WAS711-Water Supply and Sanitation Technologies (1).pptx

Water and Sanitation Technologies

1. WAS711 – WATER SUPPLY AND SANITATION TECHNOLOGIES Engr. (Mrs) Ibiye Daerefa -a Amafabia CENTRE FOR WATER AND SANITATION STUDIES

2. Sanitation Systems Sanitation is a multistep process in which human excreta and waste water are managed from the point of generation to the point of use or ultimate disposal. Sanitation systems are context-specific series of technologies and services for the management of these wastes (or resources) including collection, containment, transport, transformation, utilization or disposal.

3. Sanitation Systems Contd. A sanitation system is therefore, comprised of products (wastes) that travel through functional groups, which contain technologies that can be selected according to the context.

4. Classification of Sanitation Systems Single pit system Waterless pit system without sludge production Pour flush pit system without sludge production Waterless system with urine diversion Biogas system Blackwater treatment system with infiltration

5. Classification of Sanitation Systems Contd. Blackwater treatment system with effluent transport Blackwater transport to (semi-) centralized treatment system Sewerage system with urine diversion.

6. 1. Single Pit System A single pit is used to collect and store excreta Can be used with or without flush water Input can include urine, faeces , anal cleansing water, flush water and dry cleansing materials. Can be used where there is adequate technology to evacuate treat and dispose of the faecal sludge is full or where there is enough space to dig new pits.

7. 2. Waterless Pit System without Sludge Production Uses alternating pits or a composting chamber. Inputs include urine, faeces , organics, anal cleansing water and dry cleansing materials. Anal cleansing water is kept at minimal or excluded where possible. Output is a solid earth like material called pit humus or EcoHumus that can be applied directly to land Can be used where there is limited space and in water-scarce areas.

8. 3. Pour Flush Pit System Without Sludge Production Water-based system using an extraneous water source for flushing. Consists of two alternating pits made of porous materials. Porous materials allow water to seep into the ground Inputs include urine, faeces , flushwater , anal cleansing water, dry cleansing materials and greywater Output is EcoHumus Suited to rural and peri-urban areas with well draining soils and low groundwater table.

9. 4. Waterless System with Urine Diversion Designed to separate urine from faeces Inputs include urine, faeces , anal cleansing water and dry cleansing materials Anal cleansing water is diverted into a soak pit Ash, lime, soil or saw dust is used to cover the faeces Faeces is dehydrated and used as soil conditioner Urine is collected and reused or released to the soil through soak pit Applicable where digging is difficult, water is scarce and/or water table is high

10. 5. Biogas System Uses a biogas reactor to collect, store and treat excreta Inputs include urine, faeces , anal cleansing water, dry cleansing materials, flushwater , organics and, where available, animal waste Output is biogas that can be used for lighting, cooking or electricity generation and sludge that can be applied to after treatment. Best suited to rural and peri-urban areas where there is enough space and regular supply of organic materials.

11. 6. Blackwater Treatment System with Infiltration Water-based system Requires flush toilet and a collection and storage/treatment technology that can hold large volumes of water. Septic tanks or anaerobic baffled reactors or anaerobic filters are used for collection and storage Inputs include urine, faeces , flushwater , anal cleansing water, dry cleansing materials and greywater. Suitable for areas with affordable desludging services Infiltration technology requires space and soil that can absorb effluent

12. 7. Blackwater Treatment System with Effluent Transport Uses household level technology to remove and digest settleable solids Uses a simplified solids-free sewer system to transport effluent to a (semi-) centralized treatment facility. Inputs include faeces , urine, flushwater , anal cleansing water, dry cleansing materials and greywater Appropriate for urban areas where soil is not suitable for infiltration. Also suitable for areas with high groundwater table

13. 8. Blackwater Transport to (Semi-) Centralized Treatment System Water-based system Blackwater is transported to a centralized or semi-centralized treatment facility There is no collection or storage facility onsite Inputs include faeces , urine, flushwater , anal cleansing water, dry cleansing materials, greywater and in some cases, stormwater. Suited to dense urban and peri-urban areas that have no space for collection, storage or emptying facilities. Also suited to areas with high groundwater tables Require constant supply of water to prevent blockage of sewers

14. 9. Sewerage System with Urine Diversion Water based system Requires a urine diverting flush toilet and a sewer Inputs include faeces , urine, flushwater , anal cleansing water, dry cleansing materials, greywater and in some cases, stormwater Appropriate for when there is need for separate urine collection.

15. Class Discussion Which of the above system(s) do we propose for arid regions and why?

16. TECHNOLOGIES FOR USER INTERFACE, COLLECTION/STORAGE, CONVEYANCE/TRANSPORT

17. User Interface (UI) Technologies The user interface must effectively ensure that excreta is hygienically separated from the users. Considerations for choosing any of the listed technologies include: Availability of water for flushing Habits and preferences of users (sitting or squatting, washing or wiping) Special needs of user groups Local availability of materials Compatibility with subsequent collection and storage/treatment or conveyance technology.

18. Types of User Interface Technologies User Interface Dry based Water based U1 – dry toilet U2 – Urine-diverting dry toilet U3 – Urinal U4 – Pour flush toilet U5 – Cistern flush toilet U6 – Urine diverting flush toilet

19. Dry toilets Operates without water May be raised for users to sit or a squat pan for users to squat Excreta drops though a hole to the collection system Can be used in the single pit system or waterless pit system without sludge production.

20. Dry Toilets Contd. Advantages Does not require a constant source of water Can be built and repaired with locally available materials Low capital and operating costs Suitable for all types of users (sitters, squatters, washers, wipers) Disadvantages Odours are normally noticeable Except when deep pits are used, the pile of excreta is visible Vectors such as flies are hard to control except equipped with fly traps or have covers.

21. Urine-Diverting Dry Toilets (UDDT) Operates without water Has a divider for diverting urine and/or wash water away from the faeces Urine is typically collected in front while faeces is collected at the back. Lime, ash or earth should be added to the hole after defecating. Applicable to waterless system with urine diversion.

22. UDDT Contd. Advantages Does not require a constant source of water No real problems with flies and odours if used and maintained correctly Can be built and repaired with locally available materials Low capital and operating costs Suitable for all types of users Disadvantages Prefabricated models not available everywhere Requires training and acceptance to be used correctly Prone to misuse and clogging with faeces The excreta pile is visible Men usually require a separate urinal for optimum collection of urine

23. Urinal Used only for collecting urine. Mostly for men but models for women have also been developed Models for women are equipped with raised foot stands and a sloped channel for conveying urine to collection Models for men can be vertical wall mounted or squat slabs Uses water for flushing but waterless model is becoming popular. Suitable for use with all urine-diverting sanitation systems and biogas system.

24. Urinals Contd. Advantages Waterless urinals do not require a constant water source Can be built and repaired with locally available materials Low capital and operating costs Disadvantages Problems with odours may occur if not used and maintained correctly. Models for women are not widely available

25. Pour flush toilet Built like a cistern toilet but flush water is brought in by the user rather than the cistern. Equipped with a water seal that prevents odours and flies from coming back up the pipe. Pedestal and squat pans can be used Applicable to systems 1, 3, 5-8.

26. Pour flush toilet contd. Advantages The water seal effectively prevents odours The excreta of the previous user is flushed away before the nest user arrives Suitable for all types of users Low capital costs. Operating costs depend on the price of water Disadvantages Requires a constant source of water Requires materials and skills for production that are not available everywhere Coarse dry cleansing material may clog the water seal.

27. Cistern Flush Toilet Consists of a bowl where excreta is deposited and a water tank for flushing Uses a lever for releasing flush water Applicable with systems 6-8

28. Cistern Flush Toilet Contd. Advantages The excreta of the previous user is flushed away before the nest user arrives No real problems with odours if used correctly Suitable for all types of users Disadvantages High capital costs. Operating cost depends on the price of water Requires a constant source of water Cannot be built and/or repaired locally with available materials

29. Urine-diverting Flush Toilet (UDFT) Similar to the cistern flush toilet only the bowl has two compartments for separate collection of urine. Sitting and squatting models exist Urine is collected without water but a small amount of water is diverted to rinse the urine section when flushing Urine is collected separately for further use. Suitable for use with systems 5 and 9

30. UDFT Contd. Advantages Requires less water than a traditional cistern flush toilet No real problems with odours if used correctly Looks like, and can be used almost like a cistern flush toilet Disadvantages Limited availability, cannot be built or repaired locally High capital costs. Operating costs depends on parts and maintenance Labour intensive maintenance Requires training and acceptance to be used correctly Is prone to misuse and clogging Requires a constant source of water Men usually require a separate urinal for optimum collection of urine

31. These refer to technologies that collect and store the products generated at the user interface, including excreta, flush water, anal cleansing water, urine, dry cleansing materials, and any other material added into the user interface. Some storage technologies are designed specifically treat. In these cases, the resulting product is typically pathogen free and can therefore be emptied by hand. Others are designed just to collect and store the products and only passively treat the waste. Storage/Collection Technologies

32. Types of Storage/Collection Technologies Urine storage tank/container Single pit Single ventilated improved pit Double ventilated improved pit Fossa Alterna Twin pits for pour flush Dehydration vaults Composting chamber Septic tank Anaerobic baffled reactor Anaerobic filter Biogas reactor

33. Considerations for selection The choice of technology to adopt will depend on the following considerations. Availability of space Soil and groundwater characteristics Type and quantity of input products Local availability of materials Desired output products Availability of technologies for subsequent transport Financial resources Management considerations User preferences

34. Urine Storage Tank/Container Describes technologies that collect and store urine onsite. The storage tank must then be moved or emptied or into another container for transport. Used for situations where there is the need to use the nutrients in the urine as fertilizer. Applicable to systems 4, 5 and 9.

35. UST/C Contd. Disadvantages Advantages Simple and robust technology Can be built and repaired with locally available materials Low risk of pathogen transmission Stored urine can be used as a fertilizer Small land area required No or low operating costs if self-emptied Mild to strong odour when opening and emptying tank Capital costs can be high (depending on the size and material of the tank) May require frequent emptying (depending on tank size)

36. Single Pit Technology Two processes control the rate of accumulation of user interface products – leaching and degradation. Liquid products like urine and anal cleansing water leach and percolate into the soil through the pit wall and bottom Microbes degrade the solid products Specifically applies to system 1

37. Single Pit Contd. Disadvantages Advantages Can be built and repaired with locally available materials Low (but variable) capital costs depending on materials and pit depth Small land area required Flies and odours are normally noticeable Low reduction in BOD and pathogens with possible contamination of groundwater Costs to empty may be significant compared to capital costs Sludge requires secondary treatment and/or appropriate discharge

38. Single Ventilated Improved Pit (SVIP) This is an improvement over the single pit technology as in this case, a vent pipe is installed in the pit to channel odours away and act as fly trap. Applies to system 1.

39. SVIP Contd. Disadvantages Advantages Flies and odours are significantly reduced (compared to non-ventilated pits) Can be built and repaired with locally available materials Low (but variable) capital costs depending on materials and pit depth Small land area required Low reduction in BOD and pathogens with possible contamination of groundwater Costs to empty may be significant compared to capital costs Sludge requires secondary treatment and/or appropriate discharge

40. Double Ventilated Improved Pit (DVIP) Similar to the SVIP only this is specifically designed for double pit systems (System 2).

41. DVIP Contd. Disadvantages Advantages Longer life than Single VIP (indefinite if maintained properly) Excavation of humus is easier than faecal sludge Significant reduction in pathogens Potential for use of stored faecal material as soil conditioner Flies and odours are significantly reduced (compared to non-ventilated pits) Can be built and repaired with locally available materials Manual removal of humus is required Possible contamination of groundwater Higher capital costs than Single VIP; but reduced operating costs if self-emptied

42. Fossa Alterna An improved variation of the double pit system (system 2) in that it takes less time to treat excreta to produce nutrient rich soil conditioner Pit depth is 1.5 m Cover materials such as soil, ash, and/or leaves are added after each defecation Soil organisms like worm, bacteria and fungi are attracted by the soil and leaves present, accelerating degradation and improving pore spaces. Ash controls flies, reduces odours , and creates alkaline conditions

43. Fossa Alterna Contd. Disadvantages Advantages Because double pits are used alternately, their life is virtually unlimited Excavation of humus is easier than faecal sludge Significant reduction in pathogens Generates nutrient-rich humus with good potential for use as soil conditioner Flies and odours are significantly reduced (compared to non-ventilated pits) Can be built and repaired with locally available materials Low (but variable) capital costs depending on materials; no or low operating costs if self-emptied Requires constant source of cover material Manual removal of humus is required Garbage may ruin end-use opportunities of the product

44. Twin Pits for Pour Flush Specifically suited to the pour flush pit system with sludge production (system 3). Differs from the DVIP and Fossa Alterna in that it is not necessary to add cover materials and it is wet-based. Requires a longer time for degradation and pathogen kill.

45. Twin Pits for Pour Flush Contd. Disadvantages Advantages Because double pits are used alternately, their life is virtually unlimited Excavation of humus is easier than faecal sludge Significant reduction in pathogens Potential for use of stored faecal material as soil conditioner Flies and odours are significantly reduced (compared to pits without a water seal) Can be built and repaired with locally available materials Low (but variable) capital costs depending on materials; no or low operating costs if self-emptied Small land area required Manual removal of humus is required Clogging is frequent when bulky cleansing materials are used Higher risk of groundwater contamination due to more leachate than with waterless systems

46. Use the pattern above to draw up notes for yourself on the rest of the storage/collection technologies as well as conveyance/transport technologies from the compendium. Drop any questions you may have. Your course rep can create a WhatsApp group for just this course, to enable us discuss any questions