Greywater application

Greywater Technology Testing Protocol

Clare Diaper, Melissa Toifl and Michael Storey December 2008

Water for a Healthy Country Flagship Report series ISSN: 1835-095X

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Citation: Diaper, C. Toifl, M and Storey, M (2008) Greywater Technology Testing Protocol. CSIRO: Water for a Healthy Country National Research Flagship

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Acknowledgements

The authors of this report would like to thank all other CSIRO team members who have provided input into this project: Roger O’Halloran, Grace Tjandraatmadja, Michelle Critchley and Yesim Gozukara.

The project team would like to thank Smart Water Fund and the water companies represented by this body: City West Water, South East Water, Yarra Valley Water and Melbourne Water Corporation, for their financial support in this project.

Everwater, Sampford and Sons, and New Water are gratefully acknowledged for providing technologies to test and the resources to commission them.

CSIRO would also like to thank the EPA (Environment Protection Authority Victoria) and DHS (Department of Human Services) for their contributions to the development of this protocol, Ecowise for information on field testing of greywater technologies and other manufacturers who provided greywater quality data.

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Executive Summary

This report provides details of a proposed laboratory based greywater technology testing protocol and details the recommended procedures, methods and analysis techniques for this process. This is a draft methodology and should be viewed as such, its purpose being a discussion document to be circulated to regulatory bodies, councils, system manufacturers and other stakeholders for comment and discussion. The report includes a description of the protocol as well as details of the processes that were followed during protocol development and the rationale of decisions and recommendations.

The protocol was developed by testing three small scale greywater treatment systems (Table A and (Diaper C. and Toifl M. 2006; Diaper C. et al. 2006; Diaper C. and Toifl M. 2007)) which combined different chemical, physical and biological processes to achieve performance requirements. The technologies were selected on the basis of these unit processes in order to ensure the protocol was appropriate for the different process types.

Table A: Technologies tested during protocol development

Technology Process type

Treatment process Disinfection process

A Semi batch Biological with suspended media UV

B Batch Chemical flocculant dosing, UV and four stage filtration

UV

C Semi batch Settling, biological with fixed media Chemical (Cl/Br)

The testing was undertaken in a PC2 (Physical Containment Level 2) laboratory under controlled conditions. The following basic equipment was required for testing:

• Feed tank (1000 L capacity recommended)

• Submersible pump for mixing greywater

• Greywater feed pump (specifications dependent on technologies tested and laboratory setup)

• Pressure rated dosing pump for inoculum dosing

• Online flow meter or rotameter (flow range dependent on technologies tested)

• Effluent storage tanks to allow disinfection of treated greywater.

The technologies were fed with a synthetic greywater which mimicked an average combined laundry and bathroom greywater from an Australian residential dwelling. The components of the greywater included a range of market share household products, some laboratory grade chemicals and secondary sewage effluent sourced from a local wastewater treatment plant (Eastern Treatment Plant, Melbourne). The quality parameter ranges for suspended solids, biological oxygen demand (BOD), temperature, pH, turbidity, sodium, zinc, total phosphorous total Kjeldahl nitrogen (TKN), conductivity, chemical oxygen demand (COD), total organic carbon (TOC), total coliforms and E.coli were selected following review of Australian and international literature and analysis of data collected from Australian case studies. Whilst calcium and magnesium were analysed in the synthetic greywater, parameter ranges were not specified as these will vary and is dependent on mains water quality. Aluminium was also measured but has no specific parameter range as this will be highly dependent on the household products used.

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Three stages of testing were proposed as follows:

• Tracer study

• Chemical testing

• Microbiological testing.

The tracer study provided a profile of technology flow conditions and was used to develop flow and dosing regimes for chemical and microbiological testing. The tracer used in the testing of the three greywater technologies was sodium chloride, as simple monitoring of outlet concentrations was possible and the concentrations used did not affect biological treatment.

The parameters selected for chemical testing were based on a literature review of components of greywater and investigation of greywater components likely to have detrimental impacts on soils, plant life and other water bodies. The water quality parameters analysed in the feed and product streams during chemical testing were the same as those for the synthetic greywater with the addition of nitrate and F.Enterococci, and the exception of temperature. The basic micro-organism analysis was carried out during chemical testing as secondary effluent was added to the synthetic greywater and the performance of the technology could be clarified prior to dosing high micro-organism concentrations.

The purpose of the microbiological testing was to prove a log removal of bacterial, protozoan and viral surrogates. The micro-organisms selected were in accordance with those suggested in national water recycling guidelines (Environment Protection and Heritage Council et al. 2006). During protocol development a helminth surrogate, latex fluorospheres, was trialled but analysis techniques were time consuming and of limited accuracy, and the proof of log removal was inconclusive. As helminth ova are unlikely to be prevalent in greywater in Australia it is recommended this surrogate is rejected as a testing requirement.

The bacterial surrogates used were Escherichia coli (ATCC 25772) and Enterococcus faecalis (ATCC 19433) as both are recommended strains for use with Colilert tests kits (IDEXX Laboratories), the selected analysis technique. Inoculum concentrations of > 106 cfu/100mL were required in order to prove a 7 log removal (minimum detection 100 cfu/100mL).

The viral surrogates selected were the bacteriophages MS-2 and ΦX174, a somatic and an f-specific RNA phage respectively. Although the phages are similar in size (24 and 27 nm respectively), they have different isoelectric points (ΦX174 pI = 6.6 and MS-2 pI = 3.9) (Dowd S.E. et al. 1998; Dowd et al. 1998). The reason for basing selection on charge rather than size was that, for the greywater treatment technologies currently on the market in Australia, removal at the molecular level will be predominantly influenced by charge rather than size. Product water samples were assayed for MS2 and ΦX174 phage, either in-house or by a NATA accredited laboratory, using the ISO standard methods for MS-2 (International Standard Organisation 1995) and ΦX174 (International Standard Organisation 2000). The concentrations of each phage had to be at least 106 so that log 7 removal could be proven by any system tested.

Clostridium perfringens was selected as the surrogate for Cryptosporidium oocysts. The spores were prepared from frozen stocks obtained from the culture collection held by the University of NSW and product samples were analysed using the method described in AS/NZS 4276.17.1 (2000) (Australian Standard 2000). One litre sample volumes were used, as previous work had indicated that the product samples collected required concentration, rather than the dilution, described in the standard method. Concentrations of spores in the inoculum were in the range of 105 to 106 spores/100mL so that 7 log removal could be proven.

Technologies are challenged with repeated high feed concentrations of the different micro-organism surrogates, the number of repetitions and product sample analysis dependent on the technology and the results of the tracer study. Collection of proportional volume feed and product samples, rather than spot samples, is recommended.

The three stages of testing outlined in the protocol provided:

• Hydraulic integrity testing of the technology

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• A check of performance in removal of greywater components that are harmful to the environment

• Proof of performance of a technology in the removal of a range of surrogate micro-organisms

• Some assessment of operational issues.

As such, the protocol is appropriate for testing technologies for High Exposure Risk end uses, such as residential dual reticulation, multi-unit dwellings and unrestricted access urban irrigation, as outlined in the National Water Recycling Guidelines (Environment Protection and Heritage Council et al. 2006)

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Table of Contents

Introduction .............................................................................................................. 1 1. Rationale............................................................................................................ 2 2. Experimental set up.......................................................................................... 5

System requirements............................................................................................................5 3. Synthetic greywater.......................................................................................... 7

3.1. Recipe....................................................................................................................... 7 3.2. Procedure ................................................................................................................. 7 3.3. Quality....................................................................................................................... 9

4. Tracer study .................................................................................................... 11 5. Chemical testing ............................................................................................. 13

5.1. Method....................................................................................................................13 5.2. Results ....................................................................................................................14

6. Microbiological testing................................................................................... 16 6.1. Bacterial dosing method .........................................................................................16 6.2. Virus surrogate dosing method...............................................................................17 6.3. Protozoa surrogate dosing method ........................................................................18 6.4. Helminth surrogate dosing method.........................................................................18 6.5. Micro-organism dosing results................................................................................18

7. Reporting......................................................................................................... 20 8. Discussion and recommendations ............................................................... 21 9. Future work ..................................................................................................... 23 Appendix 1 – Synthetic greywater components ................................................. 25 Appendix 2 – Estimation of amount of products used....................................... 29 Appendix 3 – Properties of Unimin clay .............................................................. 30 Appendix 4 – Real greywater quality ................................................................... 31 Appendix 5 – Modifications to synthetic greywater recipe................................ 33 Appendix 6 – Changes in parameter ranges for large scale batches using different synthetic greywater formulations ......................................................... 34 References.............................................................................................................. 35

TABLES

Table 1: Summary of technologies tested during protocol development ......................................3 Table 2: Final synthetic greywater recipe (formulation 4) .............................................................8 Table 3: Parameter ranges and quality of synthetic greywater ...................................................10 Table 4: NATA laboratory results of chemical and bacterial testing ...........................................14 Table 5: Example results of micro-organism log removal for Technology C...............................19 Table 6: Example of HAZOP assessment method .....................................................................23 Table 7: Synthetic greywater parameter ranges compared to Australian greywater data ..........31 Table 8: Australian greywater quality data..................................................................................32

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FIGURES

Figure 1: Technologies tested during protocol development (L to R, Technology A, B and C) ....6 Figure 2: Schematic of the system layout .....................................................................................6 Figure 3: Tracer study outlet Electrical conductivity – Technology A..........................................12 Figure 4: Tracer study outlet Electrical conductivity – Technology C .........................................12

Greywater Technology Testing Protocol 1

Introduction

The first section of this report introduces the background to the project and the reasons for and the requirements of the greywater testing protocol development in the Rationale (Section 1). The experimental set up is then described, providing details of equipment and facilities used in the testing of three greywater treatment technologies (Section 2).

The synthetic greywater recipe is then described, with details of component contributions, procedures for the generation of synthetic greywater and the results of water quality analysis of large scale batches of greywater (Section 3).

The next three sections describe the testing protocol and its components. The testing protocol comprised of three analytic processes:

• Tracer study


• Microbiological testing.

Section 4 describes the tracer study testing that was required for each technology prior to starting performance testing. The tracer study was required in order to understand the flow profiles of the technology being testing and to develop the subsequent chemical and microbiological testing regimes.

The chemical testing requirements are then described (Section 5), followed by experimental details of the microbiological dosing with Escherichia coli and Enterococcus faecalis, MS2 and φX174 coliphages and protozoa surrogates (Section 6).

Section 7 outlines possible reporting requirements for the testing of greywater systems, developed from the summary reports of the three technologies tested during the development of the protocol.

Section 8 provides recommendations for the future development of the protocol to a national standard. Section �9 describes a proposed desk-based risk assessment to be carried out in conjunction with the laboratory based testing which will provide a more complete assessment of technologies under a range of operating conditions.


1. Rationale

The aim of this project was to develop a practical, robust and reproducible method for testing greywater treatment technologies to Australian recycled water standards, proving log removal of bacteria, virus, protozoa and helminth surrogates. There is no standard national testing method for greywater technologies in Australia and the research undertaken aids in the development of appropriate protocols and procedures for different scales of treatment and end uses of greywater. The processes used are in line with the risk assessment approach of the National Water Recycling Guidelines (Environment Protection and Heritage Council et al. 2006). The work was funded by Smart Water Fund and CSIRO Water for a Healthy Country Flagship.

There is currently much focus, both nationally and internationally, on water saving measures, better management of water supplies and implementation of policies to reduce wastewater discharges to receiving waters. The use of alternative source waters, such as greywater, is being investigated and there are a wide range of technologies commercially available for greywater treatment. In Australia, numerous strategies that include greywater treatment systems for water recycling in the home are being supported by government agencies (Victorian Government Department of Sustainability and Environment 2004; New South Wales Government 2006). This has led to an increased interest in developing new greywater recycling technologies.

Despite the perceived innocuous nature of greywater, it can contain enteric bacteria, viruses and intestinal parasites which may be pathogenic (Casanova et al. 2001; Birks and Hills 2007; Winward et al. 2007). Previous studies have found increased risks to human health from viral, but not bacterial, pathogens when using greywater for accidental direct contact, sportsfield irrigation and groundwater recharge with greywater (Ottoson and Stenstroem 2003). However, before widespread adoption of domestic greywater systems is approved, it is essential that thorough, robust and reproducible testing procedures are developed in order to ensure that there is no increase in human health risk.

In Australia, there are no national guidelines for testing of household greywater systems, and different states have different protocols and procedures for testing. At the single household scale there are prescriptive standards for technology accreditation (New South Wales Health Department 2005). It is often recommended that the accreditation be used in conjunction with guidance documents for greywater use in single household residential premises (New South Wales Department of Energy Utilities and Sustainability 2007). The NSW single household domestic greywater accreditation is based on a 26 week field monitoring period of greywater treatment systems in a household of eight to ten people (or 720 to 900 L/day greywater flow) and includes thermotolerant coliform (TC), Biological Oxygen Demand (BOD5), suspended solids (SS), free chlorine, total Kjeldahl nitrogen (TKN), total nitrogen (TN) and total phosphorus (TP) analysis. However, there is currently no recommended testing for pathogenic micro-organisms.

For multi-dwelling premises, guidance (New South Water Health 2005) is in the form of a framework for the assessment of recycled water schemes, and is not prescriptive in testing requirements (New South Wales Department of Water and Energy 2007). The NSW guideline recommends validation, verification and operational monitoring requirements based on the exposure risk level of the end use of the recycled water. Monitoring is recommended for the highest exposure risk level (for internal use and unrestricted irrigation) of BOD5; pH; SS; turbidity; free chlorine (or other disinfection system efficiency); and the micro-organisms E.coli, coliphages and Clostridia.


The monitoring programs suggested for both single residential and multi-dwelling premises do not necessarily validate the performance of the technology for pathogen removal. The recommended field testing will not necessarily challenge the technology with high concentrations of pathogenic micro-organisms in the feed stream, therefore maximum log removal cannot be assessed.

In order to address this potential issue of system performance validation and to enable a wide range of likely conditions to be assessed, the approach taken in this study was to use a laboratory based testing process rather than field tests, to validate the performance of greywater treatment technologies. Three different greywater treatment technologies were used in the development of the protocol. Technologies were selected based on their method of processing: one semi-batch biological and UV disinfection process, a batch chemical and physical separation process with UV disinfection and a semi-batch biological process with chemical disinfection (Table 1). This range of process types allowed investigation of the appropriateness of selected surrogate micro-organisms and the suitability of the protocol to different process types.

Table 1: Summary of technologies tested during protocol development

Technology Process type

Treatment process Disinfection process

Maximum Flow rate (L/day)

A Semi batch

Biological with suspended media

UV 600

B Batch Chemical flocculant dosing, UV and four stage filtration

UV 1000

C Semi batch

Settling, biological with fixed media

Chemical (Cl/Br)

300

Section 3 outlines the development of a synthetic greywater, which contains a variety of personal hygiene and household products, secondary treated effluent and clay. The formulation was based on an assessment of the market share of household products used in Australia (IbisWorld 2005), literature values of per capita water usage for different appliances and a review of real greywater quality in Australia (Appendix 4). Advantages of a synthetic formulation are that quality is consistent, parameters can be adjusted and controlled easily and comparative research assessment is possible. Real greywater has been used for research purposes in previous studies (Birks R. et al. 2004; Jefferson et al. 2004), but it is variable in quality and may be impractical to collect and store, limiting the feasibility of the assessment process. A further benefit of using synthetic greywater is that methods are easily repeatable by others, which achieves one of the objectives of the protocol. A synthetic greywater will allow other users to test systems with a standard feed quality. A disadvantage of synthetic greywater is that it will not mimic the variability in quality observed in real greywater. A possible approach for addressing this issue is suggested in Section �9, which outlines a risk assessment approach for assessing the impact of changes in greywater flows or quality.

The quality parameter ranges of the synthetic greywater used in this study were selected to mimic the quality of real greywater. Initially, quality data collated from international literature was used as the basis for parameter ranges. This was updated with current data collated on Australian greywater in order to ensure the quality parameters correlated to an average Australian residential greywater quality.

Surrogate micro-organisms for bacterial, viral, protozoan and helminth pathogens were used to assess greywater technology performance and were chosen in consultation with the


Victorian EPA, DHS and Smart Water Fund. The use of surrogate organisms had the advantage of reduced Occupational Health and Safety requirements compared with the use of viable pathogens. This means testing facilities did not have to comply with high levels of microbiological containment and allowed simpler, more easily transferable testing methods to be developed. Development of a robust and reproducible testing protocol will depend on the ease of use and quantification of the microbial species and surrogates used. Surrogates have been used in previous studies with greywater (Rose et al. 1991; Ottoson and Stenstroem 2003).

The test method was developed as a three-stage process: tracer study testing, chemical testing and microbiological testing. The tracer study allowed assessment of the hydraulic integrity of the technology and provided the basis for flow, inoculum dosing and sample collection frequency requirements of the chemical or microbiological testing. The chemical testing included a range of physical, chemical and microbiological parameters which provided an indication of potential environmental and human health risks, as well as an assessment of system operational performance. The microbiological testing was designed to prove compliance with the log removal requirements for the selected surrogates recommended in recycled water guidelines (Environment Protection and Heritage Council et al. 2006). This three-stage approach allowed verification of system performance prior to the more complex and costly microbiological testing.


2. Experimental set up

System requirements The basic testing system components were (Figure 2):

• Physical Containment Level 2 (PC2) laboratory

• Feed tank

• Submersible pump for mixing

• Feed pump (specifications dependent on technologies tested and laboratory setup)

• Pressure rated dosing pump

• Online flow meter (flow range dependent on technologies tested)

• Effluent storage tanks.

Online monitoring of pH, conductivity and turbidity were suggested in order to allow continuous monitoring of synthetic greywater feed. However, spot samples could be taken and analysed to ensure consistency in feed quality.

The micro-organisms used for testing the greywater technologies are listed as Class 2 in the AS/NZ Standard 2243.3:2002, ‘Safety in laboratories - Microbiological aspects and containment facilities’ and a PC2 (Physical Containment Level 2) facility was required for the testing process.

For the development of the synthetic greywater and testing of three greywater treatment technologies used to develop and validate the protocol, a 1000 L custom built feed tank was used. A tank of this volume was required so large scale batches of the greywater could be produced and tested. A submersible pump (a Grundfos AP12 40 04A1V with vortex impellor was used in this study) in the feed tank was used to continually mix the synthetic greywater for a minimum nine hour period prior to use. A T-piece pipe was connected to the outlet of the pump in order to ensure flows were tangential to the walls of the tank to aid in surface scouring and reduce foam generation. Mixing of the greywater prior to use increased the temperature of the greywater and lowered the pH to the required parameter range (Table 3, Section 3.3)

The flow of the greywater feed to the technology was monitored using a rotameter or an online mag-flow meter (a Turbo KP-G polypropylene lined meter was used in this study). Flows were adjusted using two valves and a recycling loop back to the feed tanks. The feed pump used in this study was a Davey M3061-0 with Torrium priming and a maximum flow of 5000 l/hr and 69 m maximum head. Volumes of synthetic greywater fed to the technology during testing were monitored via a simple level measurement of the feed tank and crosschecked with the rotameter or flowmeter. Temperature, pH, conductivity and turbidity were monitored online prior to a sampling point, installed between the feed tank and the technology.

The three technologies (Figure 1) were installed by manufacturers and distributors and were tested as installed. Any operational or maintenance issues during the testing were addressed by the manufacturer.


Figure 1: Technologies tested during protocol development (L to R, A, B and C)

Product samples were taken as spot samples or as a proportion of the total outlet flow, depending on the technology. A peristaltic pump was used for taking the proportional samples. This is the recommended method for sample collection, providing details of outlet flow are available and outlet flows are relatively constant.

One technology tested had a final product storage tank as an integral component of the technology (Figure 1, Technology A). (It is recommended that product samples are taken prior to any final storage of treated greywater in order to test technology performance, rather than the effect of storage, on treated greywater.)

Figure 2: Schematic of the system layout

Online monitoring of

pH, conductivity, temperature

Rotameter or flow meter

Mixing tank

(1000 L)

Submersible mixing pump

Feed pump

Clay, effluent and

micro-organism

dosing point using dosing

pump

Sampling point Technology to

be tested or holding tank


3. Synthetic greywater

The synthetic greywater formulation was a modified version of a recipe developed and used for testing greywater systems in the UK (Brown R. and Palmer A. 2002). The composition of greywater has been found to vary significantly between countries and regions (Siegrist R.L. et al. 1976; Brandes 1978; Walpole and Hartley 1993; Eriksson et al. 2002). There are a number of reasons for this variability: use of different household products (and the different composition of products); varying tap water qualities and water usages; different householder behaviours; and the inclusion or exclusion of various waste streams in the greywater, laundry only, bathroom only or laundry and bathroom combined. These factors suggest that careful consideration needs to be given before using a formulation that has been developed in another country or region.

There were a number of requirements for synthetic greywater formulation for technology testing:

• Mimic real greywater in composition

• Provide a matrix that allows micro-organism and pathogen survival

• Contain compounds in detectable concentrations identified as having detrimental environmental impacts in real greywater

• Be reproducible and provide consistent quality between batches and between users.

3.1. Recipe

To meet the above requirements the formulation developed contained products expected to be found in average Australian households, including personal care products and detergents and additional laboratory chemicals in order to achieve the concentration ranges of various parameters as required. Market share products were used where data was available (Appendix 1 – Synthetic greywater components). Estimations of amount of products used were made and combined with average water usage data in order to calculate the amount of product to be used in the recipe (Appendix 2).

3.2. Procedure

To prepare the synthetic greywater all ingredients, except the clay and secondary effluent, were weighed and mixed with 500 mL warm water in a blender at low speed for one minute. The quantities given in the table below are for 100 L of greywater. The feed tank was filled with the required amount of tap water and the concentrated ingredient mixture added. A submersible pump in the feed tank was used to mix the greywater overnight or for at least nine hours. Mixing the greywater for at least nine hours was found to decrease the pH into the correct range (Table 2) and also brought the temperature of the greywater into the desired range of 25-35°C. The outlet of the pump in the feed tank required some modification to direct the outlet towards the feed tank walls to reduce entrainment of air and foaming in the feed tank.


Table 2: Final synthetic greywater recipe (Formulation 4)

Ingredient Amount in 100L (g)

unless otherwise stated

Product used

Sunscreen

OR

1.5 UV TripleGuard

Moisturiser 1 Dove

Toothpaste 3.25 Colgate Maximum Cavity Protection (regular)

Deodorant 1 Mum

Na2SO4 3.5 Analytical grade

NaHCO3 2.5 Analytical grade

Na2PO4 3.9 Analytical grade

Clay (Unimin)1 5 Industrial grade

Vegetable Oil 0.7 Coles Own brand

Shampoo/hand wash 72 Palmolive

Laundry 15 Omo High Performance/ Omomatic concentrate

Boric acid2 0.14 Analytical grade

Lactic acid 2.8 Analytical grade

Secondary effluent3 2 L Eastern Treatment Plant at Carrum (from secondary clarifier)

1 The properties of the Unimin clay are given in Appendix 3 2 Addition dependent on boron detection limit 3 Secondary effluent was stored (< 4°C) and used within 2 weeks of collection

The clay and secondary effluent were mixed together and stirred using a magnetic stirrer for at least 15 mins prior to and during feed of the greywater technology. The clay and secondary effluent mixture was added in–line via a peristaltic pump, as adding clay to the feed tank increased adhesion of clay to the feed tank’s walls and fitting. Any micro-organism inocula (bacteria, virus, protozoa and helminth surrogates) used for testing the greywater technologies were also added to the effluent and clay prior to dosing. Secondary effluent was allowed to reach room temperature prior to dosing or addition of microbial inocula in order to reduce the potential for damage to the micro-organisms due to a rapid change in temperature.

This mix of freely suspended micro-organisms and micro-organisms associated with particulate material provided an assumed worst case scenario for testing; the micro-organisms not bound to particulate being the smallest and more likely to pass through filtration process, the bound micro-organisms being shielded from chemical and physical disinfection process if they are not removed by filtration. Further analysis of the ratio of


micro-organism to clay concentrations is required in order to ensure a mix of suspended and particulate associated micro-organisms.

Subsequent review of published literature suggests that native micro-organism populations can have a significant influence on the survival of introduced micro-organisms (Walter et al. 1995). This needs further clarification but it is recommended that when dosing micro-organism inocula, secondary effluent is not added to the synthetic greywater.

3.3. Quality

Table 3 shows the expected water quality parameter ranges for the synthetic greywater produced using the recipe given in Table 2. The target parameter ranges (Table 3) used for the synthetic greywater formulation were based primarily on Australian greywater quality data. Initially data from the ‘Smart Water Fund Testing Protocol for proposed technologies treating greywater’ was used to set parameter ranges (source data from (Jeppesen 1996)) but there were limitations in using this data, primarily that it was over ten years old. Thus, the data sources were extended to other current Australian data collected from system technology manufacturers and Ecowise (Appendix 4) and international literature (Eriksson et al. 2002). Following this review, the median of the parameters ranges for BOD, turbidity, sodium and conductivity were reduced. Further investigation of total-N and total-P ranges is required as the median and averages for the current data analysed were significantly different from the initial parameter ranges suggested by Smart Water Fund (see Appendix 4).

The results of the analysis of initial large scale batch testing showed that several parameters were outside of the desired range. Several new ingredients were added and the quantities of some of the existing ingredients in the recipe were adjusted on subsequent batches until the results from the final large scale batch testing showed that the chemical and physical parameters were all within the expected range (Table 3). The adjustments to the recipe are shown in Appendix 5 and the results of the corresponding large scale batches are shown in Appendix 6. The chemical components of the recipe were found to be reproducible between batches, with the results in Table 3 showing the average and standard deviation for the final formulation (presented in Table 2). Results are an average of five batches for the formulation.

The microbiological parameters were more difficult to adjust and were largely dependent on the concentration of micro-organisms present in the secondary treated effluent, which can vary. Whilst the E.coli concentrations were in the desired range, the total coliform concentration was 103 times the desired range. Coliforms are abundant in the environment and are commonly found in the faeces of warm blooded animals, in aquatic environments, in soil and on vegetation. This abundance of coliforms in the environment may account for the higher than expected levels of total coliforms in the synthetic greywater.


Table 3: Parameter ranges and quality of synthetic greywater

Parameter Original range (Jeppesen

1996)

Updated range Appendix 3 (mg/L

unless otherwise stated)

Results from final large scale batch (Formulation 4)

Suspended solids 60 - 80 60 - 80 59.0 ± 3.3 BOD 150 - 200 130 - 180 146.7 ± 5.0

Temperature 20˚ - 30˚C 25˚ - 35˚C pH 6.5 – 8.0 6.5 – 8.0 7.4 ± 0.1

Turbidity 60 – 80 NTU 50 – 70 NTU 52.1 ± 4.6 Boron 0.1 – 0.5 0.1 – 0.5

Sodium 80 – 130 50 – 90 65.3 ±1.0 Calcium - - 7.6 ± 0.3

Magnesium - - 1.3 ± 0.1 Aluminium - 1.6 ± 0.4

Zinc 0.1 – 0.5 0.1 – 0.5 Total phosphorous-P 10 – 20 10 – 20 17.8 ± 0.4

Total Kjeldahl nitrogen-N

3.0 – 5.0 3.0 – 5.0 3.0 ± 0.1

Nitrate <0.2 Nitrite <0.003

Conductivity (μS/cm) 450 - 550 300 - 400 322.2 ± 6.7 COD 250 - 400 250 - 400 276.7 ± 21.0 TOC 50 - 150 50 - 150 62.6 ± 12.7

Total coliforms (cfu/100mL)

103 – 104 103 – 104 106 – 107

E.coli (cfu/100mL) 101 - 102 102 – 103 102 – 103 F.Enterococci (cfu/100mL)

1-100


4. Tracer study

A tracer study was used to determine the profile of flow for each technology prior to commencing chemical and microbiological testing. The choice of tracer was discussed with the technology manufacturers prior to commencing the tracer studies to ensure that it would not interfere with the process of the technology or damage any media or bacterial growth on any media utilised. The tracer selected for the three technologies tested during the development of the protocol was sodium chloride.

Initially, the sampling and run-time procedures of the testing protocol were to be based on the theoretical hydraulic retention time (HRT), θS (where θS= VT/Q, and VT is the total volume of greywater storage within a technology and Q is the rate of feed to the technology). However, the different types of treatment technology to be tested used numerous filtration and media types, which made estimation of greywater storage volume difficult and so the tracer study technique was utilised.

The tracer studies were carried out by adding a salt dose to the first batch of water fed to the technology and then feeding further batches of clean water until the conductivity at the outlet of technology returned to background levels. The sodium chloride concentrations used did not affect the treatment processes and conductivity probes were used to continuously monitor and record the effluent during the tracer study. Other tracers could be used, such as Rhodamine B, if there were concerns regarding the effects on the process.

The results of two technology tracer studies are presented in order to demonstrate the use of the method in developing sampling and run time protocols. Figure 3 shows tracer study testing results from Technology A, the semi-batch process greywater treatment technology, to which one 150 L batch of high salt content feed was added. The technology was then fed with ten subsequent 150 L batches of potable water per day over a period of three days. The technology maximum daily flow rate was stated as 600 L/day (N.B. The constant conductivity readings observed between the first and second and the second and third days are due to the technology being shut down overnight.

The results show conductivity breakthrough observed at outlet at ~ 6 hours, during the second feed batch of potable water to the technology. The maximum concentration at the outlet was observed after 9.5 hours, or an additional batch time. This information was then used to determine the feed inoculum and product sample collection to be used when testing the performance of the technology in the removal of micro-organisms. From examining the tracer study outlet profile the proposed microorganism test method for this first technology was:

• Feed high inoculum dose until the tracer study peak product concentration is achieved i.e. feed high inoculum dose for three 150 L batches

• Continue to analyse product samples until the tracer study concentration returns to background levels i.e. collect product samples for a minimum of ten 150 L greywater batches

Operating the testing in this manner aids in proof of log removal during testing and ensures that all potentially contaminated product is analysed. Further statistical analysis of the number of samples and replicates is required to ensure the testing regime demonstrates log removal.

The results of a salt tracer study for Technology C, operating on a batch cycle, is shown in Figure 4. The design of this technology was such that there was a small residual storage at the end of processing, therefore the conductivity does not return to zero after the first batch. After three consecutive salt-free feeds, the conductivity of product returns to background levels.


0

200

400

600

800

1000

1200

0.00 12.00 24.00 36.00 48.00 60.00Time (hours)

Con

duct

ivity

(µS/

cm)

Feed 1

Feed 2

Feed 3

Feed 4

Feed 5

Feed 6

Feed 7

Feed 8

Feed 9

Feed 10Feed 11

Feed 12

Unit on standby

overnight

Unit on standby

overnight

Figure 3: Tracer study outlet Electrical conductivity – Technology A

0

200

400

600

800

1000

1200

1400

0 2 4 6 8 10 12 14 16 18 20Time (hours)

Elec

tric

al C

ondu

ctiv

ity (µ

S/cm

)

Feed 1 - 100 Feed 2 - 100 Feed 3 - 100

Figure 4: Tracer study outlet Electrical conductivity – Technology C

When testing this system for removal of micro-organisms, inoculum was dosed for three feed cycles and product was collected for a total of six feed cycles (twice the number observed for the tracer study outlet concentration to return to background levels). This was done to ensure any micro-organisms that may be entrained in the technology media would be detected and was a different rationale to that used for the first technology.


However, although knowledge of the entrainment of micro-organisms provides insight into the mechanisms of removal, it is not necessarily required to prove the performance of the technology in terms of log removal of micro-organisms. Thus, the recommendation for the protocol based on the results of tracer study is to feed high inoculum dose AND continue to analyse product samples until the tracer study concentration returns to background levels, as was the rationale used for Technology A.

5. Chemical testing

5.1 Method

Chemical components analysed for all of the technologies tested are shown in Table 4. The parameters were selected based on a literature review of components of greywater and investigation of greywater components likely to have detrimental impacts on soils, plant life and other water bodies (Jeppesen 1996). The soil type to which the greywater is applied will have an effect on the impacts of different chemical constituents. In general, clayey soils are more affected by high salinity, sodicity and metals, and there is the possibility of eutrophication of surface waters. On the other hand, in sandy soils all these parameters are more likely to affect the groundwater.

Analysis of suspended solids was carried out as part of the chemical testing for each technology as it provided an indication of the propensity of the treated greywater to cause physical blockage of soil pores or blockage of irrigation systems. Turbidity was also measured, as this is an easy way to measure indicators of colloidal and suspended residual material, and provides a quick check of technology performance.

The electrical conductivity was measured as a surrogate measure for total dissolved solids, which provides a measure of the dissolved salt content or salinity. Salinity will effect both plant growth and soil structure. pH can also impact plant growth and soil structure and also provides an easy check that a technology is operating correctly.

The total organic carbon (TOC), chemical oxygen demand (COD) and biological oxygen demand (BOD5) were included as they provide a good surrogate measurement of biologically degradable, organic and non biologically degradable components.

Total phosphorous and total nitrogen were analysed during testing as these parameters provide a measure of the nutrient content of the treated water. Both nitrogen and phosphorous are required for plant growth but can cause detrimental effects to both plants and open water bodies if present in excessive quantities. In addition, both parameters provide an indication of the propensity for biological regrowth in the treated water. Nitrate was also measured as this provides an indication of technology performance. The measurement of calcium and magnesium in conjunction with nitrogen and phosphorous will give an indication of the potential benefits of greywater use to plant growth.

Testing for calcium, magnesium and sodium was undertaken in order to obtain a value for sodium adsorption ratio (SAR), an indicator used to assess the impacts of treated water on soil infiltration. Zinc was also included as levels approaching or above the guideline values for irrigation have been found in greywater (Christova-Boal, 1996; Hypes, 1974). Aluminium is often present in personal care products so was also included in the testing.

Total coliforms, E.coli and F.Enterococci, were also monitored during chemical testing, as secondary effluent was added to the feed. This gave a preliminary indication of technology performance for bacteria removal and ensured the technology was operating correctly.


Chlorine and bromine residual analysis was undertaken in-house where necessary. Transport times to the external laboratory made NATA testing of chlorine and bromine impracticable. Results are not reported here as they are not NATA accredited, but the inclusion of these parameters for analysis when the tested technology utilises chemical disinfection, is recommended.

5.2 Results

Testing for chemical and physical parameters was carried out for each technology on the feed and product water and included suspended solids, biological oxygen demand (BOD), conductivity, pH and turbidity (see Table 4 for full list). The samples were analysed by a NATA accredited laboratory. The pH, conductivity, temperature and turbidity of the greywater feed were also monitored throughout all trials using on-line probes. Boron was included in initial analysis as it may be present in laundry detergents and is known to have acute toxicity to plants. Boron concentrations found in greywater (Friedler 2004) are often above the recommended maximum value for irrigation waters (Environmental Protection Authority Victoria 1991). However, the boron analysis method selected by the laboratory employed to carry out the sample analysis was not particularly sensitive and was not able to detect levels below 1.2 ppm. As the levels of boron in the greywater were below this limit they were not detected and therefore results for boron are not available.

Table 4: NATA laboratory results of chemical and bacterial testing

Parameter Units Average feed (mg/L)

Average product (mg/L)

Max product

% Removal

BOD (mg/L) 105.0 <5 13 >95

Suspended Solids (mg/L) 67.0 3.2 8 95

COD (mg/L) 238 104 190 56

TKN (mg/L) 5.2 5.51 11 0

Nitrate (mg/L) 0.2 0.43 1 *

Total P (mg/L) 16.9 16.6 18 0

TOC (mg/L) 43 29 50 33

Conductivity (uS/cm) 324 339 350 0

pH 7.1 6.7 6.8 6

Turbidity (NTU) 46.1 10.7 18 77

Total coliforms (cfu/100mL) >2419.6 0 0 0

E.coli (cfu/100mL) 67 0 0 0

F.Enterococci (cfu/100mL) 850 0 0 0

Calcium (mg/L) 7.4 6.82 7.9 0

Magnesium (mg/L) 1.4 1.5 1.7 0

Sodium (mg/L) 64 67 68 0

Zinc (mg/L) 0.02 0.07 0.14 0

Aluminium (mg/L) 1.5 0.48 1.4 57

*increase observed


The results presented in Table 4 are for the semi-batch Technology C, a biological process with fixed media and chemical disinfection. Results show average feed and product concentrations and the maximum observed value in all product samples. The technology removed a high percentage of BOD and SS and all bacterial sampling found no detectable micro-organisms in the product sample. Full details of the results for the three technologies tested can be found in the Technology Testing Reports (Diaper and Toifl 2006; Diaper et al. 2006; Diaper and Toifl 2007). Statistical analysis of the results requires further discussion.


6 Microbiological testing

During the microbiological testing of each technology, random samples of product water were analysed in house for pH and turbidity to provide a quick check of technology performance. Should these parameters be outside the expected range, further chemical testing is recommended in order to assess whether the technology is operating correctly. Should the chemical analysis prove the technology is not operating correctly, it is recommended that microbiological testing is suspended.

6.1 Bacterial dosing method

Escherichia coli (ATCC 25772) and Enterococcus faecalis (ATCC 19433) preparation and detection The surrogate strain selected for Escherichia coli was ATCC 25922 as it gave the most consistent results and is a recommended strain for use with Colilert tests kits (manufacturer). The surrogate chosen for Faecal Enterococci was Enterococcus faecalis ATCC 19433 as it is also a strain listed by IDEXX Laboratories as proven to work with the Enterolert test.

These IDEXX Laboratories recommended strains are both prescribed as micro-organisms requiring PC2 facilities (Australian Standard 2002). Prior to final selection of bacterial surrogates, a number of other PC1 organisms were trialled which, if successful, would reduce the physical containment requirements for any testing facility for greywater treatment technologies. Strains E Coli K12 and Enterococcus hirae were both trialled but these were found to give poor and inaccurate results with the Colilert and Enterolert test kits. For example, Enterococcus hirae did not fluoresce clearly and determination of positive results was difficult given that the greywater can also produce slight background fluorescence due to components in washing powder and soaps.

The Escherichia coli strain ATCC 25922 was cultured using commercially available BioBalls. Two BioBalls, each containing a known quantity of micro-organisms, were spread onto tryptone soya agar plates (following manufacturer’s instructions) and incubated for 12-24 hours until the colonies had grown to a size where they could be easily removed. All agar plates used during microbiological testing were made according to the instructions supplied with the media. Individual colonies were then scraped from the two plates and spread onto new tryptone soya agar plates. The plates were then incubated for 24 hours prior to harvesting the cells using 5 mL of Ringers™ solution and a sterile loop. The Ringers™ solution and micro-organisms were then transferred aseptically from the plate into a clean sterile container.

The Enterococcus faecalis was cultured in a similar way to the E. Coli, using commercially available BioBalls. Three BioBalls, each containing 30 micro-organisms, were spread onto brain heart infusion agar plates following manufacturer’s instructions and incubated for 12 - 24 hours. Individual colonies were then harvested and spread onto new brain heart infusion agar plates. The agar plates were incubated for approximately 24 hours prior to harvesting the cells, using 5 mL of Ringers™ solution and a sterile loop. The Ringers™ solution and micro-organisms were then transferred aseptically from the plate into a clean sterile container.

A dilution series was prepared for both the E Coli and E faecalis inoculum cultures and Colilert and Enterolert analysis carried out to determine the concentration of each solution (following standard instructions supplied with the tests). Inoculum concentrations of > 106


cfu/100mL were required in order to prove a 7 log removal (minimum detection 100 cfu/100mL).

For dosing a greywater technology, 75 mL each of E. Coli and E. faecalis inocula was mixed with secondary treated effluent and clay, and then added to the greywater feed using a dosing pump (a Prominent gamma/4-W was used in this study). The amount of effluent dosed with each feed was 1% of the volume of greywater fed each time (e.g. 1 L of secondary treated effluent with 100 L of greywater). Feed volumes varied between 100 L and 225 L depending on the feed volume for each technology. Feed samples were taken as a proportion of the total inlet flow from the sample point prior to the technology. The number of feeds for which bacteria were dosed was determined by the results of the tracer study for each technology.

Product samples were taken after processing by the technology and analysed for E Coli and E. faecalis using Colilert and Enterolert Quantitray analysis.

6.2 Virus surrogate dosing method

MS2 and φX174 coliphage selection Previous studies comparing natural and laboratory cultures of bacteriophage in heat treatment of wastewater and sludge state that single phage dosing results cannot be extrapolated to all phages (Mocé-Llivina et al. 2003). Thus, for this study, two bacteriophages were used and their selection was based on size, resistance to certain treatments, isoelectric points and their ease of use. The bacteriophages selected were MS-2 and ΦX174. Although they are a similar size (24 and 27 nm respectively), they have different isoelectric points, ΦX174 pI = 6.6 and MS-2 pI = 3.9 (Dowd et al. 1998). The reason for basing selection on charge rather than size is that, for the greywater treatment technologies currently on the market in Australia, removal at the molecular level will be predominantly influenced by charge rather than size. Both MS-2 and ΦX174 have been used in previous wastewater (Mocé-Llivina et al. 2003; Arraj et al. 2005) and both have well documented detection and enumeration procedures (International Standard Organisation 1995; International Standard Organisation 2000). MS-2 is an f-RNA phage and ΦX174 is a somatic coliphage. The use of other viral surrogates for other technology types will require further investigation. Phage preparation and detection The ΦX174 and MS-2 phages, as well as the WG 49 and E. Coli C hosts, were initially sourced from the culture collection held by the University of NSW. The MS2 bacteriophage was prepared by adding 1 mL of frozen stock of WG 49 (salmonella) host to 100 mL of pre-warmed TYGB. CaCl2/glucose solution (1 mL per 100 mL) and Kanamycin solution (400 µL per 100 mL) were also added to the pre-warmed TYGB for this culture. The culture was placed in the incubator at 37°C for 2-3 hours until it reached mid log phase. Then 1 mL of MS-2 phage (frozen stock) was added and the culture allowed to incubate at 37°C overnight.

The ΦX174 coliphage was prepared by adding 1 mL of frozen stock of E. Coli C to 100 mL of pre-warmed TYGB. CaCl2/glucose solution (1 mL per 100mL) was also added to the pre-warmed TYGB. The culture was placed in the incubator at 37°C for 2-3 hours until it reached mid log phase. Then 1 mL of the ΦX174 coliphage (frozen stock) was added and the culture was further incubated at 37°C overnight.

A dilution series was prepared for each of the phage inocula and a double agar layer assay for MS-2 (International Standard Organisation 1995) and ΦX174 (International Standard


Organisation 2000) was carried out to ensure that the concentration range was correct prior to dosing. The concentrations of each phage had to be at least 106 so that log 7 removal could be proven by any system tested.

Phage dosing was carried out in the same way as the bacteria dosing using 75 mL of each phage mixed with secondary treated effluent and clay, then dosed to the technology via dosing pump for the duration of the feed. The amount of effluent dosed with each feed was 1% of the volume of greywater fed.

Product water samples were assayed for MS2 and ΦX174 phage either in house or by a NATA accredited laboratory. In house analysis used the ISO standard methods for MS-2 (International Standard Organisation 1995) and ΦX174 (International Standard Organisation 2000).

6.3 Protozoa surrogate dosing method

The Clostridium perfringens spores were prepared from frozen stocks obtained from the culture collection held by the University of NSW. These stock solutions were used to prepare spread plates from 200 µL aliquots of stock on ten perfringens agar plates. The plates were incubated anaerobically at 37°C for 3 days. After incubation, the cells were harvested from the plates using 5 mL of Ringers solution and a sterile loop. The mixtures from all the plates were combined and the total volume made up to 150 mL with Milli-Q water. This solution was then incubated aerobically at 37°C for 3 weeks.

Dosing the Clostridium perfringens solution was carried out in the same way as dosing for the bacteria and phage and 75 mL of the Clostridium perfringens solution was mixed with secondary treated effluent and clay and dosed to a technology. Concentrations of spores in the inoculum were in the range 105 to 106 spores/100mL so that 7 log removal could be proven.

Clostridium perfringens was analysed using the method described in AS/NZS 4276.17.1 (2000) (Australian Standard 2000). One litre sample volumes were used as previous work had indicated that the product samples collected required concentration rather than the dilution described in the standard method.

6.4 Helminth surrogate dosing method

The surrogate selected for Helminths were 90 µm fluorescent latex microspheres (Fluoresbrite ® YG microsphere). These were chosen as they are a similar size to Helminths and the fluorescence can be easily detected.

The fluorospheres were added to the secondary effluent (1.2 x 105 beads added) which was then dosed to the system with the synthetic greywater feed in the same way as for the other micro-organisms. The concentration of spheres in the feed was approximately 103 / L. Ten litre product samples were collected for analysis. The samples were analysed by filtration through a 15 cm diameter 2.7 μm filter which was then analysed by visual inspection in UV box, to identify and count any fluorescent points detected.

6.5 Micro-organism dosing results

The results of the micro-organism dosing for the three technologies used in protocol development indicate variability in the log removals observed for the different treatment types (Diaper and Toifl 2006; Diaper et al. 2006; Diaper and Toifl 2007). As greywater formulation


and some methodologies changed throughout the development of the protocol, the direct comparison of technology is not meaningful at this stage.

The results for the fluorospheres were the same for all technologies, with no fluorospheres being detected in any product samples and all technologies providing a log 4 removal. The visual fluorescence detection method used for analysis of samples was problematic as it was difficult to see the fluorospheres in samples where the product water was turbid. Additionally, large volumes of samples needed to be processed in order to determine that no fluorospheres could be detected which was difficult for the turbid samples as the filters became blocked very quickly. Further method calibration would be required in order to validate the procedure if helminth testing were included.

However, it is recommended that a helminth surrogate is NOT incorporated in any future testing protocol because:

• Detection method of surrogate is problematic

• Helminth concentrations in greywater are likely to be very low, if present

• Latex fluorospheres are expensive to provide greater than 4 log removal

• C.perfringens spores are 1-3 μm (Lovins W.A. et al. 2002) and, if size exclusion is the expected removal method, will provide a worst case compared to 90 μm fluorospheres.

Table 5: Example results of micro-organism log removal for Technology C

Microorganism or surrogate

Technology C (Biological + Chemical

disinfection)

E. coli >7

Faecal enterococci >7

Bacteriophage MS-2 1

Coliphage φX174 6

C. perfringens spores 4

Fluorospheres 4


7. Reporting

The reports from the three technologies tested are available on the Smart Water Fund website (www.smartwater.com.au). The report contents are similar for all technologies and incorporate a ‘Protocol and methodology refinements’ section in addition to the description and results from the technology testing. If this testing protocol is to be developed as a national standard, reporting requirements will need to be specified. A suggested report template is provided below. Incorporation of feedback and comment from regulatory authorities is required to progress and finalise these reporting requirements.

• System operation

o Operational description (include schematic)

o System specifications (flows, volumes, capacity, treatment cycle)

o Tracer study

o Outline sampling regime

• Synthetic greywater quality and variability


o Operation (feed cycles, volumes and timing)

o Results

o Comment

• Micro-biological testing

o Bacteria

Operation (feed cycles, volumes and timing)

Results

o Phages


Results

o Clostridium perfringens


Results

• Other technology issues

• Protocol and methodology refinements

• Summary and recommendation.


8. Discussion and recommendations

A robust and repeatable testing protocol for greywater treatment technologies which provides proof of removal of various micro-organisms is required. The methodology proposed in this report bridges the gap between the current prescriptive testing procedures for single house installations and the framework approach recommended for larger scale applications. The protocol is proposed to be applied for each technology (not each installation) and could be combined with a desk-based risk assessment (see Section �9) and field sampling that is less onerous than current requirements.

There are some points that require clarification before the testing protocol outlined in this report is developed to a national standard. Some of these points are recommendations and discussion points while others require additional research to clarify. Some of the recommendations which require discussion that have arisen during the development of the protocol are:

• A helminth surrogate is NOT incorporated in any future testing protocol as surrogate quantification was not accurate and helminth concentrations in greywater are likely to be low.

• Should the chemical analysis prove the technology is not operating correctly, it is recommended that microbiological testing is suspended

• Boron analysis is not included in the feed or product analysis following further investigation of its likely presence in greywater. The concentrations of boron in greywater would need to be confirmed by sending samples to a laboratory that has a very low limit of detection.

• When dosing micro-organism inocula, secondary effluent is not added to the synthetic greywater, due to the potential competition between organisms in the effluent and inocula, which could lower the number of organisms present.

• Treatment technologies based primarily on biological processes are pre-commissioned prior to testing if possible, as start-up times for biological processes were found to be lengthy.

Another recommendation for the testing protocol is that the feed sample point is located closer to the technology (current setup has 4-5 m of pipework and flowmeter prior to technology). Micro-organisms can attach to particulate material and particulate material can settle or adhere to feed pipework and so there may be some removal of micro-organisms in the pipework prior to the technology. Locating the sample point as close to the technology as practically possible will allow these effects to be taken into consideration.

Furthermore, there are some requirements for additional research work which will ensure the protocol is robust, reliable and applicable to a range of technologies. Suggested additional work includes:

• Investigation of the use of other viral surrogates for other technology types which may be based primarily on size exclusion. The surrogate selection for these trials was based on the charge of the surrogates rather than size as this was more relevant for the technologies that we were investigating. However for a membrane based technology, for example, surrogates based on size would be more appropriate.

• Further analysis of the ratio of micro-organism to clay concentrations to ensure a mix of suspended and particulate associated micro-organisms.

• Investigate the use of other tracers, such as Rhodamine B, if there are concerns regarding the effects of sodium chloride on the greywater treatment process.


• Further investigation of Total-N and Total-P ranges is required as the median and averages for the current data analysed, were significantly different from the initial parameter ranges suggested by Smart Water Fund. The original parameter ranges suggested by SWF (1996) showed Total-P levels in greywater are greater than Total-N levels. However, data collected recently from industry sources and some literature suggests that P levels are actually lower than N levels in the greywater. This could be due to changes in detergent formulations with many manufacturers beginning to produce low phosphate detergents to be more environmentally friendly.


9. Future work

The proposed testing protocol outlined in this document does not provide a complete assessment of technology performance and it is recommended that this protocol is combined with a desk-based risk assessment and field testing. In field situations, greywater treatment systems will operate long term and be subject to large variations in greywater quantity and quality and particular householder behaviours. In the laboratory based testing protocol, these issues are not assessed and a structured risk-based assessment is recommended in order to understand the likely impacts of these variations.

Preliminary development of the desk-based risk assessment has been undertaken and a Hazard and Operability (HAZOP) (Kletz 1999) type approach is recommended. This approach requires an understanding of the possible causes of failure of the technology and an assessment of their frequency and consequences. As such, the assessment team should be multi-disciplinary in order to provide expertise in all potential health and environmental risks and include someone with knowledge and expertise in system operation (often the technology manufacturer).

The HAZOP process requires that the system be assessed component by component and utilises keywords, such as ‘NO’, ‘LESS’ and ‘MORE’ to assess the impact of variations in system operation on each component. These keywords are used to identify causes and consequences for each deviation from normal operation. A quantitative scale can then be used to rank the consequences i.e. Major (3), Moderate (2) and Minor (1), and the frequencies of the causes i.e. Almost certain (3), Likely (2) and Unlikely (1) (highlighted in yellow in Table 6). High, medium and low risks can then be identified and appropriate controls can be suggested for high/medium risks if required i.e. frequency x consequence score ≥6 (highlighted in red in Table 6).

Table 6: Example of HAZOP assessment method

Technology: System X Unit operation: Feed tank Guideword: None

Deviation Potential causes

Consequences Risk Controls

No flow into system for extended period

Normal operation i.e. Holidays (3)

Nuisance odours as untreated greywater stored in tank (2)

(6) Redesign system to allow complete emptying of tanks

Blockage in collection pipework (1)

No drainage of greywater from supply point (2)

(2) None

No level sensing Fault with level sensor (1)

Incorrect installation (2)

Tank overflow (2)

Automatic system start up not initiated (3)

(2)

(6)

None

Overflow design for maximum flow

This assessment method is not yet fully developed for specific application to greywater technologies and further definition of keywords and deviations is required to ensure the


assessment is comprehensive. Comment and discussion from regulatory authorities is required before further development of this process occurs.

In addition to the laboratory based testing and desk-based assessment, further development of necessary field monitoring and analysis is required in order to ensure the performance of the system is maintained in the longer term.


Appendix 1 – Synthetic greywater components

Market share of products used

Extracts from the IbisWorld report Soap & Other Detergent Manufacturing in Australia (28 July, 2005) suggest that Omo, Colgate, Palmolive are representative brands (see below). Since the time of development of the synthetic greywater recipe more detailed market share information has been obtained and this information could be used to update the formulation.

Colgate-Palmolive (extract from IbisWorld 2005)

“In relation to this industry, the operations of Colgate Palmolive Australia involve the manufacture and distribution of household cleaning, personal care products, and skincare. It is probably best known for its toothpastes, detergents and soaps. Well known brand names include Ajax, Cashmere Bouquet, Cold Power, Colgate, Cuddly, Dynamo, Fab, Total, Nifti, Palmolive, Sard and Spree. Also included is “Soft as Soap” brand which was acquired from Reckitt Benckiser in 2000-01 as well as the Fluffy & Castle brands acquired from Campbell Brothers in October 2004. In 1999, Colgate Palmolive was the market leader in the body wash market (24 percent market share) and held second place in the general hard surface cleaner market (17 percent market share) and the laundry fabric softener market (25 percent). It dominated the toothpaste segment with a 60 percent market share. During the year, the company spent roughly $15 to $20 million in total on advertising for its various products, putting it in the top 50 spenders on media expenditure. A study by AC Nielsen found that Colgate-Palmolive was the overall market leader in the bar and liquid soap segment in 2000 with 36.4 percent of the market, followed by Soft as Soap with 25.8 percent.”

Unilever Australia (extract from IbisWorld 2005)

“In relation to this industry, Unilever Australia is probably best known for its soaps, laundry powders and liquids and cleaners. Following a series of divestments, remaining key brands include Lux, Dove, Domestos, Jif, Handy Andy, Omo, Surf and Drive. Unilever is the market leader in a number of major market segments in this industry, including heavy-duty cleaners, floor cleaners and laundry powders. According to AC Nielsen figures released in mid 2002, Unilever was the leading manufacturer within the men's toiletries and soap segment commanding a 38 percent share of the $129 million market with its Rexona brand. It was also thought to have a 32 percent share of the $585 million laundry market.”

Review of chemicals in household products used for synthetic greywater Laundry powder Omo High Performance concentrate 1kg, 5way cleaning action by Unilever (Customer info: 1800 225 508, www.omocareline.com.au )

Ingredients as per package:

• Anionic and non-ionic surfactants (Commonly used are alcohol ethoxylates and alkyl phenol ethoxylates)

• Optical brightener/fluorescer • Enzyme (commonly used is proteinase) • Alkalis • Sodium polyphosphate • Zeolite (synthetic ion-exchanging zeolites are commonly used) • Polymer


• Perfume • Colour.

Ingredients as per Unilever Australasia MSDS Omo Concentrate powder

• Sodium carbonate (CAS-No 497-19-8) 30-60% • Anionic surfactant 10-30% • Nonionic surfactants <10% • Sodium silicate (CAS-No 1344-09-8) <10% • Fluorescer <10% • Protease enzymes <10% • Other ingredients determined not to be hazardous to 100% • pH approx.10 -11 (1% @20°C).

Palmolive Soft Wash Milk and Honey 500 mL, made in Thailand (Customer info: 1800 802 307)


• Water • Sodium Laureth sulphate • Cocamidopropylbetaine • Cocaminde DEA • Lauryl glucoside • Polyquaternium 7 • Fragrance • Glycol distearate • Laureth-4 • Sodium chloride • Sodium sulphate • Citric acid • Poloxamer 124 • Sodium styrene/acrylates copolymer • DMDM Hydantoin • Methylchloroisothiazolinone • Methylisothiazolinone • Tetrasodium EDTA • Honey • Dry milk powder • Ci 19140 • Ci 16035.

Anti-perspirant Mum Dry Active, 24h by Procter and Gamble (Customer info: 1800 226 524)

Active ingredients as per package:

• Aluminium chlorohydrate (22%w/w)

Other common ingredients in anti-perspirants

• Binders • pH agents.


Sunscreen UV Triplegard 75 mL by Boots Healthcare (New Zealand) (Customer info: 1800 226 766)


• Octyl methoxycinnamate 80 mg/mL • Oxybenzone 30 mg/mL • Butyl methoxydibenzolmethane 40 mg/L • Phenoxyethanol 1.6 mg/mL • Methyldibromo glutaronitrile 400 μg/L.

Toothpaste Colgate Maximum Cavity Protection, regular flavour, 140 g by Colgate (Customer info: Colgate Oral Care 1800 802 307)


• Sodium monofluorophosphate 0.76% w/w.

Other common ingredients in toothpaste:

• Abrasives: used to provide cleaning power, common compounds used are calcium carbonate, silica, calcium phosphate, and alumina.

• Detergents: used to create the foaming action and keep it from dribbling. The most common detergent is sodium lauryl sulphate.

• Humectants: to provide texture and retain moisture. Common humectants are Glycerin, sorbitol, and water. Xylitol is a superior humectant but not commonly used.

• Thickeners: Common thickeners are Carrageenan, cellulose gum and xanthan gum. • Preservatives: used to prevent growth of microorganisms in toothpaste. Common

examples are sodium benzoate, methyl paraben, triclosan and ethyl paraben. Common preservatives include sodium benzoate, methyl paraben, and ethyl paraben.

• Flavouring agents: Used to improve the taste of toothpaste. Most toothpaste sweeteners are artificial and contribute very little to cavity formation. A common sweetener used is Saccharin.

• Colouring agents: used to improve the appearance of toothpaste. Artificial dyes are used to colour red, green, and blue toothpastes. Titanium dioxide is used to make some toothpastes white.

• Tartar control: toothpaste that are designed for tartar control commonly contain pyrophosphate.

Sunscreen UV Triplegard 75 mL by Boots Healthcare (New Zealand) (Customer info: 1800

226 766)


• Octyl methoxycinnamate 80 mg/mL • Oxybenzone 30 mg/mL • Butyl methoxydibenzolmethane 40 mg/L • Phenoxyethanol 1.6 mg/mL • Methyldibromo glutaronitrile 400 μg/L. Dove Protecting Moisturising Lotion


• Octyl methoxycinnamate (5.5%) • Butyl methoxydibenzoylmethane (2.0%)


• Octyl salicylate (3.0%) • Phenylbenzimidazol sulfonic acid (2.0%). Also contains: • Methylparaben • Propylparaben • Phenoxyethanol • Iodopropynyl butylcarbamate • Fragrance.


Appendix 2 – Estimation of amount of products used

Average volume of greywater produced is 230 l/household/day*

43%* or 100 l/household/day greywater from washing machine

57%* or 130 l/household/day greywater from bathroom *Melbourne Water Map, Yarra Valley Water 240 kL/hh/year, 20% bathroom, 15% laundry

Shampoo and laundry detergent 30* g soap/shampoo/conditioner per shower/bath and 4 showers per day

9* g soap per handwash and 5 handwashes per day *Shampoo and soap account for all products used in shower/bath and sink except toothpaste

Total of 165 g for 130 L of greywater

1 scoop laundry detergent 88 g

88 g per laundry wash

Average wash rate 0.4 washes/household per day

0.4 x 88 g/household per day = 34.5 g for 100 L laundry greywater

230 L daily contains 34.5g laundry detergent and 120g shampoo/soap/conditioner

100 L requires 15 g laundry detergent and 72g shampoo Deodorant, sunscreen and toothpaste Estimated amounts used per household per day

1.1 g deodorant for 130 litres bathroom greywater

3.5 g sunscreen for 130 litres bathroom greywater

7.5 g toothpaste for 130 litres bathroom greywater

230 L daily contains 1.1 g deodorant, 3.5 g sunscreen and 7.5 g toothpaste

100 L requires 0.5 g deodorant, 1.5 g sunscreen, 3.25 g toothpaste


Appendix 3 – Properties of Unimin clay

The particle size distribution and chemical and physical properties of the Unimin clay used in the synthetic greywater are provided below.


Appendix 4 – Real greywater quality

Greywater quality data was collected and collated from literature values or data from greywater technology testing programs run by system manufacturers or independent testing organisations (e.g. Ecowise). As expected, there was a large variability in the analysed parameters as the greywater quality data came from a variety of different dwelling types (a youth hostel, a caravan park, single residential houses and multi-residential dwellings) and sources (laundry only, bathroom only or laundry and bathroom combined). In addition, the householder behaviour varied between the different sites, with some householders being very environmentally aware (minimising water and product use and using products with environmental labelling), whilst others were not. In addition, not all raw data was available for analysis and so there was a mix of spot samples, averages or mean values and median data. This variability in the type and sources of data collected did not merit detailed statistical analysis of the data and so a simple analysis was used, in which median and average values were calculated for all the data. The values were then used to assess whether parameter ranges needed to be widened or reduced or the whether the median of range should be increased or reduced.

Table 7: Synthetic greywater parameter ranges compared to Australian greywater data

Parameter Original range

Updated range (mg/L unless

otherwise stated)

Average of collected data

Median of collected data

Suspended solids (mg/L)

60 - 80 60 - 80 76 45.5

BOD (mg/L) 150 - 200 130 - 180 172 109 Turbidity (NTU) 60 – 80 50 – 70 52 43.6 Sodium (mg/L) 80 – 130 50 – 90 96 73

Total phosphorous –

P (mg/L)

10 – 20 10 – 20 5.9 3.12

Total Kjeldahl nitrogen – N

(mg/L)

3.0 – 5.0 3.0 – 5.0 11.1 11.6

Conductivity (μS/cm)

450 - 550 300 - 400 361 290


103 – 104 103 – 104 68200 23500

Faecal coliforms (cfu/100mL)

201 202


Table 8: Australian greywater quality data

Comments BOD SS TKN Total - N Turbidity EC TP Na TC FC

Healthy home (Gardner and Millar, 2003)

Median 97 48 6.6 0.7 180000 100

Caravan park (Flapper et al., 2005)

Max and min only

Lavendar Park (pers comm. Ecowise)

Spot sample 130 43 3.5 3.5 82 290 0.14 >2000

Bath and shower (pers comm. Ecowise)

Average 5 to 10 samples

39 33.8 144

Laundry (pers comm. Ecowise)


39 43.6 332

Laundry and bathroom (pers comm. Ecowise)


34 33.8 189

YHA 1 (pers comm. Ecowise)

Median 52.5 79.5 14 15 2.75 202

YHA 2 (pers comm. Ecowise)

Median 180 73.5 9.1 9.1 3.5

Westwyck (CRC Report, 200?)

Average 385 1.5 38 988 300

Inkerman shower and hand basin (CRC Report, 200?)

Average 4.25 51.4 170 1.35

Landloch Pty Ltd 2005 Laundry only 787 100.6 11.9 1037 21.5 177.9 <1 Christova Boal et al 1996 Max and min

only

Jeppesen 1996 Sullage 159 113 11.6 100 601 8.1 73 Eight person household (pers comm. Ecowise)

Median 210 335 12.6

Bio-flow Maidstone Average 57 25 5.53 5.57 10.13 Bio-flow Williamstown Average 68.5 21.5 15.53 15.53 10.2

Bio-flow Mt Evelyn Average 109.25 90 21.67 21.67 10.37 Highett House (Tunaley,

2004) Median 38 23 6.6 21.5 103.5 0.28 23500

AVERAGE 172 76 11.1 10.3 52 361 5.9 96 68163 201 MEDIAN 109.25 45.5 11.6 9.1 43.6 290 3.125 73 23500 202


Appendix 5 – Modifications to synthetic greywater formulations

Ingredient Product used Formulation 1 Amount in 100L (g) Unless otherwise stated

Formulation 2 Amount in 100L (g) Unless otherwise stated

Formulation 3 Amount in 100L (g) Unless otherwise stated

Sunscreen UV triplegaurd 1.5 1.5 1.5

Toothpaste Colgate 3.25 3.25 3.25

Deoderant Mum 0.5 1.0 1.0

Na2SO4 Analytical Grade 5 3.5 3.5

Unimin Clay Industrial Grade 5 5.0 5.0

Urine 1 ml ^ ^

Vegetable Oil Coles Own brand 0.7 0.7 0.7

Shampoo Palmolive 72 72 72

Laundry Detergent

Omo High Performance/

Omomatic concentrate

15 15 15

Antifoam Silfoam SEA39 1.5 As required ^

Secondary Effluent Carrum STP 1L 1 L 1 L

Boric Acid Analytical grade ^ 0.14 0.14

Urea Analytical Grade ^ 0.5 0.5

NAHCO3 Analytical Grade ^ 2.5 2.5

Na2PO4 Analytical grade ^ ^ 3.9

^ = Ingredient not included


Appendix 6 – Changes in parameter ranges for large scale batches using different synthetic greywater formulations

Parameter Original range

(Jeppesen 1996)

Updated range

Appendix 3 (mg/L unless

otherwise stated)

Results from large scale batches -

Formulation 1


Formulation 2


Formulation 3

Suspended solids 60 - 80 60 - 80 51.4 ± 17.9 70.3 ± 14 67 ± 47.1 BOD 150 - 200 130 - 180 84.2 ± 28.2 125 ± 11 105 ± 13.3

Temperature 20˚ - 30˚C 25˚ - 35˚C pH 6.5 – 8.0 6.5 – 8.0 6.9 ± 0.2 8.2 ± 0.7 7.1 ± 0.1

Turbidity 60 – 80 NTU

50 – 70 NTU 32.8 ± 17.7 27.3 ± 5.2 46.1 ± 25.4

Boron 0.1 – 0.5 0.1 – 0.5 0.8 ± 0 <1.5 < 2.0

Sodium 80 – 130 50 – 90 57.7 ± 5 56.4 ± 1.2 64.5 ± 1.1 Calcium - - 6.7 ± 0.6 7.4 ± 0.4 7.4 ± 0.3

Magnesium - - 1.3 ± 0.1 1.5 ± 0.04 1.4 ± 0.1 Aluminium - 1.5 ± 1.0

Zinc 0.1 – 0.5 0.1 – 0.5 0.08 ± 0.01 <0.01 0.02 ± 0 Total phosphorous-

P 10 – 20 10 – 20 9.7 ± 0.6 9.1 ± 0.2 16.9 ± 1.5

Total Kjeldahl nitrogen-N

3.0 – 5.0 3.0 – 5.0 4.5 ± 1.1 5.4 ± 0.4 5.2 ± 0.1

Nitrate <0.2 0.2 Nitrite 0.014 ± 0.005 0.007 ± 0.004

Conductivity (μS/cm)

450 - 550 300 - 400 298 ± 29.5 281 ± 7.4 324 ± 12.6

COD 250 - 400 250 - 400 171.1 ± 35.5 224 ± 15 238 ± 11.4 TOC 50 - 150 50 - 150 35.1 ± 5.9 48.5 ± 12 43 ± 6.4


103 – 104 103 – 104 >2419.6 >2419.6

E.coli (cfu/100mL) 101 - 102 102 – 103 83 ± 113 67 ± 100 F.Enterococci (cfu/100mL)

7.8 ± 5.1 850 ± 1111

Highlighted cells show out of range parameters


References

Arraj, A., J. Bohatier, et al. (2005). "Comparison of bacteriophage and enteric virus removal in pilot scale activated sludge plants." Journal of Applied Microbiology 98: 516-524.

Australian Standard (2000). Water Microbiology. Australian Standard (2002). Safety in Laboratories Part 3: Microbiological Aspects and

Containment Facilities. Birks, R. and S. Hills (2007). "Characterisation of Indicator Organisms and Pathogens in

Domestic Greywater for Recycling." Environmental Monitoring and Assessment 129(1-3): 61-69.

Birks R., Colbourne J., et al. (2004). "Microbiological water quality in a large in-builidng water recycling facility." Water Science and Technology 50(2): 165-172.

Brandes, M. (1978). "Characteristics of effluents from gray and black water septic tanks." Journal of Water Pollution Control Federation. Vol. 50, no. 11, pp. 2547-2559. 1978. 50(11): 2547-2559.

Brown R. and Palmer A. (2002). Water Reclamation Standard: Laboratory testing of systems using greywater, BSRIA, UK.

Casanova, L. M., V. Little, et al. (2001). "A survey of the microbial quality of recycled household graywater." Journal of the American Water Resources Association [J. Am. Water Resour. Assoc.]. Vol. 37, no. 5, pp. 1313-1320. Oct 2001. 37(5): 1313-1320.

Diaper, C. and M. Toifl (2006). Greywater technology testing: Test 3 Everwater grey2blue. CSIRO Water for a Healthy Country Report, Smart Water Fund.

Diaper, C. and M. Toifl (2007). Greywater Technology testing: Test 4 New Water Aqua Reviva. CSIRO Water for a Healthy Country Client Report, Smart Water Fund.

Diaper, C., M. Toifl, et al. (2006). Greywater Technology Testing: Test 2 Pontos Aquacycle 900. CSIRO Water for a Healthy Country Report, Smart Water Fund.

Diaper C. and Toifl M. (2006). Greywater technology testing: Test 3 Everwater grey2blue. CSIRO Water for a Healthy Country Report, Smart Water Fund.

Diaper C. and Toifl M. (2007). Greywater Technology testing: Test 4 New Water Aqua Reviva. CSIRO Water for a Healthy Country Client Report, Smart Water Fund.

Diaper C., Toifl M., et al. (2006). Greywater Technology Testing: Test 2 Pontos Aquacycle 900. CSIRO Water for a Healthy Country Report, Smart Water Fund.

Dowd S.E., Pillai S.D., et al. (1998). "Delineating the specific influence of virus isoelectric point on virus adsorption and transport through sandy soils." Applied and Environmental Microbiology 64(2): 405-410.

Dowd, S. E., S. D. Pillai, et al. (1998). "Delineating the specific influence of virus isoelectric point on virus adsorption and transport through sandy soils." Applied and Environmental Microbiology 64(2): 405-410.

Environment Protection and Heritage Council, Natural Resource Management Ministerial Council, et al. (2006). Australian Guidelines for Water Recycling: Managing Health and Environmental Risks (Phase 1). National Water Quality Management Strategy.

Environmental Protection Authority Victoria (1991). Guidelines for wastewater irrigation. Melbourne.

Eriksson, E., K. Auffarth, et al. (2002). "Characteristics of grey wastewater." Urban Water 4: 85-104.

Friedler, E. (2004). "Quality of Individual Domestic Greywater Streams and its Implication for On-Site Treatment and Reuse Possibilities." Environmental Technology 25: 997-1008.

IbisWorld (2005). Soap and other detergent manufacturing in Australia. International Standard Organisation (1995). Water quality - Detection and enumeration of

bacteriophages - Part 1: Enumeration of F-specific RNA bacteriophages, ISO.


International Standard Organisation (2000). Water Quality - Detection and enumeration of

bacteriophages - Part 2 Enumeration of somatic coliphages, International Standard Organisation.

Jefferson, B., A. Palmer, et al. (2004). "Greywater characterisation and its impact on the selection and operation of technologies for urban reuse." Water Science and Technology 50(2): 157-164.

Jeppesen, B. (1996). Model Guidelines for domestic greywater reuse for Australia. Report No. 107, Urban Water Research Association of Australia.

Kletz, T. (1999). Hazop and Hazan, Taylor & Francis. Lovins W.A., Taylor J.S., et al. (2002). "Micro-organism removal by membrane systems."

Environmental Engineering Science 19(6): 453-465. Mocé-Llivina, L., M. Muniesa, et al. (2003). "Survival of Bacterial Indicator Species and

Bacteriophages after Thermal Treatment of Sludge and Sewage " Applied and Environmental Microbiology 69(3): 1452-1456.

New South Wales Department of Energy Utilities and Sustainability (2007). NSW Guidelines for: Greywater reuse in sewered, single household residential premises. Sydney.

New South Wales Department of Water and Energy (2007). Interim NSW Guidelines for Management of private recycled water schemes. Sydney.

New South Wales Government (2006). Metropolitan Water Plan: 38-39. New South Wales Health Department (2005). Domestic greywater treatment systems

accreditation guidelines. New South Water Health (2005). Greywater and sewage recycling in multi dwellings and

commercial premises - Interim Guidance. Sydney, NSW. Ottoson, J. and T. A. Stenstroem (2003). "Faecal contamination of greywater and associated

microbial risks." Water Research 37(3): 645-655. Ottoson, J. and T. A. Stenstroem (2003). "Growth and reduction of microorganisms in

sediments collected from a greywater treatment system." Letters in Applied Microbiology 36: 168-172.

Rose, J. B., G. S. Sun, et al. (1991). "Microbial quality and persistence of enteric pathogens in graywater from various household sources." Water Research 25(1): 37-42.

Siegrist R.L., Witt M., et al. (1976). "Characteristics of rural household wastewater." Journal of the Environmental Engineering Division EE3: 533-548.

Victorian Government Department of Sustainability and Environment (2004). Our Water Our Future Action Plan. Melbourne.

Walpole, R. and K. J. Hartley, Eds. (1993). Characteristics of australian wastewaters. Australia.

Walter, R., C. Baumgartiger, et al. (1995). "Viruses in river waters and sediments in Austria." Water Science and Technology 31(5-6): 395-401.

Winward, G. P., L. M. Avery, et al. (2007). "A study of the microbial qulaity of grey water and an evaluation of treatment technologies for reuse." Ecological Engineering 32(2): 187-197.

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