utilities
I II III IV V VI VII VIII IX X Agricultural land use sub-indicator 100 50 100 100 100 50 25 25 0 0 Raw water quality sub-indicator 58 62 85 83 90 97 90 97 93 92 Disinfection-related sub-indicator 50 78 61 38 95 84 43 43 43 26 Infrastructure and maintenance sub-indicator
57 89 75 89 86 59 95 64 84 95
Utility performance indicator 55 76 69 59 92 79 61 55 57 50 Current tap water quality indicator 37 95 52 67 75 22 50 45 27 17
Table 3.8. Identified sub-indicators and indicators of performance for individual utilities (interpreted values)
Utility sub-indicators and indicators of performance
Small municipal utilities
I II III IV V VI VII VIII IX X Agricultural land use sub-indicator A C A A A C D D E E Raw water quality sub-indicator C B A A A A A A A A Disinfection-related sub-indicator C B B D A A C C C D Infrastructure and maintenance sub-indicator
C A B A A C A B A A
Utility performance indicator C B B C A B B C C C Current tap water quality indicator D A C B B D C C D E
A= Very good performance; B= Good performance; C= Acceptable performance; D= Poor performance; E= Very poor performance
There are many interesting comments to make about Table 3.9. First, all overall sub-
indicators but one favour the nonproblematic group of utilities. The only one in favour of
the problematic group is the raw water quality overall sub-indicator. Although the
nonproblematic group also performs well on that sub-indicator, this important remark
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Table 3.9. Recapitulation of developed indicators of performance
Nonproblematic* Problematic* Utility group sub-indicators and indicators of performance
Indicator values
Utility group sub-indicators and indicators of performance
Indicator values
Agricultural land use overall sub-indicator
69 B Agricultural land use overall sub-indicator
46 C
Raw water quality overall sub-indicator
82 A Raw water quality overall sub-indicator
87 A
Disinfection-related overall sub-indicator
69 B Disinfection-related overall sub-indicator
47 C
Infrastructure and maintenance overall sub-indicator
86 A Infrastructure and maintenance overall sub-indicator
75 B
Overall performance indicator
75 B Overall performance indicator
59 C
Current overall tap water quality indicator
68 B Current overall tap water quality indicator
36 D
* Historical water quality indicator A = Very good performance; B = Good performance; C = Acceptable performance; D= Poor performance
furnishes a big support to comments made in the last the chapter about the fact that
differences seen in current and historical tap water quality between the two utility groups
probably have their main causes inside the distribution system, not in the source water. In
other respects, it is interesting to notice that the problematic group of utilities performs
relatively well on the infrastructure and maintenance overall sub-indicator, only slightly
less than the nonproblematic group. That indicates that infrastructure and maintenance are
in good condition in the nonproblematic and problematic group alike. However, when it
comes down to the agricultural land use overall sub-indicator and, especially, to the
disinfection-related overall sub-indicator, the situation is unequivocally in favour of the
nonproblematic group of utilities. It appears more and more probable that, for current tap
water quality, the disinfection-related overall sub-indicator is the central explaining factor
of the overall much better situation of the nonproblematic group of utilities as compared to
the problematic group. As for the overall performance indicator and current overall tap
water quality indicator, they are commented beneath, along with utility performance
indicator and current tap water quality indicator.
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A graphical representation of utility- and overall performance indicators, as well as current
tap water quality- and current overall tap water quality indicators is given in Figure 3.1.
This figure shows that in every aspect of utility performance and tap water quality
indicators, the situation in the nonproblematic group of utilities is better than the one in the
problematic group. The significant differences observed between real values of the overall
performance indicators for the nonproblematic and problematic group (75 and 59,
respectively) and, particularly, between the current overall tap water indicator values (68
and 36, respectively) come in support of the last assertion. Figure 3.2 confirms the
hypothesis that better performance corresponds to better consumer’s tap water quality.
Indeed, in Figure 3.2, the current (i.e., 2001) microbiological tap water quality varies in
direct proportion to the utility performance indicator. This finds also good support in Figure
3.3, although the Pearson Determination Coefficient (adjusted R2 = 0.27) does not, at first
sight, seem to confirm it. Indeed, it is easily understandable that the R2 be not high, since
the number of observations (i.e., statistical cases; n = 10) is very limited. A careful
examination of Figure 3.3 permits to notice that, on the whole, the current tap water quality
indicator is better with higher utility performance indicator.
3.3.2.3. Sensitivity analysis of the performance indicators The determination of variable weights (e.i., wi) showed in Table 3.4 and Table 3.5 was
based on two approaches. The first one consisted in taking into consideration of all
variables that exhibited a relatively good level of significance (at least at the 10% level,
P<0.1) in previous stages of the study, that is, in Chapters 1 and 2. The more significant the
variable proved to be, the bigger was its weight. The second approach entailed
consideration of all potential explanatory factors that have not yet been considered in the
ten utilities. These factors have been conferred weights based on literature indications (that
guided the author’s judgment). The fact of considering certain variables for indicator
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Figure 3.1. Relationships between utility performance indicators and current tap water quality indicators in nonproblematic (NP) utilities with those in problematic (P) utilities
Figure 3.2. Relationship between utility performance indicator and current (2001) microbiological tap water quality
101
Figure 3.3. Graphical representation of the relationship between the utility performance indicator (upi) and the current tap water quality indicator (twi)
development because they turned out to be statistically significant in previous stages of the
study involved an a priori stance. That is the reason why variables have been fixed
conferred weights before indicators were subjected to a sensibility analysis.
Two approaches of sensitivity analyses are being proposed for the utility performance
indicator: 1) making sub-indicator weights to vary; 2) excluding (i.e., withdrawing) sub-
indicators.
3.3.2.3.1. Variation of sub-indicator weights Varying utility performance sub-indicator weights (through doubling or halving of their
constitutive individual variable original weights) yielded eight scenarios (see Appendix H,
Table H.1). In fact, that operation represented much more than simply doubling or halving
original variable weights: it often implied simultaneous adjustment of some or all other
variable weights to maintain the sum of all weights equal to 1. When one sub-indicator
102
weight is doubled, the weight of at least one of the remaining three sub-indicators is
reduced. This weight reduction is mainly executed at the expense of the most weighted sub-
indicator among the other three, which often fell on the disinfection-related sub-indicator.
This process narrowed the gap between sub-indicator weights. Note that doubling the latter
sub-indicator’s weight resulted in cancelling all others’ weight since that sub-indicator
represented more than half of the overall weight. Likewise, when one sub-indicator weight
is halved, the weight of at least one of the remaining three is raised. The rise fell mainly on
the least weighted sub-indicators, which were the agricultural land use sub-indicator and
the raw water quality sub-indicator. This process also tended to diminish the gap between
sub-indicator weights. So, eventually, these weight changes had the effect of giving more
impact to sub-indicators (or variables) that did not have much of it in the original scenario.
The impact of sub-indicator weight variations is visible (see Appendix H, Table H.2).
However, in all of the eight scenarios, the nonproblematic group of utilities showed a
higher overall performance indicator. Moreover, in most cases, the gap between the overall
performance indicator values of the nonproblematic and problematic utility groups
remained very comparable to the one obtained in the original scenario (that is 75 (B) vs 59
(C), respectively; so the original gap is about 15 performance points). In fact, in seven of
the eight concerned scenarios, the gap varies between 10 and 20 performance points, with
the only one remaining being about 8 points in favour of the nonproblematic group.
Overall, the nonproblematic group of utilities had exclusively good performances, whereas
the problematic group reached such level of performance only three times out of eight.
3.3.2.3.2. Exclusion of sub-indicators One-at-a-time cancellation of utility performance sub-indicators yielded four scenarios (see
Appendix H, Table H.1). Except for one case (when the disinfection-related sub-indicator
was cancelled, resulting in ten individual variables with equal weights), the same approach
of raising the least sub-indicator weights while reducing the biggest ones (as described
above) was applied, and with the same tendency of narrowing the gap between the
remaining sub-indicator weights.
103
The impact of sub-indicator cancellations is obvious. As an example, conferring an
identical weight (that is 0.1) to all other individual variables except the ones composing the
disinfection-related sub-indicator resulted in a very comparable overall performance
indicator (the closest of all) between the nonproblematic and the problematic groups of
utilities (78 and 75, respectively) (Appendix H, Table H.2). However, in all other three
scenarios, the gap between the two utility groups (in terms of performance points) varies
between 10 and 20 as was the case above. Anew, on an overall basis, the nonproblematic
group of utilities exhibited exclusively good performances in these last four scenarios,
whereas the problematic group scored as much only on two occasions out of four.
3.3.3. Human and organizational factors Because of the particular nature of this information, human and organizational aspects were
treated as a case study (see Appendix E). According to Huberman and Miles (1994), a
case is a phenomenon of some sort occurring in a bounded context—in fact, the unit of
analysis. Two cases are being analyzed in a comparative style. The first case is represented
by a group of four nonproblematic utilities; the second—by a group of six problematic
utilities (see Figure 3.4). But these two cases may not be monolithic blocks; within each
case, there may be certain differences between member utilities. And these differences may
appear interesting enough to necessitate a brief analysis herein. Hence, the analytic
strategies that will be followed are within-case comparisons (between utilities in each
group as for managers’ socioprofessional characteristics and organizational factors) and
across-case comparisons (between the two groups of utilities (i.e., cases) according to the
same variables or distinctive features). To allow for within-case analyses, clusters have
been identified whenever possible. In the first case (i.e., nonproblematic or case-1), only
cluster A could be identified, whereas two clusters (B and C) were identified in the second
case (i.e., problematic or case-2) (see Figure 3.4). The criteria for identifying the clusters
are as follows. For case-1, cluster A is constituted of utilities that recorded no more than
one coliform episode during the considered three-year period. In case-2, cluster B is formed
of utilities that recorded from two to four episodes (in fact, utilities I and VIII recorded
exactly two episodes each), and cluster C—of utilities that recorded five or more episodes
104
during the studied three-year period.
Case-1 (nonproblematic utilities) Case-2 (problematic utilities) Level of being nonproblematic or problematic
≤ 1 episode A few episodes (2 to 4
episodes)
Many episodes
(≥ 5 episodes)
≤ 1 episode A few episodes (2 to 4
episodes)
Many episodes (≥ 5 episodes)
Highly
A
Utility II Utility III Utility V
Utility VII
C
Utility IV Utility VI Utility IX Utility X
Moderately
B
Utility I
Utility VIII
Figure 3.4. Clustering of the studied utilities according to the level of their being nonproblematic or problematic
The first step of qualitative comparative analyses will be done between clusters identified
within case-2. Hopefully, these analyses will allow for identifying certain interesting
distinctive features between case-2 member utilities.
3.3.3.1. Within-case analyses Since only one cluster has been identified in case-1 (i.e., cluster A), no cluster comparison
could be made for that case. As for the two case-2 clusters (i.e., B and C), three important
differences have been noticed between them: the two cluster B managers were the only
ones to have had some educational background dealing with the water issue. They have got
the lesser problematic utilities among the problematic group. The same cluster B managers
were those who most unequivocally welcomed supplementary training to come with 2001
105
QDWR implementation. Surprisingly, cluster C managers, with the most problematic
utilities of all, appeared to enjoy better support from local municipal authorities than cluster
B managers.
For the first point mentioned as a difference (i.e., educational background), there is no
doubt that utility managers who have got certificates (or diplomas) in civil engineering or
water sanitation were better prepared for the job, and were much more likely to be effective
and get good results (i.e., distributed water quality records) than those who have come to
learn directly on the job (see Appendix E). The level of being problematic for the two
compared clusters supports this. The second difference is rather evocative of the managers’
mental predisposition, with those supposedly best prepared for the job being also the ones
that were most willing to get better. The third point may have something to do with the
accuracy of cluster C managers’ responses, since, usually (as it will be demonstrated by
across-case analyses), the more problematic a small municipal utility is, the weaker is the
support its manager gets from local authorities.
3.3.3.2. Across-case analyses As mentioned earlier, the goal of across-case analyses is to identify and interpret significant
differences between case-1 and case-2 utilities, i.e., between nonproblematic and
problematic utilities. First of all, case-1 utility managers were older: 3 out of the 4 case-1
managers were aged (i.e., more than 50 years old), with mean age equalling 42 years,
whereas 4 out of the 6 case-2 managers were of mature years (i.e., 30 to 50 years old), with
mean age equalling about 38 years. It is important to note that none of the ten municipal
utility managers was very young (i.e., of age less than 30 years). Because, generally
speaking, experience comes with age, it is understandable to presume that case-1 managers
were also more experienced in the field of drinking water. Indeed, 3 out of the 4 case-1
managers were experienced or better, whereas 4 out of the 6 case-2 managers were little
experienced or lesser. This of course is an interesting indication, considering the historical
water quality indicators of the two groups of utilities. So, it appeared that the utilities with
106
the best historical water quality record were also those with the most experienced
managers. That is logical, but certainly not necessarily compulsory.
A relatively surprising finding was that none of the case-1 managers indicated to participate
in conferences or seminars, whereas one third of case-2 managers mentioned to take part in
such events. But this fact might not be so decisive: first, only 2 out of the 6 case-2
managers claimed to do so and, second, the number of those conferences and/or seminars
and their participants’ academic or training level might also mean a lot. Another somewhat
surprising finding is that only half of case-1 managers clearly claimed to have a good
knowledge of the 2001 QDWR about six months after their publication, whereas 5 out of
the 6 case-2 managers claimed good knowledge of new DWR at the same period. A
possible explanation of this seemingly laxness from apparently good managers might be
simply that “publication” did not mean immediate implementation, since the mentioned
standards had to come into effect only one year after their publication date.
And, again, half of case-1 managers were in favour of new DWR training requirements,
whereas 5 out of the 6 case-2 utilities were favourably disposed towards them. A possible
explanation of that is that case-1 managers did not see the necessity of such requirements
because of their utilities’ good historical water quality record. Moreover, half of case-1
managers considered their level of training already adequate (with regard to new DWR
implementation) versus only one third (2 out of 6) of case-2 managers; this might also be
an explaining factor.
Judging by the answers given by utility managers, case-2 utilities might appear much closer
to being ready for full compliance with new DWR than case-1 ones. However, taking into
account the whole situation of the concerned utilities, case-2 managers are rather suspected
of underestimating the immensity of challenges their respective utilities faced with regard
to new provincial standards. Conversely, case-1 managers’ relative reserve could indicate
their being really aware of the difficulty of tasks that fall on them due to new DWR, as well
as their concern about being able to take up such challenges. This would probably explain
why only 1 out of the 4 case-1 managers had clearly claimed an overall good appreciation
of 2001 QDWR, whereas 4 out of the 6 case-2 managers claimed satisfaction or better.
107
The higher degree of case-1 managers’ awareness of challenges facing them was confirmed
by the great relevance of issues that they mentioned as positive: half of them mentioned big
issues like strengthened bacteriological control and training needs for managers. None of
case-2 managers mentioned these factors. Instead, case-2 managers rather complained
about a supposedly excessive number of samples required by virtue of new DWR, and the
all-known financial needs. So, overall, case-1 managers’ preoccupations were much closer
to a better consumer’s tap water quality than were case-2 ones’.
The municipal authorities’ support was certainly not the least factor. All case-1 managers
stated receiving satisfactory or better support from local officials. As for case-2 utilities,
only half could claim satisfactory support. This could be a tremendous difference,
especially considering that these utilities had no other funding possibility than the one
coming through local authorities, whether that be municipal, provincial or federal money.
Finally, it is regretful to notice that across-case analyses could not be applied to the fact of
the utility manager's having educational background dealing with the water issue. In fact,
none of case-1 managers had such a background; as a result, no comparison could be made
between the two cases as for that distinctive feature. It could be reasonably presumed
however that if the concerned information were available in case-1, the comparison would
have confirmed observations made in within-case analyses (i.e., between case-2 utilities)
concerning that feature.
To conclude, across-case analyses led to the following clear distinctive features: 1) case-1
managers were older, but much more experienced; 2) case-1 managers appeared to be more
aware of challenges brought in by new 2001 QDWR and, hence, better prepared to face
them; and, 3) case-1 utilities appeared to receive significantly more support from their local
authorities than case-2 ones when it came down to the drinking water utility needs.
108
3.4. Conclusions Distribution system operational, infrastructure, and maintenance variables analyzed herein
showed some interesting trends in terms of distinctive features between the nonproblematic
and problematic groups of utilities in relation to their distributed water quality. The trends
noticed in the general portrait features have been almost systematically confirmed by
relating indicators.
Almost all indicators point towards better performances in nonproblematic utilities, which
are also those having the best current water quality in the distribution system. While, on the
whole all indicators are better in the nonproblematic group, a specific focus comes on
disinfection-related performance sub-indicators, and those for infrastructure and its
maintenance. It appears that these factors are really those that have the biggest impact on
distributed water quality in small utilities at study.
The sensitivity analyses applied to the utility performance indicator showed that the
methodology employed stands the test of individual variable and sub-indicator (or variable
group) weight changes. As a matter of fact, in the twelve scenarios tested, the
nonproblematic group of utilities exhibited exclusively good performances, whereas the
problematic group matched that only on some occasions (in 5 out of 12 scenarios), with
overall performance numeric values systematically lower than those of the nonproblematic
group of utilities.
The developed small utility performance indicators suggest that it is very difficult to make
good tap water from bad source water; however, it is very feasible to improve water quality
between the source and the consumer’s tap when adequate operational, infrastructure, and
maintenance, as well as human and organizational resources are brought together.
Qualitative studies in the field of drinking water are rare. This study gives indications that
human and organizational factors probably play a much more important role in the quality
of the consumer’s tap water than most stakeholders notice. It is obvious that even the most
sophisticated and complete equipment will not bring satisfaction in terms of distributed
109
water quality over a long span if not handled by a sufficiently qualified staff, supported by
an adequate organizational structure.
The comparative analyses accomplished in this study as for their managers’
socioprofessional characteristics and their organizational factors allowed identifying a
number of distinctive features, some of which appeared really worth attention. Within-case
analyses permitted to point out distinctive features between clusters of utilities pertaining to
case-2 (nonproblematic group). Three interesting distinctive features emerged within case-2
when clusters B and C managers were compared: 1) educational background dealing with
the water issue; 2) supplementary training issues relating to new QDWR; and 3) support
from local authorities. As for across-case analyses, they allowed highlighting such
important distinctive features as experience, awareness of and preparedness to face new
challenges brought in by 2001 QDWR, and all-around support from local authorities, all of
which heavily favoured case-1 utilities.
The findings of this study may be helpful for small utility managers, by allowing more
perceptiveness in their daily operational practices and favouring a better understanding and
awareness of their role and place in protecting public health through drinking water supply.
The findings may also be helpful for municipal officials and government bodies in terms of
personnel recruitment and (or) training policy making, and also in terms of better
understanding and assessing of the small utilities’ specific infrastructure needs and
subsequent allocation of appropriate resources.
To end, it has been identified a number of bias sources that could have affected this study’s
findings as well as their interpretations. Among the potential biases, the most important are
probably tied to little size of study sample (only ten utilities), and to manager interviews:
what they say is not necessarily what they really know, which is a common problem in
qualitative studies involving attitudes, behaviour and opinions. Nonetheless, it is reasonable
to think that the argumentations developed in this paper could be useful for those interested
in a better understanding of small utilities’ specificities and ways to make them serve, on a
constant basis, drinking water of irreproachable quality and in sufficient quantity.
110
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General conclusions and recommendations This research has documented many important characteristics of small Quebec drinking
water utilities. As it shows through all of chapters of the present thesis, small utilities are
not a monolithic world; instead, they may differ significantly according to number of
specificities dealing with their diverse structural components.
The first chapter allowed distinguishing three groups of utilities as for historically
distributed water quality: first, utilities which never experienced problems with
microbiological water quality during the period of reference; second, utilities that
occasionally encountered difficulties complying with drinking water regulations relating to
total coliforms; and, third, utilities which very often infringed upon quality standards. The
first two groups can be considered as distributing relatively safe water to their customers;
they have been called nonproblematic utilities. The last group obviously consists of utilities
that have major problems; thus, called problematic utilities.
From the portrait of small Quebec municipal utilities, emerged that most of problematic
utilities are indeed among those that directly chlorinate surface waters without any other
treatment. The new, 2001 QDWR made even bigger the challenges such utilities face; the
reason being that, unable to comply with coliform standards, these utilities will now have to
cope with parasites, viruses, and monitoring of trihalomethanes, to name a few. It is hard to
believe that small problematic utilities will overcome such obstacles, without managing, at
least in a filtration facility, to reduce NOM content in their distributed water.
It is to be strongly underlined, however, that, in terms of strict public health concern, the
problematic utilities are not necessarily serving water bearing more of a health threat than
the water served by the nonproblematic ones. In fact, the distinction into nonproblematic
and problematic has been made exclusively based on total coliform data, which may tell
more about the overall healthiness of the distribution system than about real health hazards.
As a matter of fact, none of databases used for this study included data on parasites like
Giardia lamblia and Cryptosporidium parvum, or on viruses or other waterborne pathogens
because of an almost total lack of data about them.
113
Studying the spatial and temporal variation of drinking water quality in the ten small
utilities allowed demonstrating in reality that problematic utilities have lower overall
microbiological water quality from the plant to the distribution extremity. However, raw
water quality appeared slightly favouring problematic utilities. So, all of these facts suggest
that the causes of observed differences between nonproblematic and problematic utilities
should be primarily searched for within the distribution system.
The most significant differences between the nonproblematic and the problematic group of
utilities were found in residual chlorine concentrations, starting at the chlorination facility
outlet and ending at distribution system extremity. Overall, disinfection-related water
quality parameters (i.e., chlorine doses and residuals) invariably favoured nonproblematic
utilities. Taking into account that all of the ten example small utilities (i.e., those studied in
Chapters 2 and 3) apply no other treatment than chlorination, this fact appears as the most
important in terms of potential explaining factor of differences observed between the two
utility groups as for historical water quality. Given the characteristics of the raw waters
used by the ten investigated utilities, the nonproblematic utilities appear to be able to
successfully deal with the challenge of efficient and simultaneous control of the acute
disease risk (represented by pathogenic micro-organisms) and the chronic health hazard
linked to DBPs, even though their THM levels were higher than those measured in
problematic utilities (with differences being not statistically significant). Nevertheless,
nonproblematic utilities should devote more attention to appropriate, balanced disinfection
practices, avoiding continually overestimating the microbial risk. As for problematic
utilities, the disinfection-related variables appeared being those upon which their managers
should primarily act to achieve relatively quick and substantial changes in terms of
distributed water quality. Problematic utilities need also a better control of natural organic
matter related parameters (i.e., TOC and UV254 nm). Among microbiological water quality
parameters in current distributed water quality, the most significant differences are related
to HPC bacteria counts. This fact points towards a better overall salubriousness within
water distribution lines pertaining to nonproblematic utilities.
114
Eight of the ten example small utilities obtain raw water halfway between surface and
groundwater, i.e., from surface wells. So, they do not fall directly into the category for
which filtration has been made mandatory by the 2001 QDWR. A recent visit (June 2003)
permitted to notice that all of the eight will most probably remain on the same type of raw
water. Nonetheless, they will have to demonstrate to the QME that they possess the
technical and operational capabilities to produce water that consistently meets the new
provincial standards without filtration. As an example, utility IV managers already
installed a UV-disinfection system to meet Giardia and Cryptosporidium requirements,
which they would have had very little chance to achieve with chlorination alone. It is
possible, even probable, that most of the seven others will follow in that direction. As for
the two unequivocally surface water utilities (i.e., those that drew their raw water from
lakes), they will undoubtedly have to install filtration or change water source for
groundwater. In fact, a recent visit permitted to notice that utility I is preparing to change
source for groundwater, whereas utility II is seriously engaged in a filtration facility
construction project.
The last chapter results underline the imperious need of optimization of operations and
infrastructures. Indeed, reviewing and comparing distribution operations and components
between nonproblematic and problematic utilities allowed noticing serious inaccuracies in
operations or techniques (e.g., manual chlorination) and shortages in a number of normal
distribution component parts (almost general absence of emergency chlorinators). That
being said, the indicators of performance for small utilities, developed using utility
operational, as well as infrastructure and maintenance characteristics, unequivocally point
towards better performances in nonproblematic utilities, which are also those having the
best current water quality in the distribution system, as a group. Special focus should come
on disinfection-related performance sub-indicators, and those for infrastructure and its
maintenance. It appears that these factors are really those that have the biggest impact on
distributed water quality in small utilities at study. Moreover, the developed small utility
performance indicators suggest that it is very difficult to make good tap water from bad
source water; however, it is very feasible to improve water quality between the source and
115
the consumer’s tap when adequate operational, infrastructure, and maintenance, as well as
human and organizational resources are brought together.
As far as human and organizational factors are concerned, indications are that they
probably play a much more important role in the quality of the consumer’s tap water than
most stakeholders notice. That is not surprising, since even the most sophisticated and
complete equipment will not bring satisfaction in terms of distributed water quality over a
long span if not handled by a sufficiently qualified staff, supported by an adequate
organizational structure. As a matter of fact, some of the analyzed utility manager
distinctive features appeared really worth attention. These related essentially to educational
background as it concerns the drinking water domain, and training issues tied to new
QDWR, experience in the drinking water field, awareness of and preparedness for the
challenges brought in by new QDWR, not to mention the all-important support from local
municipal authorities.
On the whole, the results of this research suggest that small utilities experience a serious
shortage of qualified managers. Even with the limited technical and financial resources they
have, these utilities would have achieved much better water quality standards if they were
managed by people having undergone an adequate preparation for the drinking water
industry. It is the responsibility of all levels of government (federal, provincial, municipal
or local) to ensure that this situation is corrected as soon as possible, since it represents a
big and direct threat to public health. The unfortunate incident that took place in May 2000
in the small community of Walkerton (Ontario, Canada) was mainly due to human error,
and that certainly was not an isolated case.
Small utilities are not attractive for the private sector, since their customer base is often too
narrow to allow for economies of scale. They are not rich enough to purchase new,
expensive technologies and equipments. Even when, under exceptional circumstances (e.g.,
2001 QDWR mandatory upgrading for most of provincial small utilities), they find
themselves with up-to-date drinking water facilities, they are not even well-off enough to
ensure keeping up with the times. Therefore, the public sector must bear the whole
responsibility and burden of small utilities to give them a chance to become and stay
116
efficient in terms of distributed water quality over the long term. Small utilities should not
be expected to take up such a challenge by their own.
The results of this study underline the necessity to promote integrated water resources
management, from the watershed to the consumer’s tap. This requires joint governmentally
centralized management programs integrating agriculture/animal husbandry, as well as
forestry and environmental sections. The agriculture/animal husbandry section would be in
charge of agricultural land use factors (initiating measures to limit water resources
pollution tied to agricultural production and animal faeces). The forestry section would be
responsible for controlling deforestation and its corollaries, such as erosion strengthening
(erosion being considered an important contributing factor of turbidity of raw surface
waters). As for the environmental section, it would be in charge of limiting water resources
pollution directly tied to human beings and activities (sewage, leisure activities, industrial
productions, and so forth). Only specialized governmental institutions could undertake and
implement that type of joint management programs, but there is no getting away from that
if water resources are to appropriately serve the present population of the Planet, while
being adequately preserved for the future generations. These considerations are valid for
developed and developing countries alike.
Finally, it appears necessary to mention some limitations of this study. For instance, the
different data sources utilized in Chapter 1 led to different data considerations that may
render difficult a comparison of the results obtained herein to those of other studies. In
Chapter 3, the little size of study sample (only ten utilities) and the manager interviews
(who do not necessarily say all that they think or know) are probably potential sources of
bias. Future studies on small Quebec drinking water utilities may be advantaged by taking
much more important study samples (i.e., numbers of utilities) than those mentioned in this
work. As an example, surveying the whole population of small Quebec municipal utilities
(n=927) in Chapter 1, in lieu of the 250 actually surveyed, would certainly have given
much more representativeness to the results of this study. Likewise, taking all 114 Chapter
1 responding utilities for further study in Chapters 2 and 3, would also have significantly
strengthened the conclusions of the research. In Chapter 2, adding viruses and parasites to
117
studied current distributed water microbiological parameters would have made the study
almost complete in terms of microbial contaminants of public health relevance.
Unfortunately, all of these possibilities could not be exploited in the present study, due to
limitations in time, as well as financial, technical, and logistic means.
APPENDICES
Appendix A
Questionnaire of the survey on drinking water quality management practices in small Quebec utilities (survey has been conducted in French)
Groupe de Recherche sur l’Eau Potable de l’Université Laval – GREPUL –
ENQUÊTE SUR LES PRATIQUES DE GESTION DE LA QUALITÉ DE L’EAU POTABLE
SECTION I : IDENTIFICATION 1. Nom de la municipalité ___________________________________________________ 2. Population totale de la municipalité ____________________ 3. Adresse de la municipalité _________________________________________________ _________________________________________________________________________ 4. Numéro de téléphone ____________________________ 5. Numéro de télécopie _____________________________ 6. Adresse de courrier électronique (si disponible) de la municipalité __________________ 7. Nom, fonction et numéro de téléphone du répondant _____________________________ _________________________________________________________________________ 8. Date de remplissage du questionnaire _________________
120
SECTION II : INFORMATIONS GÉNÉRALES
9. a) Êtes-vous desservis en eau potable par une autre municipalité ?
Oui Non b) Si oui, veuillez nous retourner ce questionnaire sans répondre à aucune autre question 10. Desservez-vous une autre municipalité ? oui Non 11. Combien de personnes dessert votre système d’approvisionnement en eau potable ? ___________ 12. Quelle est votre source d’approvisionnement en eau potable ? (Veuillez indiquer le nom de la source)
Lac ________________________ Rivière _________________________ Puits
Autre (veuillez spécifier) _________________________________________________________ 13. a) Disposez-vous uniquement d’un poste de chloration ? Oui Non b) Si non, quel type de traitement de l'eau appliquez-vous ? (Veuillez en préciser les différentes étapes) ________________________________________________________________________ ______________________________________________________________________________________________________________________________________________________________ 14. a) Avez-vous effectué une modification de votre chaîne de traitement après 1990 ?
Oui Non b) Si oui, quand ? __________________ , et quelles ont été les modifications apportées ? _______________________________________________________________________________ ______________________________________________________________________________________________________________________________________________________________
SECTION III : CARACTÉRISTIQUES DE L’EAU BRUTE 15. Veuillez indiquer la valeur des paramètres nommés ci-après pour votre eau brute : Hiver 1 (moyenne saisonnière) pH _______ Carbone organique total ___________ Turbidité ___________ Couleur vraie ____________ Température _________ Coliformes totaux ___________ Été 2 (moyenne saisonnière) pH _______ Carbone organique total ___________ Turbidité ___________ Couleur vraie ____________ Température _________ Coliformes totaux ___________
1 Octobre à mars 2 Avril à septembre
121
SECTION IV : PRATIQUES DE DÉSINFECTION 16. Quel type de désinfectant utilisez-vous ?
Chlore gazeux (Cl2) Hypochlorite de sodium (NaClO) Chloramines Autre (veuillez préciser) ____________________________________________
17. a) Disposez-vous d’un bassin de contact pour le désinfectant ?
Oui Non b) Si oui, quelle en est la capacité ? _____________________ c) Ce bassin est-il muni de chicanes ? (les schémas figurant ci-dessous servent d’exemples)
Oui Non
d) Pourriez-vous fournir une approximation du temps de séjour de l’eau dans le bassin de contact ? ______________________ 18. a) Disposez-vous d’un ou plusieurs réservoirs d’eau traitée à l’usine ?
Oui Non b) Si oui, combien sont-ils ? 1 2 3 c) Quelle est la capacité de chaque réservoir ? 1er ______________ 2ème ______________ 3ème _______________ d) Les réservoirs mentionnés comportent-ils des chicanes ? Oui Non 19. Au cas où vous n’auriez ni réservoir ni bassin de contact, de quelle façon procédez-vous au mélange du chlore avec l’eau ? ______________________________________________________ _______________________________________________________________________________ 20. Quelle est la dose moyenne de désinfectant apportée ? Hiver ___________ Été __________
SECTION V : EAU TRAITÉE (AVANT DISTRIBUTION) 21. Quel est le débit moyen de l’eau à l’entrée du réseau ? __________________ 22. Veuillez indiquer la valeur des paramètres cités ci-dessous pour l’eau traitée, après désinfection (à l’entrée du réseau) Hiver
Schéma 1 Schéma 2
EntréeEntrée
SortieSort ie
122
pH _____ Carbone organique total ______________ Turbidité _____________ Couleur vraie ______________ Coliformes totaux ____________ (nombre d'échantillons positifs) Chlore résiduel libre ______________ Trihalométhanes totaux ________________ Été pH _____ Carbone organique total ______________ Turbidité _____________ Couleur vraie ______________ Coliformes totaux ____________ (nombre d'échantillons positifs) Chlore résiduel libre ______________ Trihalométhanes totaux _________________
SECTION VI : RÉSEAU DE DISTRIBUTION
Paramètres de qualité de l’eau à l’extrémité du réseau de distribution 23. Veuillez indiquer la valeur des paramètres suivants pour l’eau, à l’extrémité du réseau de distribution Hiver pH _____ Carbone organique total ______________ Turbidité _____________ Couleur vraie _________ Coliformes totaux __________ (nombre d'échantillons positifs) Chlore résiduel libre ______________ Trihalométhanes totaux ________________ Été pH _____ Carbone organique total ______________ Turbidité _____________ Couleur vraie __________ Coliformes totaux _________ (nombre d'échantillons positifs) Chlore résiduel libre ______________ Trihalométhanes totaux ________________
Caractéristiques générales de l’infrastructure du réseau 24. Quelle est la longueur totale approximative des conduites de votre réseau ? __________ 25. Quel est l’âge approximatif de votre réseau ? _______ ans 26. Pourriez-vous nous fournir une indication (en ordre de grandeur approximatif) du pourcentage de conduites revenant à chaque type de matériau ? Fonte ________ % PVC _______ % Autres ________________________________ % 27. Auriez-vous une idée du nombre moyen de bris de conduites par année ? ___________
Pratiques d’entretien du réseau de distribution 28. a) Procédez-vous à des rinçages de votre réseau ? Oui Non b) Si oui, combien de fois par an ? ___________ , et à quelle période de l’année ?
Hiver Printemps Été Automne 29. a) Connaissez-vous des problèmes de corrosion dans votre réseau ?
Oui Non b) Dans l’affirmative, avez-vous instauré des mesures de lutte contre la corrosion des conduites dans le réseau ? Oui Non
123
c) Si oui, veuillez indiquer lesquelles ______________________________________________ ______________________________________________________________________________________________________________________________________________________________
Pratiques de gestion de la qualité de l’eau dans le réseau 30. Auriez-vous une idée du temps de séjour de l'eau à l'extrémité du réseau ? ________________ 31. a) Procédez-vous à la rechloration au sein du réseau ? Oui Non b) Si oui, de combien de postes de rechloration disposez-vous ? ________ c) Où se situent-ils ?
À proximité de l’usine En mi-réseau Aux extrémités du réseau 32. Combien d’échantillons prélevez-vous annuellement dans le cadre du suivi de la qualité microbiologique de l’eau dans le réseau ? ____________________________ 33. Combien en prélevez-vous d’avril à septembre ? ___________________ 34. À combien estimeriez-vous le pourcentage d’échantillons pris aux extrémités du réseau ? __________ %
SECTION VII : CONTRAINTES DIVERSES RECENSÉES 35. À votre avis, quelles sont les contraintes de gestion de la qualité de l’eau auxquelles vous faites face présentement ? _______________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ 36. Au cas où vous auriez eu des échantillons positifs de coliformes au cours des dernières années, quelles en ont été selon vous les causes (origines) ? _________________________ __________________________________________________________________________________________________________________________________________________
MERCI DE VOTRE AIMABLE COLLABORATION !
Appendix B
Table B.1. Atypical bacteria data generated by the studied utilities from 1997 through 1999
Number of positive samples
Percentage of total number of samples
Average colony counts, cfu/100 mL*
1997 1998 1999 1997 1998 1999 1997 1998 1999
Percentiles Percentiles Percentiles
Min C10 C50 C90 Max Mean Min C10 C50 C90 Max Mean Min C10 C50 C90 Max Mean
Nonproblematic utilities
15 11 3** 7.3 5.8 1.6** 1 1 2 200 200 2 1 1 15 200 200 6 3 3 35** 56 56 31**
Problematic utilities
23 63 48
11.9 20.6 11.7 1 1 13 200 200 12 1 1 10 200 200 26 1 1 6 165 200 24
* The determination limit was indicated by the QME accredited laboratories as > 200 cfu/100 mL; so this value has been considered herein as the maximum. ** Data obviously not representative because of too small sample size (n=3).
125
Table B.2. Distribution water boiling notices issued by the studied utilities from 1996 through 2001
Number of notices
1996 1997 1998 1999 2000 2001 Six-year period
Single utility
Total Annual average
Single utility
Total Annual average
Single utility
Total Annual average
Single utility
Total Annual average
Single utility
Total Annual average
Single utility
Total Annual average
Six-year total
Six-year average
II. 0 0 1 0 0 1
III. 1 0 0 0 1 1
V. 0 1 0 0 1 0
Nonproblematic utilities
VII. 0
1 0.25
0
1 0.25
0
1 0.25
0
0 0
0
2 0.5
0
2 0.50 7 0.29
I. 0 1 1 2 1 0
IV. 0 0 2 1 0 0
VI. 1 1 5 3 0 0
VIII. 0 0 1 0 4 0
IX. 0 2 4 2 2 2
Problematic utilities
X. 0
1 0.16
0
4 0.66
0
13 2.17
2
10 1.67
0
7 1.17
1
3 0.50 38 1.05
Appendix C
Data gathered on spatial and temporal variation of drinking water quality in ten small Quebec municipal utilities (data presented in French) NOTES: “Systèmes” stands for drinking water utilities “Statut” denotes utilities’ water quality status (i.e., being problematic or nonproblematic) “Brute” denotes raw water “Chlorée” designates chlorinated water (i.e., sampled at facility, just after chlorination) “Poste” designates chlorination facility “Centre” indicates water sampled in the central part of distribution system “Extremité” indicates water sampled at distribution system extremity
127
Systèmes Statut Date Mois Brute Chlorée Extremité Brute ChloréeI P 07-mai 5 3 3 3 6,33 6,45I P 08-août 8 17,1 16,7 17,2 6,57 6,61I P 04-juin 6 10,5 10,3 9,8 7,61 7,73I P 11-juil 7 15,6 10,2 15 7,18 7,29I P 30-oct 10 8,2 8,1 12,8 6,94 7,02II NP 03-juil 7 20,1 14,5 11,5 7,89 8,16II NP 30-juil 7 22,2 16,1 13,3 7,28 7,6II NP 07-juin 6 16,3 11,2 8,2 7,79 8,12II NP 29-oct 10 8,9 11,4 12,2 7,01 7,21II NP 15-mai 5 7,2 8,4 6,5 6,24 7,68III NP 08-mai 5 6 6,2 7 8,3 8,2III NP 05-juin 6 6,6 6,8 7,5 8,02 8,23III NP 31-juil 7 8 8,2 15 7,83 7,55III NP 04-juil 7 7,3 7,5 13,6 8,29 8,09III NP 29-oct 10 8,7 8,7 13,3 7,02 7,25IV P 10-juil 7 7,9 9 12,2 7,78 7,9IV P 07-août 8 7,8 9 14,4 7,4 7,58IV P 22-mai 5 8,7 9,1 7 7,85 7,53IV P 13-juin 6 8,4 9,3 9,8 7,78 8,02IV P 31-oct 10 9,1 9,1 10,9 7,74 7,77V NP 06-juin 6 7,5 8,4 9,2 7,29 7,06V NP 31-oct 10 7 10 12 6,71 6,77V NP 09-mai 5 7 7,7 7,1 6,78 6,75V NP 05-juil 7 11,2 10,3 12 6,92 7,61V NP 01-août 8 9,7 9,4 14,2 6,33 6,36VI P 23-mai 5 6,6 6,9 6,5 7,6 7,5VI P 09-juil 7 6,4 5,8 8,6 10,38 10,4VI P 06-août 8 6,5 6 9,4 6,53 6,51VI P 18-juin 6 7 6,6 7,5 7,64 7,53VI P 31-oct 10 6,6 6,7 8,5 7,37 7,35VII NP 24-mai 5 6,7 7,2 9,6 8,07 7,82VII NP 19-juin 6 7 8,9 12,5 8,11 7,93VII NP 18-juil 7 7 9,5 16,1 7,95 7,7VII NP 14-août 8 6,9 9,6 18 7,63 7,85VII NP 31-oct 10 8 9 14 7,82 7,89VIII P 20-juin 6 9,3 8,7 10,5 6,85 7,01VIII P 16-juil 7 7,9 8,8 9,5 6,28 6,3VIII P 15-août 8 8 10,5 15,5 6,36 6,4VIII P 25-mai 5 8 8,5 10,5 6,84 6,89VIII P 29-oct 10 7,7 8 10 6,64 6,72IX P 14-mai 5 6,9 8 6,2 7,72 7,26IX P 13-août 8 8,8 9,8 14,2 7,17 6,9IX P 11-juin 6 7,5 8,4 8,7 7,45 7,5IX P 17-juil 7 8,7 9,6 13,2 7,64 7,23IX P 30-oct 10 13,1 9 12,5 7,13 6,96X P 06-juil 7 8,9 9,3 12,6 7,89 7,79X P 30-oct 10 11,5 12 12 7,46 7,57X P 18-mai 5 6,2 6,6 6 7,76 7,97X P 12-juin 6 7,4 9,1 10,1 7,75 7,93X P 02-août 8 9,3 11,4 14,8 7,29 7,31
Température, oC pH
Table C.1. Water quality data gathered in result of the 2001 sampling campaign in ten small Quebec municipal utilities
128
Systèmes Statut Date Mois Brute Chlorée Extrémité Brute Chlorée ExtrémitéI P 07-mai 5 0,42 0,34 0,36 3,25 3,18 3,18I P 08-août 8 1,51 1,34 1,31 3,94 3,95 3,8I P 04-juin 6 0,81 0,55 0,56 6,67 6,95 6,42I P 11-juil 7 1,7 0,82 0,75 3,5 3,45 3,26I P 30-oct 10 0,87 1,05 1,25 3,44 3,58 3,34II NP 03-juil 7 1,26 1,03 0,83 2,53 2,71 2,68II NP 30-juil 7 1,02 0,88 0,91 2,68 2,82 2,8II NP 07-juin 6 1,1 1,1 0,86 5,14 5,55 5,47II NP 29-oct 10 1,66 1,2 0,84 2,9 3,11 2,66II NP 15-mai 5 1,24 1,22 1,29 2,76 2,9 2,83III NP 08-mai 5 0,19 0,15 0,12 0,95 0,95 0,97III NP 05-juin 6 0,4 0,27 0,2 2,23 2,61 1,67III NP 31-juil 7 0,3 0,2 0,16 1,01 0,96 0,96III NP 04-juil 7 0,24 0,31 0,16 1,5 1,24 1,11III NP 29-oct 10 0,19 0,23 0,19 1,11 1,3 1IV P 10-juil 7 0,24 0,72 0,75 0,43 0,45 0,53IV P 07-août 8 0,62 0,72 0,78 0,41 0,34 0,45IV P 22-mai 5 0,29 0,35 1,2 0,84 0,43 0,4IV P 13-juin 6 1,02 0,37 0,49 0,92 1,02 1,16IV P 31-oct 10 0,33 0,51 0,5 0,37 0,56 0,39V NP 06-juin 6 2,15 2,4 0,15 1,07 1,3 1,06V NP 31-oct 10 0,2 0,32 0,38 0,3 0,41 0,66V NP 09-mai 5 0,11 0,15 0,14 0,42 0,37 0,35V NP 05-juil 7 0,09 0,19 0,14 0,42 0,42 0,46V NP 01-août 8 0,15 0,12 3,93 0,44 0,38 0,91VI P 23-mai 5 0,43 0,35 0,36 0,23 0,21 0,24VI P 09-juil 7 0,28 0,21 0,4 0,33 0,36 0,32VI P 06-août 8 0,57 0,3 0,22 0,26 0,25 0,27VI P 18-juin 6 1,03 0,45 0,17 0,29 0,37 0,22VI P 31-oct 10 0,42 0,27 0,39 0,34 0,43 0,43VII NP 24-mai 5 0,33 0,61 0,57 2,34 1,96 1,9VII NP 19-juin 6 0,22 0,47 0,35 2,61 2,17 2,32VII NP 18-juil 7 0,16 0,43 0,31 1,55 4,62 1,58VII NP 14-août 8 0,21 0,96 0,64 2,28 1,75 2,26VII NP 31-oct 10 0,18 0,75 6,36 3,76 2,41 2,03VIII P 20-juin 6 0,1 0,08 0,08 0,81 0,82 0,91VIII P 16-juil 7 0,1 0,06 0,09 0,57 2,56 0,57VIII P 15-août 8 0,32 0,41 0,14 0,98 0,8 0,85VIII P 25-mai 5 0,15 0,12 0,07 1,11 0,83 0,82VIII P 29-oct 10 0,24 0,11 0,14 0,73 0,74 0,74IX P 14-mai 5 0,21 0,34 0,36 0,55 0,71 1,72IX P 13-août 8 0,08 0,34 0,57 0,37 0,44 0,73IX P 11-juin 6 0,28 0,42 0,32 0,93 1,18 1,1IX P 17-juil 7 0,58 0,32 0,36 2,1 4,57 2,1IX P 30-oct 10 0,14 0,33 0,27 0,3 0,53 0,56X P 06-juil 7 0,1 0,08 0,13 1,46 1,4 1,37X P 30-oct 10 0,32 0,89 0,26 1,74 1,6 1,58X P 18-mai 5 0,06 0,08 0,09 1,36 1,24 1,22X P 12-juin 6 0,08 0,08 0,07 2,67 2,61 2,79X P 02-août 8 0,14 0,21 0,22 1,67 1,49 1,43
Turbidité, utn COT, mg/l
Table C.1. Water quality data gathered in result of the 2001 sampling campaign in ten small Quebec municipal utilities (Continued-1)
129
Systèmes Statut Date Mois Brute Chlorée Extrémité Brute Chlorée Centre ExtrémitéI P 07-mai 5 0,11 0,08 0,1 22 0 0 0I P 08-août 8 0,148 0,112 0,111 23 0 0 0I P 04-juin 6 0,15 0,121 0,121 31 0 0 0I P 11-juil 7 0,138 0,108 0,091 116 1 0 0I P 30-oct 10 0,122 0,09 0,098 13 0 0 1II NP 03-juil 7 0,092 0,07 0,066 11 0 0 0II NP 30-juil 7 0,082 0,06 0,059 0 0 0 0II NP 07-juin 6 0,133 0,108 0,099 91 0 0 0II NP 29-oct 10 0,109 0,09 0,081 28 0 0 0II NP 15-mai 5 0,07 0,047 0,047 9 0 0 0III NP 08-mai 5 0,006 0,012 0,008 4 0 0 0III NP 05-juin 6 0,047 0,039 0,035 42 0 0 0III NP 31-juil 7 0,02 0,016 0,018 0 0 0 0III NP 04-juil 7 0,025 0,022 0,023 2 0 0 0III NP 29-oct 10 0,036 0,032 0,037 6 0 0 0IV P 10-juil 7 0,013 0,018 0,019 28 0 0 0IV P 07-août 8 0,022 0,018 0,02 24 4 2 0IV P 22-mai 5 0,007 0,013 0,023 7 0 0 0IV P 13-juin 6 0,039 0,051 0,049 23 0 0 0IV P 31-oct 10 0,009 0,01 0,013 2 0 0 0V NP 06-juin 6 0,05 0,06 0,037 34 0 0 0V NP 31-oct 10 0,005 0,005 0,002 108 0 0 0V NP 09-mai 5 0,008 0,002 0,002 8 0 0 0V NP 05-juil 7 0,007 0,008 0,008 0 0 0 0V NP 01-août 8 0,008 0,007 0,023 0 0 0 0VI P 23-mai 5 0,001 0,001 0,006 2 0 0 0VI P 09-juil 7 0,007 0,007 0,007 0 0 0 0VI P 06-août 8 0 0,001 0,002 0 0 0 0VI P 18-juin 6 0,027 0,025 0,022 5 0 0 0VI P 31-oct 10 0,006 0,008 0,004 0 0 0 0VII NP 24-mai 5 0,07 0,054 0,056 4 0 1 0VII NP 19-juin 6 0,103 0,088 0,096 1 0 0 0VII NP 18-juil 7 0,081 0,06 0,065 0 0 0 0VII NP 14-août 8 0,069 0,05 0,061 2 0 0 0VII NP 31-oct 10 0,085 0,058 0,07 4 0 0 0VIII P 20-juin 6 0,035 0,038 0,037 23 0 0 0VIII P 16-juil 7 0,02 0,021 0,029 26 0 0 0VIII P 15-août 8 0,018 0,018 0,019 35 0 0 0VIII P 25-mai 5 0,016 0,017 0,016 8 0 0 0VIII P 29-oct 10 0,032 0,032 0,032 4 0 0 0IX P 14-mai 5 0,031 0,024 0,019 18 0 0 0IX P 13-août 8 0,006 0,014 0,033 0 4 4 0IX P 11-juin 6 0,037 0,042 0,048 0 0 0 0IX P 17-juil 7 0,006 0,02 0,021 0 0 0 0IX P 30-oct 10 0,007 0,003 0,012 2 0 0 0X P 06-juil 7 0,022 0,019 0,027 0 0 0 0X P 30-oct 10 0,019 0,022 0,081 8 0 0 0X P 18-mai 5 0,009 0,015 0,009 10 0 0 0X P 12-juin 6 0,047 0,046 0,054 0 0 0 0X P 02-août 8 0,023 0,021 0,029 3 0 0 0
UV254 nm Bactéries coliformes totales, ufc/100 ml
Table C.1. Water quality data gathered in result of the 2001 sampling campaign in ten small Quebec municipal utilities (Continued-2)
130
Systèmes Statut Date Mois Brute Chlorée Centre Extrémité Brute Chlorée Centre ExtrémitéI P 07-mai 5 2040 20 50 40 400 40 3 0I P 08-août 8 2210 10 40 263 400 25 30 64I P 04-juin 6 457 10 536 216 134 0 0 11I P 11-juil 7 480 3 10 30 66 6 6 0I P 30-oct 10 70 6 3 10 195 2 3 1II NP 03-juil 7 2990 20 60 170 400 0 0 0II NP 30-juil 7 4500 10 150 60 400 1 1 1II NP 07-juin 6 60 0 0 0 349 1 0 0II NP 29-oct 10 60 3 3 10 400 3 4 3II NP 15-mai 5 106 3 6 30 93 0 0 0III NP 08-mai 5 690 20 100 30 203 42 0 0III NP 05-juin 6 170 10 40 60 400 0 0 3III NP 31-juil 7 2160 36 230 280 0 0 0 0III NP 04-juil 7 50 20 30 20 29 5 13 6III NP 29-oct 10 120 13 36 20 172 0 0 14IV P 10-juil 7 4140 126 130 160 400 18 23 24IV P 07-août 8 3800 90 53 33 41 51 29 6IV P 22-mai 5 2880 30 90 90 15 0 7 0IV P 13-juin 6 190 0 0 3 43 16 0 0IV P 31-oct 10 50 0 3 0 54 2 2 0V NP 06-juin 6 1740 30 10 20 400 5 0 0V NP 31-oct 10 130 10 3 6 223 0 0 0V NP 09-mai 5 220 20 60 70 306 0 0 0V NP 05-juil 7 100 13 30 56 3 0 0 0V NP 01-août 8 440 10 13 20 0 1 0 0VI P 23-mai 5 2206 20 100 560 7 0 0 0VI P 09-juil 7 630 10 20 23 4 2 0 0VI P 06-août 8 1340 0 23 20 120 0 0 0VI P 18-juin 6 93 70 3 33 5 400 0 0VI P 31-oct 10 160 0 10 16 0 0 0 0VII NP 24-mai 5 300 7 23 50 0 0 0 0VII NP 19-juin 6 0 0 40 42 6 1 0 0VII NP 18-juil 7 146 23 53 76 1 0 0 0VII NP 14-août 8 80 0 16 20 24 0 0 0VII NP 31-oct 10 0 0 20 0 28 0 2 0VIII P 20-juin 6 70 26 33 60 69 0 0 0VIII P 16-juil 7 113 30 45 43 176 0 0 0VIII P 15-août 8 100 10 20 40 179 1 0 0VIII P 25-mai 5 367 70 100 57 16 0 0 0VIII P 29-oct 10 123 23 0 13 14 0 0 0IX P 14-mai 5 2000 60 260 1080 400 54 69 90IX P 13-août 8 1090 20 50 150 0 18 11 1IX P 11-juin 6 140 80 20 23 0 0 0 0IX P 17-juil 7 90 66 86 53 0 0 0 0IX P 30-oct 10 40 0 13 16 18 0 0 6X P 06-juil 7 520 0 470 240 202 1 127 181X P 30-oct 10 643 0 13 36 400 0 12 3X P 18-mai 5 70 0 30 30 33 0 0 0X P 12-juin 6 290 16 20 23 12 7 1 0X P 02-août 8 135 25 46 66 78 0 0 0
BHAA, ufc/ml Bactéries atypiques, ufc/100 ml
Table C.1. Water quality data gathered in result of the 2001 sampling campaign in ten small Quebec municipal utilities (Continued-3)
131
Dose_de_chlore, mg/lSystèmes Statut Date Mois Poste Poste Centre ExtrémitéI P 07-mai 5 2,12 0,59 0,04 0I P 08-août 8 3,06 0,52 0,03 0,05I P 04-juin 6 2,11 1,26 0,01 0I P 11-juil 7 3,47 0,09 0,01 0,03I P 30-oct 10 3,71 0,93 0,01 0,01II NP 03-juil 7 7,04 1,5 1,19 0,55II NP 30-juil 7 5,63 0,69 0,35 0,51II NP 07-juin 6 5,63 2,2 0,78 1,26II NP 29-oct 10 7,04 1,85 0,13 0,46II NP 15-mai 5 5,63 1,47 1,35 0,44III NP 08-mai 5 1,42 0,39 0,07 0,04III NP 05-juin 6 1,32 0,51 0,23 0,07III NP 31-juil 7 1,28 0,14 0,08 0,14III NP 04-juil 7 1,37 0,02 0,01 0,02III NP 29-oct 10 1,98 1,24 0,66 0,8IV P 10-juil 7 3,39 0,02 0 0IV P 07-août 8 2,54 0 0,03 0IV P 22-mai 5 4,24 0,43 0,27 0,16IV P 13-juin 6 3,39 2,2 2,2 2,2IV P 31-oct 10 3,39 0,38 0,07 0,11V NP 06-juin 6 0,49 0,25 0,42 0,38V NP 31-oct 10 0,7 0,4 0,18 0,17V NP 09-mai 5 0,47 0,96 0,59 0,31V NP 05-juil 7 0,62 0,63 0,42 0,35V NP 01-août 8 0,51 0,63 0,29 0,24VI P 23-mai 5 1,3 0,12 0,03 0,04VI P 09-juil 7 1,5 0,34 0,25 0,16VI P 06-août 8 1,2 0,4 0,19 0,07VI P 18-juin 6 1,2 0,17 0,13 0,11VI P 31-oct 10 1,3 1,18 0,17 0,08VII NP 24-mai 5 3,19 0,19 0,11 0,03VII NP 19-juin 6 1,53 0,13 0,04 0,02VII NP 18-juil 7 2,15 0,12 0,04 0,03VII NP 14-août 8 2,79 0,33 0,01 0,01VII NP 31-oct 10 1,79 0,12 0,09 0,12VIII P 20-juin 6 1,55 0,14 0,02 0,03VIII P 16-juil 7 2,88 0,1 0,08 0,12VIII P 15-août 8 3,17 0,1 0,08 0,11VIII P 25-mai 5 1,84 0,08 0,04 0,07VIII P 29-oct 10 2,07 0,05 0 0IX P 14-mai 5 2,02 0,47 0,03 0,01IX P 13-août 8 2,42 0,03 0,05 0IX P 11-juin 6 1,73 0,59 0,52 0,01IX P 17-juil 7 2,45 0,06 0,04 0IX P 30-oct 10 2,33 0,4 0,38 0X P 06-juil 7 1,02 0,03 0 0X P 30-oct 10 1,19 0,5 0,07 0,02X P 18-mai 5 0,62 0,09 0,02 0,18X P 12-juin 6 0,42 0,01 0 0X P 02-août 8 2,13 0,32 0 0
Chlore_résiduel_libre, mg/l
Table C.1. Water quality data gathered in result of the 2001 sampling campaign in ten small Quebec municipal utilities (Continued-4)
132
Systèmes Statut Date Mois Poste Centre ExtrémitéI P 07-mai 5 20,9 9,77 23,67I P 08-août 8 22,44 28,14 31,51I P 04-juin 6 44,05 67,89 57,04I P 11-juil 7 16,86 51,67 56,5I P 30-oct 10 45,95 67,94 44,44II NP 03-juil 7 50,33 70,03 74,66II NP 30-juil 7 41,71 56,63 39,6II NP 07-juin 6 20,15 38,83 57,5II NP 29-oct 10 17,28 60,58 50,92II NP 15-mai 5 50,77 37,59 59,86III NP 08-mai 5 15,79 13,31 11,81III NP 05-juin 6 9,21 9,53 14,14III NP 31-juil 7 4,47 5,1 12,05III NP 04-juil 7 2,32 3,34 13,78III NP 29-oct 10 13,59 18,31 17,11IV P 10-juil 7 0 0,72 0IV P 07-août 8 0 0 0IV P 22-mai 5 5,52 5,18 4,19IV P 13-juin 6 7,11 8,42 8,43IV P 31-oct 10 7,8 7,73 8,66V NP 06-juin 6 6,17 5,67 6,77V NP 31-oct 10 6,8 10,21 9,04V NP 09-mai 5 4,63 8,96 7,66V NP 05-juil 7 1,51 1,85 4,41V NP 01-août 8 0 1,28 1,89VI P 23-mai 5 0,9 2,08 3,8VI P 09-juil 7 0 1,82 0VI P 06-août 8 0,15 1,32 2,19VI P 18-juin 6 11,03 6,06 10,2VI P 31-oct 10 7,28 7,23 0,48VII NP 24-mai 5 4,49 12,2 9,98VII NP 19-juin 6 13,28 15,45 12,22VII NP 18-juil 7 8,08 5,61 8,23VII NP 14-août 8 7,1 7,8 6,71VII NP 31-oct 10 10,14 32,35 27,88VIII P 20-juin 6 8,21 9,66 14,95VIII P 16-juil 7 0,23 1,58 6,7VIII P 15-août 8 2,27 0,72 1,65VIII P 25-mai 5 5,2 5 4,82VIII P 29-oct 10 0 8,74 4,65IX P 14-mai 5 3,86 1,52 17,39IX P 13-août 8 1,61 0 1,16IX P 11-juin 6 4,36 8,18 5,18IX P 17-juil 7 2,89 7,91 2,63IX P 30-oct 10 11,07 11,36 15,21X P 06-juil 7 0,59 0,95 0,83X P 30-oct 10 7,86 25 19,12X P 18-mai 5 4,08 5,01 7,23X P 12-juin 6 5,38 3,09 7,77X P 02-août 8 7,26 1 5,67
THM_totaux, ug/l
Table C.1. Water quality data gathered in result of the 2001 sampling campaign in ten small Quebec municipal utilities (Continued-5)
Appendix D
Questionnaire of the survey on utility operation, infrastructure, and maintenance, as well as human and organizational factors in the ten studied small Quebec municipal utilities (survey has been conducted in French)
ENQUÊTE TECHNIQUE ET SOCIOLOGIQUE I. ENQUÊTE TECHNIQUE SECTION 1 : IDENTIFICATION DU RÉPONDANT 1. Nom de la municipalité _____________________________________________________ 2. Nom et fonction du répondant __________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 3. Date de remplissage du questionnaire __________________________________________ SECTION 2 : INFORMATIONS GÉNÉRALES SUR LES COMPOSANTES DU SYSTÈME DE DISTRIBUTION 4. Âge du réseau de distribution __________________________________________________ 5. En dehors de la chloration, faites-vous un autre traitement ou ajustement (filtration, ajout de chaux, de polyphosphates, autre) ? _________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 6. Disposez-vous d’un chlorateur d’urgence ? Avez-vous eu à en faire usage (lors de défaillances avérées du système principal de désinfection) ? ______________________________________
134
_____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 7. Quel type de désinfectant avez-vous utilisé au cours des cinq dernières années ? _________ _____________________________________________________________________________ 8. Procédez-vous à une injection du chlore en continu ? De quel type de chlorateur disposez-vous ? Où est situé le chlorateur ? Disposez-vous d’un bassin ou d’un réservoir de contact? Veuillez en fournir les caractéristiques (dimensions, rainures ou chicanes internes, temps de séjour de l’eau). Où s’effectue habituellement la mesure de la dose administrée et du chlore résiduel libre ? Selon quelle périodicité ? Intégrez-vous le facteur C x T dans vos critères de désinfection ? Que représente-t-il pour vous ? ____________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 9. Avez-vous des réservoirs de stockage dans le système ? À quel endroit? Quelle en est la capacité ? Quel est le temps moyen de séjour de l’eau dans ce(s) réservoir(s) ? ____________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________
135
10. Quelle est l’importance relative des divers types de conduites et la profondeur de leur enfouissement ? ______________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 11. La longueur, la configuration de votre réseau ou l’état de vos conduites rendent-ils nécessaires l’érection de postes de rechloration ? En disposez-vous ? Si oui, à quel niveau ? Comment percevez-vous l’impact de la longueur sur la qualité ? _________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 12. La corrosion des conduites métalliques est-elle un problème dans votre réseau ? Quelles en sont les manifestations concrètes et quelles sont les mesures éventuelles prises pour sinon l’endiguer du moins l’atténuer ? Comment percevez-vous l’impact de la corrosion sur la qualité? _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 13. Les rinçages du réseau sont-elles une pratique courante au niveau de votre système ? Quelle en est la périodicité ? Quelles en sont les raisons et/ou circonstances ? Comment percevez-vous l’impact des rinçages sur la qualité ? _______________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________
136
_____________________________________________________________________________ 14. Enregistrez-vous fréquemment des bris de conduite dans votre réseau ? Quelle en serait la fréquence moyenne ? Combien de temps vous faut-il en général pour y trouver solution ? Qu’en est-il des fuites (pourcentage des pertes d’eau qui y seraient liées) ? _____________________ _____________________________________________________________________________ _____________________________________________________________________________ II. ENQUÊTE SOCIOLOGIQUE SECTION 3 : INFORMATIONS GÉNÉRALES SUR LE GESTIONNAIRE / OPÉRATEUR 15. Depuis combien de temps exercez-vous dans le domaine ?___________________________ Corollaire : jeune (< 30 ans)______ d’âge mûr (30-50 ans) ______ âgé (> 50 ans)_____ 16. Qualification professionnelle (diplôme, formation accélérée, apprentissage sur le tas, autre) _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 17. Réseau d’experts auquel il a accès (sources d’informations techniques : revues, publications diverses régulièrement consultées ; contacts socioprofessionnels, etc.) ____________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ SECTION 4 : RENSEIGNEMENTS SUR LA GESTION DU SYSTÈME DE DISTRIBUTION 18. Êtes-vous seulement chargé de gérer le système de distribution d’eau potable ? Si non, quelles autres activités menez-vous et quelle proportion de votre temps y consacrez-vous ? _____________________________________________________________________________ _____________________________________________________________________________
137
_____________________________________________________________________________ _____________________________________________________________________________ 19. Avez-vous un adjoint ou suppléant ? Si oui, quelle formation ce dernier a-t-il suivi (école professionnelle, stages pratiques, apprentissage sur le tas, etc.) ___________________________ _____________________________________________________________________________ _____________________________________________________________________________ 20. Avez-vous pris connaissance du nouveau règlement ? Que pensez-vous des dispositions y figurant concernant la formation des gestionnaires et/ou opérateurs ? ____________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 21. Estimez-vous votre formation adéquate pour l’atteinte des objectifs mis en avant dans le cadre du règlement ? Qu’en est-il de votre adjoint ou suppléant éventuel ? __________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 22. Comment percevez-vous votre système de distribution du point de vue fiabilité et performance des équipements, des infrastructures ? Êtes-vous satisfait de son état présent ou pensez-vous que des améliorations y sont nécessaires voire indispensables ? _______________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 23. Ces améliorations, qui répondraient de toute évidence à des besoins clairement exprimés et correspondant à des contraintes de gestion bien identifiées, porteraient-elles sur les équipements, les infrastructures, les ressources humaines ? _____________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________
138
24. Les dispositions préconisées par le nouveau règlement permettront-elles à votre avis de lever les contraintes de gestion relevées ci-dessus ? En clair, ce règlement rendra-t-il votre système plus gérable ? En quoi ? _________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 25. Vous croyez-vous techniquement, financièrement et humainement prêt à appliquer immédiatement toutes les dispositions du nouveau règlement ? Si non, quel serait à vos yeux le délai raisonnable pour pouvoir vous y conformer entièrement ? ___________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 26. De façon générale, le nouveau règlement a-t-il répondu à vos attentes, vos aspirations ? Quels en sont à vos yeux les dispositions pertinentes et les points qui mériteraient d’être revus ? _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ 27. La question de l’approvisionnement de la population en eau potable est-elle une préoccupation majeure des élus municipaux ? Vous sentez-vous soutenu dans vos démarches, requêtes, activités
139
visant à assurer la desserte d’une eau qui soit toujours de la meilleure qualité ?______________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________
Appendix E
Table E.1. Socioprofessional characteristics and opinions of nonproblematic utility managers
Variables or distinctive features Utility II Utility III Utility V Utility VII
Age Aged Of mature years Aged Aged
Experience Little experienced Experienced Very experienced Experienced
Training background in the field of drinking water
Learning on the job, and a three-day training course
Learning on the job Learning on the job, and a few training sessions
Learning on the job
Percentage of overall work time devoted to drinking water utility management
20 percent 25 percent 30 percent 25 to 30 percent
Level of knowledge of new (2001) QDWR Good knowledge Good knowledge No knowledge Partial knowledge
Other duties
Road works; sewer; building Director of Public Works: roads, sewer, etc.
Sewer; public works Sewer; road works
141
Table E.1. Socioprofessional characteristics and opinions of nonproblematic utility managers (continued-1)
Variables or distinctive features Utility II Utility III Utility V Utility VII
Opinion of 2001 QDWR training requirements
Training requirements pertinent Supplementary training necessary No specific opinion Training requirements pertinent, but a little too complex
Training adequacy for 2001 QDWR Training not adequate; needed to catch up Training adequate, but needed improvements concerning regulatory follow-up
Training sufficient as things stood (a year from retirement)
Training not adequate; planned to catch up
Satisfaction with infrastructure and equipments performance and reliability
Satisfied Satisfied Total satisfaction Satisfied
Utility management aspects in which 2001 QDWR brought improvements
Water supply safety Water quality monitoring (control) Not acquainted enough with new DWR to express an opinion
General knowledge of drinking water issues in rise thanks to new DWR
Utility readiness for full compliance with 2001 QDWR
Not 100 percent ready to apply new DWR; cf. the above-mentioned details
Not totally ready Not acquainted with new DWR Not totally ready; especially financially
142
Table E.1. Socioprofessional characteristics and opinions of nonproblematic utility managers (continued-2)
Variables or distinctive features Utility II Utility III Utility V Utility VII
Probable period of time needed to achieve full compliance with 2001 QDWR
Needed more than a year to be 100 percent ready to comply with new DWR
Needed a few months to fully comply No idea; not acquainted with new DWR
Needed 1 through 3 years to be able to fully comply
General opinion of 2001 QDWR Generally speaking, had a good appreciation of the new DWR
No specific opinion No knowledge of new DWR Making involved parties aware of their responsibilities and accountable for them
Specifically noticed 2001 QDWR positive and negative points
Not able to make a judgment New DWR positive point(s): strengthening of total coliform bacteria testing in small utilities
No knowledge of 2001 DWR New DWR positive point(s): making training compulsory for all water utility managers
143
Table E.2. Organizational factor specificities in nonproblematic utilities
Variables or distinctive features Utility II Utility III Utility V Utility VII
Networking specificities QME publications; socioprofessional contacts: consulting engineers; peers
Contacts with consulting engineer firms
Socioprofessional contacts Socioprofessional contacts: Quebec Water Technicians Association; peers
Year-long assistant availability Assistant available (responsible for half of work time allotted to utility management)
No assistant No assistant No assistant
Temporary substitute availability No substitute Substitute available Substitute available Substitute available
Way assistant and/or substitute learned job Assistant learned on the job Substitute learned on the job Substitute learned on the job Substitute learned on the job
Assistant’s/substitute’s training adequacy for 2001 QDWR
Assistant will need even more training to meet new requirements
Substitute will need further training Substitute will need further training
Substitute’s training is inadequate; needs to catch up
Infrastructure and equipments reliability
Infrastructure and equipments reliable Infrastructure and equipments reliable Infrastructure and equipments reliable and efficient
Infrastructure and equipments reliable
144
Table E.2. Organizational factor specificities in nonproblematic utilities (continued)
Variables or distinctive features Utility II Utility III Utility V Utility VII
Necessity of improvements to infrastructure and equipments in view of 2001 QDWR
Improvements necessary for infrastructure and equipments alike
Some improvements in infrastructure and equipments may be desirable
Improvements needed but not in infrastructure and equipments
Improvements necessary for infrastructure and equipments alike
Kind of improvements needed or expected Big improvements expected in equipments; some infrastructure changes to come; managing staff: from part time to full time
Improvements: infrastructure and equipments
Improvements: urgently in need of staff
Improvements: equipments, staff
Prioritization of the drinking water issue by local authorities
Drinking water is a major concern for local authorities
Drinking water issues are a priority for local officials, mayor in particular
Drinking water is an important issue for elected representatives
Elected representatives more open-minded about drinking water issues than before
Level of support displayed by local authorities
All possible municipal support offered to utility managers
Vigorous municipal support to water utility managers
Support from local authorities satisfactory (positive attitude)
Rising support from local officials with new DWR
145
Table E.3. Socioprofessional characteristics and opinions of problematic utility managers
Variables or distinctive features Utility I Utility IV Utility VI Utility VIII Utility IX Utility X
Age Of mature years Of mature years Of mature years Of mature years Aged Aged
Experience Very little experienced Little experienced Very experienced Very little experienced Experienced Very little experienced
Training background in the field of drinking water
General basic education in civil engineering, plus learning on the job
Learning on the job Learning on the job, general secondary education, and catch-up course in water quality
Complementary studies diploma in water sanitation
Learning on the job Learning on the job
Percentage of overall work time devoted to drinking water utility management
20 percent of work time devoted to the drinking water utility management
25 percent of work time devoted to utility management
25 percent of work time devoted to utility management
50 percent of work time devoted to utility management
10percent of work time devoted to utility management
33 percent of work time devoted to utility management
Level of knowledge of new (2001) QDWR
Good knowledge of 2001 QDWR
Good knowledge of 2001 QDWR
Good knowledge of 2001 QDWR
Good knowledge of 2001 QDWR
Good knowledge of 2001 QDWR
Partial knowledge of 2001 QDWR
146
Table E.3. Socioprofessional characteristics and opinions of problematic utility managers (continued-1)
Variables or distinctive features Utility I Utility IV Utility VI Utility VIII Utility IX Utility X
Other duties Other duties: town planning; road works; sewer; public works
Director of Public Works: road works, sewage, public works
Road works; snow clearance; public works
Sewer; wastewater treatment plant
Whole municipal administration
Road works; building
Opinion of 2001 QDWR training requirements
Supplementary training needed and welcomed to comply with 2001 QDWR
Training requirements pertinent, but will need time to be feasible
Training requirements pertinent
Training requirements pertinent; supplementary training welcomed
Training requirements pertinent
Training requirements acceptable if they do not demand too much time
Training adequacy for 2001 QDWR Principal manager’s training adequate
Principal manager’s training not yet adequate
Principal manager’s training adequate, but needs to catch up
Principal manager’s training not adequate; needs to catch up
Principal manager’s training not adequate; further training indispensable
Principal manager’s training not adequate; further training necessary
Satisfaction with infrastructure and equipments performance and reliability
Satisfied with infrastructure and equipments performance and reliability
Satisfied with infrastructure and equipments performance and reliability
Satisfied with infrastructure and equipments performance and reliability
Satisfied with infrastructure and equipments performance and reliability
Satisfied with infrastructure and equipments performance and reliability
Satisfied with infrastructure and equipments performance and reliability
147
Table E.3. Socioprofessional characteristics and opinions of problematic utility managers (continued-2)
Variables or distinctive features Utility I Utility IV Utility VI Utility VIII Utility IX Utility X
Utility management aspects in which 2001 QDWR brought improvements
Water supply system safer and better manageable because of undergone and upcoming improvements in relation to new DWR
Improvements in water quality control; however, much more time to devote to utility management
Improvements: better water quality control
Improvements: not big for equipments, but significant as for water supply sources (active search for alternative sources under way)
Improvements: most probably more manageable, since safer, water distribution system
Improvements: better utility management through better water quality control
Utility readiness for full compliance with 2001 QDWR
No; in search of technical assistance, financial support from provincial authorities, and of at least one substitute
No; in need of federal/provincial financial contribution
100 percent ready for compliance with 2001 QDWR
No; especially from a technical point of view
No; not straight away No; human resources available, but undergoing training
Probable period of time needed to achieve full compliance with 2001 QDWR
Could not indicate a deadline for full compliance with 2001 QDWR
Needed less than a year to fully comply with new DWR
Without delay
A year would be probably sufficient to fully comply
2 years needed to be able to fully comply
A year might appear too short of a time to fully comply
148
Table E.3. Socioprofessional characteristics and opinions of problematic utility managers (continued-3)
Variables or distinctive features Utility I Utility IV Utility VI Utility VIII Utility IX Utility X
General opinion of 2001 QDWR Generally speaking, 2001 QDWR are more difficult to comply with but reassuring from a safety standpoint
Generally speaking, satisfied with new DWR
No specific feeling New DWR came up to expectations as for regulatory control
Satisfied with water supply securitizing
No specific opinion
Specifically noticed 2001 QDWR positive and negative points
2001 QDWR positive point(s): satisfied with the new DWR in their entirety
2001 QDWR negative point(s): too high spending for small municipalities; required water sample numbers too high in relation to municipality size
2001 QDWR positive point(s): saw no negative point
2001 QDWR negative point(s): required water sample numbers might be excessive
2001 QDWR positive/negative point(s): Saw no weak point; may be funding
2001 QDWR negative point(s): a little too much rigor (severe measures)
149
Table E.4. Organizational factor specificities in problematic utilities
Variables or distinctive features Utility I Utility IV Utility VI Utility VIII Utility IX Utility X
Networking specificities Local journals; QME publications
QME publications; Quebec Municipalities Federation; socioprofessional contacts with QME agents
Journals; contacts with engineers, peers, Quebec Water Sanitation Society; accredited laboratories
“Réseau Environnement”; consulting engineer firms; accredited laboratories; meetings with peers at conferences, seminars, etc.
None Socioprofessional contacts: consulting engineer firms; participation to seminars
Year-long assistant availability No assistant No assistant Assistant available Assistant available No assistant No assistant
Temporary substitute availability Substitute available Substitute available Substitute available No substitute Substitute available Substitute available
Way assistant and/or substitute learned job Substitute learned on the job
Substitute learned on the job
Assistant and substitute learned on the job
Assistant learned on the job
Substitute learned on the job
Substitute learned on the job
Assistant’s/substitute’s training adequacy for 2001 QDWR
Substitute’s training inadequate
Substitute’s training inadequate
Both assistant and substitute will need further training
Assistant’s training insufficient; needs to catch up
Substitute’s training insufficient; further training indispensable
Substitute’s training insufficient; further training necessary
150
Table E.4. Organizational factor specificities in problematic utilities (continued-1)
Variables or distinctive features Utility I Utility IV Utility VI Utility VIII Utility IX Utility X
Infrastructure and equipments reliability Infrastructure and equipments reliable
Infrastructure and equipments reliable
Infrastructure and equipments reliable
Infrastructure and equipments performance acceptable
Infrastructure and equipments reliable
Infrastructure and equipments reliable
Necessity of improvements to infrastructure and equipments in view of 2001 QDWR
Improvements needed in infrastructure and equipments in view of 2001 QDWR
Improvements needed in chlorine dosage system: continuous readings, emergency system
Improvements needed in accordance with new DWR
Improvements needed in equipments, flushing methods, checking pumps, and the like
Improvements needed in relation to new DWR
Improvements needed in infrastructure and equipments
Kind of improvements needed or expected
Improvements needed in infrastructure, equipments, and staff
Improvements: equipments and staff
Improvements: equipments and staff training
Improvements: essentially equipments, then infrastructure and staff
Improvements desirable all along the line
Improvements desired: emergency chlorinator, colorimeter (fieldwork kit)
151
Table E.4. Organizational factor specificities in problematic utilities (continued-2)
Variables or distinctive features Utility I Utility IV Utility VI Utility VIII Utility IX Utility X
Prioritization of the drinking water issue by local authorities
Local officials not prioritizing drinking water issue to desired point
Drinking water is a major concern for local authorities
Local officials not always prioritizing drinking water issue
Drinking water is a major concern for local authorities
Drinking water is a major concern for local authorities
Drinking water is a major concern for local authorities
Level of support displayed by local authorities
Local support not always available: too much discussion and beating about the bush
Sufficient support: priority for local authorities and for citizens
Moderate support from local officials, especially for regulatory compliance
Some support, but not always with dispatch
All needed support from local authorities
Sufficient support from local officials
Appendix F
Table F.1. Distribution system infrastructure information for nonproblematic utilities
Characteristics Utility II Utility III Utility V Utility VII
Utility age, years 28 90 24 26
Storage tanks 1 2 2 2
Storage tanks capacity, m3 681 2 x 454 2 x 1702.5 2 x 567.5
Average storage time in tanks, h 24 24 72 48
Grey iron pipes, % 0 5 0 0
Ductile iron pipes, % 95 0 90 100
PVC pipes, % 5 90 10 0
Other material pipes, % 0 5 0 0
Infrastructure variables
Overall utility pipe length, km 12 10 17.6 3.8
Flushing periodicity, per year 2 2 1 2 Maintenance variables
Annual pipe breakage rate, breaks/100km/year 16 10 0 0
153
Table F.1. Distribution system infrastructure information for nonproblematic utilities (continued)
Characteristics Utility II Utility III Utility V Utility VII
Mode of chlorine injection According to flowrate According to flowrate According to flowrate According to flowrate
Usual residual chlorine checkpoint(s) Chlorination facility Chlorination facility Chlorination facility Chlorination facility Operational variables
Frequency of residual chlorine measurement Once a day Once a day Once a day Once a day
Storage tanks localization Middle of distribution system Chlorination facility Extremity of distribution system Chlorination facility
Emergency chlorinator Present Absent Absent Absent
Type of chlorinator Dosage pump Dosage pump Dosage pump Dosage pump Infrastructure variables
Localization of chlorinator Chlorination facility Chlorination facility Chlorination facility Chlorination facility
Distribution network flushing Not uncommon Not uncommon Not very common Not uncommon
Reasons for flushing As a preventive measure As a curative measure As a preventive measure As a preventive measure
Impact of flushing on water quality Positive impact Positive impact Positive impact Positive impact
Main break frequency Not very frequent Not very frequent No break so far No break so far
Maintenance variables
Distribution main leakage Negligible Negligible Not very significant Negligible
154
Table F.2. Distribution system infrastructure information for problematic utilities
Characteristics Utility I Utility IV Utility VI Utility VIII Utility IX Utility X
Utility age, years 61 23 26 41 54 21
Storage tanks 2 1 1 1 1 2
Storage tanks capacity, m3 2 x 681 363.2 1362 572 908 2 x 136.2
Average storage time in tanks, h 48 48 72 12 24 48
Grey iron pipes, % 20 0 0 40 10 0
Ductile iron pipes, % 40 0 80 60 50 10
PVC pipes, % 40 90 20 0 40 90
Other material pipes, % 0 10 0 0 0 0
Infrastructure variables
Overall utility pipe length, km 20 10 7.8 45 10 7.9
Flushing periodicity, per year 4 2 1 1 2 3 Maintenance variables
Annual pipe breakage rate, breaks/100km/year
25 10 38 0 10 0
155
Table F.2. Distribution system infrastructure information for problematic utilities (continued-1)
Characteristics Utility I Utility IV Utility VI Utility VIII Utility IX Utility X
Mode of chlorine injection Constant Constant According to flowrate Constant Manual According to flowrate
Usual residual chlorine checkpoint(s)
Chlorination facility Tank and extremity Chlorination facility Chlorination facility Storage tank Chlorination facility Operational variables
Frequency of residual chlorine measurement
Once in two days Once in two days Once in two days Once a day Once a day Once a day
Storage tanks localization Chlorination facility Chlorination facility Chlorination facility Midway between source and chlorination facility
Middle of distribution system
Source
Emergency chlorinator Present Absent Present Absent Absent Absent
Type of chlorinator Dosage pump Dosage pump Dosage pump Dosage pump Manual chlorination Dosage pump
Infrastructure variables
Localization of chlorinator
Chlorination facility Storage tank inlet Chlorination facility
Chlorination facility Manually into tank Source
156
Table F.2. Distribution system infrastructure information for problematic utilities (continued-2)
Characteristics Utility I Utility IV Utility VI Utility VIII Utility IX Utility X
Distribution network flushing
Common practice Not uncommon Not very common Not very common Not uncommon Common practice
Reasons for flushing As a curative measure As a curative measure As a curative measure As a curative measure As a curative measure As a curative measure
Impact of flushing on water quality
Positive impact Positive impact Positive impact Positive impact Positive impact Positive impact
Main break frequency Not very frequent Not very frequent Not very frequent No break so far Not very frequent No break so far
Maintenance variables
Distribution main leakage
Not very significant Not significant Negligible
Not significant Negligible Negligible
Appendix G
Table G.1. Explanations as to how the parameter values were converted into performance scores
Variables Performance points attribution details
Agricultural land use
The performance scores have been attributed based on the QME database classification mentioned in Table 2.1. For utilities located in municipalities with an annual phosphorus balance below zero (P2O5 < 0 kg/ha/year), that is, municipalities with extremely low agricultural pressure, the maximum score (e.i., 100 performance points) has been attributed. For utilities located in municipalities with P2O5 = 0 kg/ha/year, 50 performance points have been allotted. Utilities with slight phosphorus surplus, but less than the 20 kg/ha/year QME established threshold, received 25 points. And utilities located in municipalities in surplus situation (i.e., with P2O5 > 20 kg/ha/year or located in administratively designated as “surplus” municipalities) scored no performance points (i.e., 0 points) on that variable.
Raw water TOC
In the 2001 QDWR, a raw water TOC concentration of 3 mg/L was given as an indication for surface water utilities, for which filtration was not becoming compulsory. This value has been considered equalling the 50th percentile of performance points (i.e., C50 or median) on that variable. Based on that assumption, performance scores have been attributed to studied utilities as follows: 100 points for utilities with C1≤TOC≤C20, as average raw water TOC concentration (mg/L); 75 points to utilities with C20<TOC≤C40. Utilities with C40<TOC≤C60 received 50 points, and those averaging C60<TOC≤C80 received 25 points. C1, C20, C40, C60 and C80 equalled 0.06, 1.2, 2.4, 3.6, and 4.8 mg/L, respectively. None of the utilities exhibited average raw water TOC concentration exceeding the latter value.
Raw water turbidity
In the 2001 QDWR, a raw water turbidity threshold of 5 ntu was mentioned as a maximum for surface water utilities, for which filtration was not becoming compulsory. Thus, 5 ntu has been considered equalling the 100th percentile of performance points (i.e., C100 or maximum). Based on that consideration, performance scores have been allotted to utilities as follows: 100 points for utilities with C1≤turbidity≤C20, as average raw water turbidity (ntu); 75 points to utilities with C20<turbidity≤40. C1, C20, C40 equalled 0.05, 1, and 2 ntu, respectively. None of studied utilities had an average raw water turbidity exceeding 1.5 ntu.
158
Table G.1. Explanations as to how the parameter values were converted into performance scores (continued-1)
Variables Performance points attribution details
Raw water total coliforms
In the 2001 QDWR, a raw water total coliform count of 100 cfu/100 mL was given as an indication for surface water utilities, for which filtration was not becoming compulsory. This value has been considered equalling the 50th percentile of performance points on that variable. Thus, performance scores have been attributed to studied utilities as follows: 100 points for utilities with C1≤total coliform counts≤C20, as average raw water total coliform counts (cfu/mL); 75 points to utilities with C20<total coliform counts≤C40. C1, C20, C40 equalled 2, 40, and 80 cfu/100 mL, respectively. None of studied utilities had average raw water total coliform counts exceeding 41 cfu/100 mL.
Raw water HPC bacteria
The 2001 QDWR gave a maximum of 500 cfu/mL at distribution system extremity for HPC bacteria. Since not distributed but rather raw water is concerned herein, this threshold is used only as an indication, to allow for relative performance comparisons between studied utilities. Therefore, the 500 cfu/mL mark has been considered as equalling the C20 of performance points on that variable. Consequently, performance scores have been allotted as follows: 100 points to utilities with C1≤HPC bacteria counts≤C20; 75 points to utilities with C20<HPC bacteria counts≤C40; 50 points to those with C40<HPC bacteria counts≤C60; 25 points to utilities with C60<HPC bacteria counts≤C80; and 0 points to those with HPC bacteria counts>C80. C1, C20, C40, C60, and C80 equalled 25, 500, 1000, 1500, and 2000, respectively.
Raw water atypical bacteria
The 2001 QDWR gave a maximum of 200 cfu/100mL in the distribution system for atypical bacteria. Since not distributed but rather raw water is concerned herein, this threshold is used only as an indication for comparison purposes. Thus, the 200 cfu/100mL mark has been considered as equalling the C50 of performance points on that variable. Consequently, performance scores have been allotted as follows: 100 points to utilities with C1≤atypical bacteria counts≤C20; 75 points to utilities with C20< atypical bacteria counts≤C40; 50 points to those with C40< atypical bacteria counts≤C60; 25 points to utilities with C60< atypical bacteria counts≤C80; and 0 points to those with atypical bacteria counts>C80. C1, C20, C40, C60, and C80 equalled 4, 80, 160, 240, and 320, respectively.
159
Table G.1. Explanations as to how the parameter values were converted into performance scores (continued-2)
Variables Performance points attribution details
CT value
In the United States Environmental Protection Agency Guidance Manual entitled “Alternative Disinfectants and Oxidants” (USEPA, 1999), it was mentioned, “… 4-log virus inactivation is achievable with a CT of 15 to 60 mg⋅min/L for most temperatures. These values have been considered as equalling respectively C3 and C12 of performance points on that variable. ” Since all ten utilities being studied have chlorination as the only treatment applied, it appears reasonable to think that this is the objective they should pursue, taking into account the fact that the 3-log Giardia cyst inactivation and the 2-log Cryptosporidium oocyst inactivation (all of which are required for surface water utilities in 2001 QDWR) are beyond reach with chlorination alone. Hence, very conservatively, performance scores have been attributed as indicated herein: 100 points to utilities with CT≥C60 mg⋅min/L; 75 points to those with C30≤CT<C60; 50 points to utilities with C15≤CT<C30; 25 points to those with C5≤CT<C15; and 0 points to utilities with CT<C5. Note that C5, C15, C30, and C60 equalled 25, 75, 150, and 300, respectively.
Residual chlorine checking frequency This information was obtained from utility managers before 2001 QDWR’s full implementation (October, 2001). Seven out the ten studied utilities used to check for residual chlorine on a daily basis (see Appendix F). The three others used to measure residual chlorine only once in two days. Thus, on a relative performance basis, 100 points have been allotted to those applying daily residual chlorine measurement, while those doing such a measurement once in two days received 50 points.
Residual chlorine checkpoints appropriateness
Judging by indications given in 2001 QDWR, an adequate residual chlorine controlling through the whole distribution system requires having checkpoints (or sampling points) at least in two locations, that is, the chlorination facility outlet (or storage tank outlet, if this tank is located at facility after the point of chlorine injection) and the distribution system extremity or thereabouts. Nine utility managers declared using to check for residual chlorine only at the facility (with one at the storage tank outlet), while only one utility had residual chlorine sampling points at facility and nearby system extremities. The only utility that checked for residual chlorine at both facility and extremities scored 100 points on that variable; all other nine received 50 points.
160
Table G.1. Explanations as to how the parameter values were converted into performance scores (continued-3)
Variables Performance points attribution details
Utility age According to Fougères et al. (1998), the useful life of a drinking water distribution pipe can rarely go over one hundred years. So, this number has been taken as reference value, with C1 equalling 1 year and C100 being 100 years. Thus, utilities that had age≤C20 scored 100 points on that variable; 75 points for C20<age≤C40; 50 points for C40<age≤C60; 25 points for C60<age≤C80; and 0 points for utilities with age>C80 (i.e., 80 years).
Pipe material
Four types of pipe material have been identified in studied utilities (see Appendix F). According to Villeneuve et al. (1998), grey iron pipes are excessively corrodible, and are being abandoned for that reason. So no performance points had been allotted for grey iron percent of utility pipe material, nor for other pipe material percent (negligible). Only ductile iron and PVC pipe percents (i.e., the sum of the percents of these materials for each utility) have been converted into performance points. Since the possible maximum of pipe material percent is 100, this number has been taken as reference value. If the sum of ductile iron and PVC percents is =C60, the concerned utilities received 50 points; 75 points for C60<pipe material percent≤C80; and 100 points for pipe material percent >C80. No utility had percent less than C60 (that is, 60 %).
Pipe breakage
According to McDonald et al. 1997, a main break rate can be considered abnormally high when it exceeds 40/100km/year. None of studied utilities recorded as many breaks. However, that value has been taken as indication (as maximum or C100) for comparison purposes. If utility’s annual pipe breakage rate ≤C20, 100 points were allotted; 75 points for C20<pipe breakage rate≤C40; 50 points for C40<pipe breakage rate≤C60; 25 points for C60<pipe breakage rate≤C80; and 0 points for annual pipe breakage rate >C80. Note that C20, C40, C60, and C80 equalled 8, 16, 24, and 32breaks/100km/year, respectively.
System flushing
In the conditions of the province of Quebec (Canada), it is a sign of good management routine (or practice) to perform at least two flushings of the drinking water distribution network each year, with the first coming in early Spring (i.e., generally by April) and the second in late Autumn (by October). Many utilities perform more than two flushings per year. Thus, utilities that did only 1 flushing per year received performance 50 points on that variable; and 100 points for 2 flushings or more. All utilities did at least one flushing each year.
161
Table G.1. Explanations as to how the parameter values were converted into performance scores (continued-4)
Variables Performance points attribution details
Tap water residual chlorine
The maximum average residual chlorine concentration in any one of the studied distribution systems (i.e., utilities) was about 0.8 mg/L (see Appendix C). This value represents the average for water samples taken at three sampling points (that are, chlorination facility, central part of distribution system, and distribution system extremity). To allow for relative performance comparisons, the 0.8 mg/L value has been considered as equalling C100. Thus, for average tap water residual chlorine ≤C20, 0 points were allotted; 25 points for C20< tap water residual chlorine ≤C40; 50 points for C40< tap water residual chlorine ≤C60; 75 points for C60< tap water residual chlorine ≤C80; and 100 points for tap water residual chlorine >C80. Note that C20, C40, C60, and C80 equalled 0.16, 0.32, 0.48, and 0.64 mg/L, respectively.
Tap water HPC bacteria The maximum average HPC bacteria counts in any one of the studied distribution systems (i.e., utilities) was about 140 cfu/mL (see Appendix C). This value represents the average for water samples taken at three sampling points (that are, chlorination facility, central part of distribution system, and distribution system extremity). To allow for relative performance comparisons, that value has been considered as equalling C100 (note that the 2001 QDWR gave a threshold of 500 cfu/mL for HPC bacteria water samples to be taken at distribution system extremity). Thus, for average tap water HPC bacteria counts ≤C20, 100 points were allotted; 75 points for C20< tap water HPC bacteria counts ≤C40; 50 points for C40< tap water HPC bacteria counts ≤C60; 25 points for C60< tap water HPC bacteria counts ≤C80; and 0 points for average tap water HPC bacteria counts >C80. Note that C20, C40, C60, and C80 equalled 28, 56, 84, and 112 cfu/mL, respectively.
Tap water atypical bacteria The maximum average atypical bacteria counts in any one of the studied distribution systems (i.e., utilities) was about 30 cfu/100mL (see Appendix C). This value represents the average for water samples taken at three sampling points (that are, chlorination facility, central part of distribution system, and distribution system extremity). To allow for relative performance comparisons, that value has been considered as equalling C100 (note that the 2001 QDWR gave a threshold of 200 cfu/100mL for atypical bacteria in distributed water). Thus, for average tap water atypical bacteria counts ≤C20, 100 points were allotted; 75 points for C20< tap water atypical bacteria counts ≤C40; 50 points for C40< tap water atypical bacteria counts ≤C60; 25 points for C60< tap water atypical bacteria counts ≤C80; and 0 points for average tap water atypical bacteria counts >C80. Note that C20, C40, C60, and C80 equalled 6, 12, 18, and 24 cfu/100mL, respectively.
Appendix H
Table H.1. Sensitivity analysis of the utility performance indicator (weight variations)
Variation of utility performance sub-indicator weights Cancellation of respective sub-indicator weights
Agricultural land use sub-indicator
Raw water quality sub-
indicator
Disinfection-related sub-
indicator
Infrastructure and maintenance sub-
indicator
Utility performance sub-indicators
Variables
÷ 2 × 2 ÷ 2 × 2 ÷ 2 × 2 ÷ 2 × 2
Agricultural land use sub-
indicator
Raw water quality sub-
indicator
Disinfection-related sub-
indicator
Infrastructure and maintenance
sub-indicator
Agricultural land use sub-indicator
Agricultural pressure (P2O5) 0.025 0.1 0.065 0.05 0.07 0 0.06 0.05 0 0.1 0.1 0.07
TOC of raw water 0.03 0.03 0.015 0.06 0.07 0 0.05 0.03 0.03 0 0.1 0.07
Turbidity of raw water 0.03 0.03 0.015 0.06 0.07 0 0.05 0.03 0.03 0 0.1 0.07
Total coliform bacteria in raw water 0.055 0.05 0.025 0.1 0.07 0 0.05 0.05 0.06 0 0.1 0.07
HPC bacteria in raw water 0.03 0.02 0.01 0.04 0.07 0 0.05 0.02 0.03 0 0.1 0.07
Raw water quality sub-indicator
Atypical bacteria in raw water 0.03 0.02 0.01 0.04 0.07 0 0.05 0.02 0.03 0 0.1 0.07
CT value 0.4 0.35 0.4 0.25 0.2 0.7 0.4 0.2 0.4 0.4 0 0.4
Frequency of residual chlorine checking
0.12 0.12 0.12 0.12 0.06 0.2 0.12 0.1 0.12 0.12 0 0.12 Disinfection-related sub-indicator
Appropriateness of residual chlorine checkpoints
0.06 0.06 0.06 0.06 0.03 0.1 0.06 0.06 0.06 0.06 0 0.06
Utility age 0.04 0.04 0.07 0.04 0.07 0 0.02 0.08 0.05 0.08 0.1 0
Pipe material 0.08 0.08 0.08 0.08 0.08 0 0.04 0.16 0.08 0.08 0.1 0
Pipe breakage 0.06 0.06 0.06 0.06 0.07 0 0.03 0.12 0.06 0.08 0.1 0
Infrastructure and maintenance sub-indicator
System flushing 0.04 0.04
0.07 0.04
0.07 0
0.02 0.08 0.05 0.08 0.1 0
163Table H.2. Sensitivity analysis of the utility performance indicator (indicator values)
Variation of utility performance sub-indicator weights Exclusion of respective sub-indicators
Agricultural land use sub-indicator
Raw water quality sub-indicator
Disinfection-related sub-indicator
Infrastructure and maintenance sub-
indicator
Utilities
÷ 2 × 2 ÷ 2 × 2 ÷ 2 × 2 ÷ 2 × 2
Agricultural land use sub-
indicator
Raw water quality sub-
indicator
Disinfection-related sub-
indicator
Infrastructure and maintenance
sub-indicator
I. 54 C 58 C 56 C 56 C 57 C 50 C 55 C 57 C 53 C 57 C 60 C 55 C
II. 76 B 75 B 78 B 74 B 69 B 77 B 70 B 79 B 77 B 78 B 65 B 66 B
III. 68 B 72 B 67 B 74 B 73 B 60 C 69 B 74 B 67 B 67 B 77 B 70 B
IV. 58 C 63 B 59 C 67 B 70 B 37 D 56 C 72 B 57 C 60 C 82 A 55 C
V. 92 A 92 A 91 A 91 A 88 B 95 A 92 A 89 B 91 A 91 A 85 A 92 A
VI. 80 B 76 B 76 B 78 B 78 B 85 A 82 A 71 B 81 A 72 B 75 B 86 A
VII. 63 B 61 B 60 C 70 B 73 B 42 C 59 C 75 B 64 B 57 C 85 A 58 C
VIII. 56 C 55 C 51 C 65 B 65 B 42 C 57 C 62 B 57 C 47 C 75 B 60 C
IX. 59 C 56 C 55 C 68 B 68 B 42 C 57 C 69 B 61 B 51 C 77 B 56 C
X. 52 C 50 C 48 C 63 B 66 B 25 D 48 C 69 B 54 C 45 C 82 A 46 C
75† B 75 B 74 B 78 B 76 B 69 B 73 B 79 B 75 B 73 B 78 B 71 B Overall performance indicator
60‡ C
60 C
58 C 67 B
67 B 47 C
59 C 67 B 61 B 55 C 75 B 60 C
† Nonproblematic utility group ‡ Problematic utility group
