Course 2 Unit 1Part A B C D

1

Teacher

Mariska Ronteltapm.ronteltap@unesco-ihe.org

Treatment aspects for urine, faeces and greywater

Content:Part A – Basics and overviewPart B – General treatment aspects for urinePart C – General treatment aspects for faeces

Part D – General treatment aspects for greywater (in separate file)

Course 2 Unit 1

Course 2 Unit 1

Part A: Basics and overview

Course 2 Unit 1

Where does Course 2 fit in the overall sanitation system scheme?

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Course 2, Units 1-7

Where does C2 Unit 1 fit in the overall sanitation system scheme?

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Another way of looking at it: Course 2 in the scheme of nutrient recycling

Sanitised urine and faeces (“ecosan products”)

Human excreta

Crop & Harvest

Consumption followed by urination / defecation

Focus of Course 2

Sanitisation steps

Apply as fertiliser and soil conditioner

Aims of treatment of urine, faeces and greywater

The main aims of treatment are:

1. Sanitisation (= pathogen kill) protect public health

2. Groundwater protection indirectly, this also protects public health (see Course 1 Unit 3 Part A)

3. For ecosan: enable safe reuse

There can also be secondary aims, which may vary, but

they need to get lower priority (see later in this presentation).

Pathogen = disease-causing micro-organism (a biological agent that causes disease or illness to its host)

Enteric or enteral = pertaining to the intestine– Intestine = the portion of the alimentary canal extending from the stomach to the anus

Source: www.wikipedia.org

What is a pathogen and what is enteric? Course 2 Unit 1

Definition of terms: disinfection, sanitisation, sterilisation

Term Degree of pathogen destruction

Examples of technical processes

Disinfection Partial Tertiary treatment step in conventional wastewater treatment

Sanitisation / hygenisation

Most or all Primary or secondary treatment step for urine, faeces or greywater

Sterilisation All Medical routines; not practical for excreta management

Need to weigh up remaining risk versus cost of treatment The allowable risk depends on reuse application and other barriers that are in place ( we will talk about the Multiple Barrier Approach in C3U1)

There are four groups of pathogens potentially present in human excreta

Pathogen group

Pathogen Disease caused by pathogen

Bacteria Aeromonas spp.

Escherichia coli

Salmonella typhi

Salmonella spp.

Shigella. spp.

Vibrio cholerae

Enteritis *

Enteritis

Typhoid

Salmonellosis

Shigellosis

Cholera

Viruses Hepatitis A virus

Rotavirus

Hepatitis

Enteritis

Parasitic protozoa

Giardia intestinalis

Cryoptosporidium parvum

Giardiasis

Cryptosporidiosis

Helminths Ascaris lumbricoides (roundworm)

Taenia solium (tapeworm)

Ancylostoma duedenale (hookworm)

Schistosoma spp.

Ascariasis

Taeniasis

Itch, rash, cough, anaemia, protein deficiency

Schistosomiasis, bilharzia

Source: WHO (2006), p.33

Course 2 Unit 1

Factors that influence pathogen die-off

After excretion, the concentration of enteric pathogens usually declines with time by death or loss of infectivity

Bacteria may multiply under favourable environmental conditions

Protozoa and viruses are unable to grow in the environment outside the host, hence their numbers will always decrease

Time and prevailing conditions are the overall features affecting survival of pathogens in the environment

Giardia lambliaOne of the more common

parasitic organisms is Giardia lamblia. This parasite grows in

the upper GI tract and produces greasy, smelly

diarrhea.(microbiology.mtsinai.on.ca/

pig/helminth11.shtml )Source: Schönning and Stenström (2004)

Disinfection methods used in water and wastewater treatment (for reference)

Chemical agents– Chlorine and its compounds– Ozone– Various acids (to achieve pH < 3) – Various alkalines (to achieve pH > 11)– Urea

Physical agents– Time*– Heat*– Dryness*– Light

• Sunlight*• UV lamps

All of these could be used as part of ecosan concepts, but the ones highlighted with * are most commonly used (low-cost applications)

Course 2 Unit 1

Part B: General treatment aspects for urine

Note: For characteristics of urine see Course 1 Unit 2

Urine storage tank, Hengelo, the Netherlands (July 2007)

Course 2 Unit 1

Primary and secondary aims for urine treatment

Primary aim:

1. To kill viruses and pathogens

2. To enable safe reuse (for urine, that means: no (ground)water pollution; no danger for the workers; rather no ammonia evaporation)

In several countries people know very well the value of urine as a fertiliser. Here we see an example from India where you get a rupee if you use their toilet..

Secondary aims:

1. To obtain monetary value from (components in) urine in the form of fertiliser, energy, an others

2. To reduce the load to the WWTP or receiving water bodies

The easiest and most common treatment method for sanitisation of urine is by storage

Pathogen kill by storage of urine is due to:

1. Rapid conversion of urea to ammonia which increases the pH

2. Increased ammonia concentration together with the increase in pH have a sanitising effect

3. Time by itself also kills many pathogens (being away from a host)

Urine storage tank in basement of apartment block Gebers in Stockholm, Sweden (Aug. 2007) – with Anselme Vodounhessi from CREPA, Burkina Faso

Which pathogens are present in urine?

By far the most pathogens in excreta are in the faecal part. In urine also some were found: Schistosoma haematobium, Salmonella typhi, Salmonella paratyphi,

Leptospira interrogans Mycobacterium tuberculosis in urine of humans with renal TB

infection

Other pathogens come from faecal contamination – you can imagine that some of the faeces ends up in the urine opening: an average of 9.1 mg faeces/L urine was measured. Vinnerås et al., 2008)

Dilution, temperature or pH?

Storage was always thought to be the best treatment. Bjorn Vinneras et al (2008) looked into other aspects: dilution rate, temperature and ammonia concentration. They found that dilution rate is an important factor regarding the reduction in pathogenic microorganisms in urine:

At all temperatures: lower than 40 mM NH3 inactivation is slow (NH3 is regulated by total ammonia concentration,

temperature and pH)- At temperatures < 20°C: restrictions on the use of urine as a

fertiliser on food crops, as ascaris and viruses are reduced at a very slow rate.

Dilution, temperature or pH?

At 34 ° C fast inactivation of all organisms was observed, even at 1:3 dilution of urine.

If all ammonia is out, pathogens survive even at higher temperature!

How long should urine be stored for?

Centralised systems (urine from many households is mixed together)– Recommended storage time is 1-6 months, depending on

temperature and type of crop to be fertilised (see next slide)– 1 month storage sufficient if T > 20°C and crop is not to be

eaten raw Individual one-family system:

– No storage is needed (see also slide after next) Note: Urine in the storage tank should not be diluted (concentrated

urine provides a harsher environment for micoorganisms and hence more effective pathogen kill)

Source: WHO (2006)

Recommended guidelines for storage times of urine mixture

Storage temperature

Storage time Possible pathogens in the urine mixture after storage

Recommended crops

4°C > 1 month Viruses, protozoa Food and fodder crops that are to be processed

4°C > 6 months Viruses Food crops that are to be processed, fodder crops

20°C > 1 month Viruses Food crops that are to be processed, fodder crops

20°C > 6 month Probably none All crops

Urine mixture: urine which may be mixed with water

Source: Schönning and Stenström (2004) and also adopted in WHO (2006)

Course 2 Unit 1

New insights: shorter is fine, if undiluted and warm

For safe unrestricted reuse of urine, it needs to contain 40 mM or more of uncharged ammonia and be stored above 20 °C. Then the required storage time according to WHO guidelines could probably be shortened (Vinnerås et al., 2008)

21

Is urine sanitisation (by storage) really necessary?

YES, because: In a healthy individual, urine in

the bladder is sterile, but different types of bacteria are picked up in the urinary tract

Persons infected with Schistosoma haematobium excrete the eggs in urine. The eggs hatch in the freshwater environment

Urine could be contaminated by faeces if users of UD toilet are not careful

Source: Schönning and Stenström (2004)

NO, because: Urine contains few disease-

causing organisms Urine-oral transmission is

much less likely than faecal –oral transmission of disease (WHO, 2006, page 34)

A multiple barrier approach is used for reuse of urine (see also Course 3 Unit 1)

You need to weigh this up on a case by case basis

Advantages and disadvantages of storing urine compared to using it “fresh”

Advantages: Simple and effective method for pathogen kill Allows waiting for the right time for application to soils in

relationship to planting and harvesting times (See Course 3 “Safe reuse of ecosan products in agriculture”)

Disadvantages: Cost of urine storage tank Some loss of nitrogen possible during storage (via ammonia

gas)

More information on practical aspects of urine storage is provided in Course 2 Unit 3 “Storage and transport logistics”

Possible secondary treatment aims and treatment methods specific for urine (most of them require “high-tech” treatment options)

• Nitrogen recovery (to allow reuse of N in fertiliser)• Nitrogen removal (to reduce nitrogen load to WWTP)

– Biological process: nitrification and denitrification (convert ammonia to nitrate and then nitrogen gas) or ANAMMOX process

• Removal of micro-pollutants and pharmaceutical residues (to make urine even safer for reuse in agriculture)– Electrodialysis– Nanofiltration– Ozonation and advanced oxidation

Some of these treatment aims play a role in projects in the Netherlands and Switzerland (see next couple of slides). Struvite precipitation also takes place in the developing world, see the project in Nepal (STUN)

Example for high-tech treatment method for urine: vacuum evaporation

Advantages:– Allows volume reduction

Technical problems:– High energy demand– Pre-treatment necessary

to lower pH– Distillate is high in

ammonia

Source: Ecosanres Discussion Forum, Felix Tettenborn, TU Hamburg-Harburg (29 May 2006 and an update with further information on 22 February 2007)

Vacuum evaporation (lab scale). Photo: Felix Tettenborn

Course 2 Unit 1

Example for high-tech treatment method for urine: struvite precipitation

By adding magnesium, a crystal precipitates with phosphate called struvite: MgNH4PO4

Advantages:

- Struvite is a slow-release fertilizer. By separating this from the liquid phase, we have a strong reduction of volume- Easy and rapid- The effluent can be used for irrigation

For a pilot scale example, check the link here to the right

Course 2 Unit 1

Nepal: Pee proudly for healthy vegetables

(this is a link to the internet)

Example for High-tech treatment method for nitrogen removal from urine

Nitrification (biologial process) to convert ammonia to nitrate

Pilot plant at Hengelo (project of the

Waterboard Regge en Dinkel in Almelo, the Netherlands)

Pilot-scale nitrification reactor with attached growth (July 2007): treating 1 m3 of urine per week

Course 2 Unit 1

Continued from previous slideLeft bottle: Stored urine before treatmentRight bottle: Urine after treatment (ammonia converted to nitrate)

Here you see Elisabeth doing the smell test: it does not smell (ammonia is gone)Some participants on this field trip did not dare to do the smell test...

Further reading about high-tech treatment methods of urine

Maurer, M., Pronk, W. Larsen, T.A. (2006) Review: Treatment processes for source-separated urine, Water Research, 40, p. 3151 – 3166 *

Pronk, W., Zuleeg, S., Lienert, J., Escher, B., Koller, M., Berner, A., Koch, G., Boller, M. (2007) Pilot experiments with electrodialysis and ozonation for the production of a fertilizer from urine, Advanced Sanitation Conference, Aachen, Germany, 12 – 13 March *

* Also provided on the I-LE under Extra Materials for this course unit

What are alternative options if no agricultural reuse of urine is possible?

Infiltrate into ground (e.g. in Durban rural areas, South Africa) – check potential for nitrate pollution of groundwater

Add to composting operations (but loss of ammonia)

Discharge to sewer and wastewater treatment plant

If amounts are small and climate is suitable: evaporation

Other more “exotic” uses of urine (other than use as a fertiliser)

As an insecticide– See Ecosanres Discussion Forum on 11 June 2007 and earlier postings;

note: when plants have a good  nutritional balance, they resist the attak of pathogens and insects – so reported insecticidal properties of urine may be a secondary effect (?) – more research is needed

As a medicine– Some people strongly believe that drinking urine is good for you! (e.g.

http://www.rotten.com/library/medicine/bodily-functions/pissing/drinking-pee/)

– As a disinfectant for wounds (smearing wounds and sores)– To improve your skin

To produce the human fertility hormone hCG– Can be extracted from urine of pregnant women and then given to other

women for fertility treatment (see my entry on Ecosanres Discussion Forum on 3 July 2007)

To use for odour control in sewers (after conversion of ammonia to nitrate)– This is being tested by the Waterboard Regge en Dinkel in the

Netherlands (in 2007)

Can you give examples of such “exotic” uses for urine?

Course 2 Unit 1

Part C: General treatment aspects for faeces

Note: For characteristics of faeces, see Course 1 Unit 2

Course 2 Unit 1

Reminder: main treatment aims for faeces

Sanitisation (= pathogen kill) protect public health ! Enable safe reuse (desirable)

Possible secondary treatment aims specific for faeces

– Volume reduction (remember faeces are about 80% water at excretion)

– Odour reduction– Prevention of groundwater pollution by pathogens in fresh

faeces– Change appearance, so that it no longer looks like faeces

Sanitising faeces: What kills pathogens in faeces?

Factor Mechanism Technology examples

Storage time * A longer storage time kills pathogens Storage *

Temperature At temperatures of 55-65°C all types of pathogens (except bacterial spores) die within hours

Composting (thermophilic); solar drying toilets

pH Highly acidic or alkaline conditions will have an inactivating effect (adding sawdust, ash or lime increases pH)

Alkali treatment

Ammonia Pathogens in excreta can be inactivated by the addition of ammonia

Addition of urease

Dryness / moisture *

Pathogens die off with lack of moisture (addition of drying agents, e.g. sand, ash)

Desiccation *

Solar radiation / UV light

Survival time of pathogens on crop and soil surface is reduced by UV radiation

Spreading faecal sludge in the open

Source: Winblad and Simpson-Hebert (2004)

* Applied in UDD toilets (UDD = urine-diversion dehydration)

Adding ash to faeces in UDD toilets: a common “pre-treatment” step

Promotes pathogen die-off through elevated pH of the ash Reduces smell Covers material

– reduces fly breeding– improves aesthetical conditions

Decreases moisture content

How much should be added? – One cup, or 200 – 500 mL ash; enough to cover faeces (WHO

(2006), p. 69)What else can be used?

– Lime, sand, soil, saw dust, leaves, compost or nothing– Note: we are not adding anything to the UDD toilet in the UNESCO-

IHE building because it has a fan (see presentation in Course 1 Unit 3 Assigned Reading)

Course 2 Unit 1

2 levels of excreta treatment: primary, secondary

Urine;faeces

Sanitised urine;sanitised faeces

Sanitised urine;partially sanitised faeces

PRIMARY TREATMENT Treatment integrated into individual toilet Usually sufficient when households can

reuse their own products

Examples: Storage and drying in the toilet (double-pit

collection is preferred) Alkaline treatment (addition of ash and lime;

pH >9 during >6 months) Composting (not recommended except for

dedicated users)

SECONDARY TREATMENT Treatment at community / block

level (outside of household) Necessary if project is at

community level, particularly for faeces

Examples: See next slide

primary treatment

secondary treatment

Secondary treatment options for faeces

Type of process Description Is it common?

Storage One year under tropical conditions (28-30 ºC) Very common

Composting Thermophilic preferred (> 50 ºC for > 1 week)

Common

Anaerobic digestion Works well in conjunction with animal manure (household biogas plants), but incomplete pathogen removal

Common in some countries (e.g. China, India, Nepal)

Chemical treatment Mixing with urea to achieve pH increase Experimental stage

Incineration Burning, reuse of ash; complete pathogen kill Not common

based on SchSchönning and Stenström (2004) önning and Stenström (2004)

Recommendations for storage treatment of dry excreta and faecal sludge before use at the household and municipal levels

Treatment Criteria Comment

Storage; ambient temperature 2-20ºC

1.5 – 2 years * Will eliminate bacterial pathogens; re-growth of E. coli and Salmonella may need to be considered if rewetted; will reduce viruses and parasitic protozoa to below risk levels. Some soil-borne ova may persist in low numbers.

Storage; ambient temperature > 20-35ºC

> 1 year Substantial to total inactivation of viruses, bacteria and protozoa; inactivation of schistosome eggs (< 1 month); inactivation of nematode (roundworm) eggs; more or less complete inactivation of Ascaris eggs

Alkaline treatment pH > 9 during > 6 months

If temperature > 35ºC and moisture < 25%, lower pH and/or wetter material will prolong the time for absolute elimination

* Note: no addition of new material: this storage period is taken from the last addition of fresh faeces to the pile

Source: WHO (2006), p. 69

Example for primary treatment of faeces: Standardised UDD toilet in Durban, South Africa

Provides primary treatment for faeces (sanitisation)

Particularly suitable for rural areas

Households reuse their own sanitised faecal matter (no secondary treatment necessary in this case)

Urine is not reused in the Durban example but infiltrated into the soil

Vault closed at bottom

Course 2 Unit 1

Durban (South Africa) rural areas:Council is planning to install 47,000 double-vault UDD toilets by 2007 (17,500 already installed in 2003-2006)

Two openings at the back for removal of dried faeces from faeces vaults (each vault has its own vent pipe) – Photos by Elisabeth,May 2005

Cost information on these toilets:See Course 4 Unit 1 “Financial, institutional, social and policy aspects”

Closed second vault

Continued from previous slide

Plastic UD pedestal and bucket with sand

Waterless urinal (plastic)

Further information on the Durban (=eThekwini) case

With the incorporation of vast rural areas into the eThekwini Municipal area, the Water Services unit identified the need for a training programme for rural communities. A facilitator training manual has been developed for a basic level water and sanitation education programme. The facilitators are chosen from a particular community and trained by Institutional and Social Development (ISD) Consultants.

• Training material is available here: http://www.durban.gov.za/eThekwini/Services/water_and_sanitation/education/sewage_education/rural_water/index_html

Chris Buckley Pollution Research GroupUniversity of KwaZulu-Natal4041 Durban, South AfricaE-mail: buckley@ukzn.ac.za

Important local experts:

Teddy GoundenManager Community Education and Councillor LiaisoneThekwini MunicipalityDurban, South AfricaE-mail: teddygo@dmws.durban.gov.za

Further publications on the Durban UDD toilet experience

Guness, M., Pillay, S., Rodda, N., Smith, M., Buckley, C., and Macleod, N. (2006) Quality of leachate from buried urine diversion toilet waste. Water Institute of South Africa Conference, Durban, South Africa, 22-25 May 2006. Available: www.ewisa.co.za/frame.aspx?url=~/literature/default.aspx&cat=8

Moilwa, N., and Wilkinson, M. (2006) The effect of hygiene communication on emptying of urine diversion toilets. 32nd WEDC International Conference, Colombo, Sri Lanka, November 2006. Available via: http://wedc.lboro.ac.uk/index.php

Course 2 Unit 1

What are alternative options if no agricultural reuse of faeces is possible?

Take to wastewater treatment plant

Take to sanitary landfill

Dump into shallow holes and plant trees (check seepage to groundwater)

Use in aquaculture

Can be burned and disposed with household rubbish

Can you think of other options? Which of these options would be the best for your first ecosan project..??

References used in this presentation Schönning, C. and Stenström, T. A. (2004) Guidelines for the safe

use of urine and faeces in ecological sanitation systems. Report 2004-1, Ecosanres, Stockholm, www.ecosanres.org *

WHO (2006) Guidelines for the safe use of wastewater, excreta and greywater: Volume 4, Excreta and greywater use in agriculture. World Health Organisation, Geneva, available: http://www.who.int/water_sanitation_health/wastewater/gsuww/en/ *

WHO (2004) Guidelines for drinking water quality – recommendations. Geneva, World Health Organisation

Winblad and Simpson-Hébert (2004) Ecological Sanitation – revised and enlarged edition, SEI, Stockholm, Sweden, from www.ecosanres.org *

• Björn Vinnerås, Annika Nordin, Charles Niwagaba, Karin Nyberg: Inactivation of bacteria and viruses in human urine depending on temperature and dilution rate. Water Reserch 42 (2008) 4067 – 4074.

Course 2 Unit 1