Presentation on theme: "Course 2 Unit 1 Part A B C D 1 Teacher Mariska Ronteltap Treatment aspects for urine, faeces and greywater."— Presentation transcript:
Course 2 Unit 1 Part A B C D 1 Teacher Mariska Ronteltap Treatment aspects for urine, faeces and greywater
Content: Part A – Basics and overview Part B – General treatment aspects for urine Part C – General treatment aspects for faeces Part D – General treatment aspects for greywater (in separate file ) Course 2 Unit 1
Part A: Basics and overview Course 2 Unit 1
Where does Course 2 fit in the overall sanitation system scheme? E Course 2, Units 1-7
Where does C2 Unit 1 fit in the overall sanitation system scheme? E
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: What is a pathogen and what is enteric? Course 2 Unit 1
Definition of terms: disinfection, sanitisation, sterilisation TermDegree of pathogen destruction Examples of technical processes DisinfectionPartialTertiary treatment step in conventional wastewater treatment Sanitisation / hygenisation Most or allPrimary or secondary treatment step for urine, faeces or greywater SterilisationAllMedical 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 PathogenDisease caused by pathogen BacteriaAeromonas spp. Escherichia coli Salmonella typhi Salmonella spp. Shigella. spp. Vibrio cholerae Enteritis * Enteritis Typhoid Salmonellosis Shigellosis Cholera VirusesHepatitis A virus Rotavirus Hepatitis Enteritis Parasitic protozoa Giardia intestinalis Cryoptosporidium parvum Giardiasis Cryptosporidiosis HelminthsAscaris 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 lamblia One 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/pi g/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 NH 3 inactivation is slow (NH 3 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 timePossible pathogens in the urine mixture after storage Recommended crops 4°C> 1 monthViruses, protozoaFood and fodder crops that are to be processed 4°C> 6 monthsVirusesFood crops that are to be processed, fodder crops 20°C> 1 monthVirusesFood crops that are to be processed, fodder crops 20°C> 6 monthProbably noneAll 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: MgNH 4 PO 4 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 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 m 3 of urine per week Course 2 Unit 1
Continued from previous slide Left bottle: Stored urine before treatment Right 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 – 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. 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? FactorMechanismTechnology examples Storage time *A longer storage time kills pathogensStorage * TemperatureAt temperatures of 55-65°C all types of pathogens (except bacterial spores) die within hours Composting (thermophilic); solar drying toilets pHHighly acidic or alkaline conditions will have an inactivating effect (adding sawdust, ash or lime increases pH) Alkali treatment AmmoniaPathogens 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 processDescriptionIs it common? StorageOne year under tropical conditions (28-30 ºC)Very common CompostingThermophilic preferred (> 50 ºC for > 1 week)Common Anaerobic digestionWorks well in conjunction with animal manure (household biogas plants), but incomplete pathogen removal Common in some countries (e.g. China, India, Nepal) Chemical treatmentMixing with urea to achieve pH increaseExperimental stage IncinerationBurning, reuse of ash; complete pathogen killNot common Schönning and Stenström (2004) based on Schönning and Stenström (2004)
Recommendations for storage treatment of dry excreta and faecal sludge before use at the household and municipal levels TreatmentCriteriaComment Storage; ambient temperature 2-20 º C 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 > º C > 1 yearSubstantial 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 treatmentpH > 9 during > 6 months If temperature > 35 º C 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 ) 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: d_sanitation/education/sewage_education/rural_water/i ndex_html Chris Buckley Pollution Research Group University of KwaZulu-Natal 4041 Durban, South Africa Important local experts: Teddy Gounden Manager Community Education and Councillor Liaison eThekwini Municipality Durban, South Africa
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, May Available: 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 Available via: 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 , 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: * 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 * 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 – Course 2 Unit 1