Sanitation Systems & Technologies

Transcription

1 1.0 Module 4 Sanitation Systems & Technologies Eawag: Swiss Federal Institute of Aquatic Science and Technology

2 Module 4: Sanitation Chapter 1 Systems & Technologies Definitions and objectives of sanitation systems and technologies Review Introduction to global sanitation situation and the characteristics of the system Non-technical aspects such as socio-cultural, political and financial Systems and technologies classified and described

3 Definitions & Objectives What is water supply & environmental sanitation? Definition: Interventions to reduce people s exposure to disease by providing a clean environment in which to live, with measures to break the cycle of disease. Involves both behaviours and facilities which work together to form a hygienic environment. Simpson-Hebert and Woods, 1998) Water supply (Water treatment & storage) Solid waste management Sanitation (Wastewater & excreta management) Stormwater drainage

4 Definitions & Objectives What waste, resource and management systems are we dealing with? Water supply Sources of waste Houshold water handling Sanitation Waste generation Drainage Wastes Resources Greywater Wastewater Excreta, Faecal sudge Solid Waste Stormwater Processes Storage Transport Treatment Disposal Reuse Management Planning Financing Implementing Operation & Maintenance Regulation & Enforcement

5 Definitions & Objectives What is our focus in this course? Water supply Sources of waste Houshold water handling Sanitation Waste generation Drainage Wastes Resources Greywater Wastewater Excreta, Faecal sudge Solid Waste Stormwater Processes Storage Transport Treatment Disposal Reuse Management Planning Financing Implementing Operation & Maintenance Regulation & Enforcement

6 Definitions & Objectives What are the objectives of sanitation systems? Protect and promote health Work for everyone Protect the environment Be culturally acceptable Be simple Be affordable Sanitation programmes have to comply with all these aspects to become functional, appropriate and sustainable.

7 Definitions & Objectives What is considered as access to basic sanitation? The Millennium Development Task Force on Water defined access to basic sanitation based on the following criteria: Access to sanitation facilities Access to sanitation services Respect of privacy & dignity Healthful environment How can we measure these criteria?

8 Definitions & Objectives What is considered as access to improved sanitation? For monitoring purposes access to improved sanitation is defined in terms of the types of technology and levels of service afforded. improved technologies: not improved technologies: connection to a public sewer connection to a septic system pour-flush latrine simple pit latrine ventilated improved pit latrine (VIP) bucket latrines public latrines open latrines This classification is used to measure coverage and progress of global sanitation.

9 Module 4: Chapter 2 Definitions and objectives of sanitation systems and technologies Review Introduction to global sanitation situation and the characteristics of the system Non-technical aspects such as socio-cultural, political and financial Systems and technologies classified and described

10 Introduction Can we achieve the sanitation targets of the MDG? MDG Goal 7: Halve, by 2015, the proportion of people without sustainable access to safe drinking water and basic sanitation. What progress have we made so far? ( ) (WHO&UNICEF 2004)) 2.6 billion people still lack improved sanitation!

11 Introduction Awareness and priority: Why is sanitation coverage not increasing? Lack of political will Low prestige and recognition Ineffective promotion and low public awareness Institutional issues: No coordination among stakeholders Poor institutional frameworks Legislative and policy issues: Poor policy, at all levels Economic issues: Inadequate and poorly-used resources Neglect of consumer s willingness/ability to pay based on their preferences Capacity and Expertise: Inappropriate approaches Insufficient enforcement Insufficient capacity&expertise

12 Introduction The Bellagio-Principles, to improve environmental sanitation Responsive and accountable to local needs and demands Decision making should involve the participation of all stakeholders Waste should be considered as a resource Waste should be managed as close as possible to its source Slum household, Manila Stakeholders, Africa Compost sieving, India Urine sep., China

13 Introduction What products are we dealing with? Excreta: urine & faeces Blackwater: urine, faeces & flush Yellow-water: separated urine Greywater: wastewater from kitchen, bath, shower. Faecal sludge: solids and liquids accumulating in sanitation systems A sanitation system must manage all products generated!

14 Introduction Characteristics of waste products Total Greywater*** Urine Faeces Volume [l/cap yr] Nutrients Nitrogen 2-4 kg/cap yr 5% 85% 10% Phosphorous kg/cap yr 10%** 60% 30% Potassium kg/cap yr 34% 54% 12% COD 30kg/cap yr 41% 12% 47% Faecal coliforms /100ml 0* /100ml * healthy people ** can be as high as 50%, depending on washing and dish-washing powder used *** values representative for industrialized countries

15 Introduction Characteristics of waste products Greywater Urine Faeces Chemical contamination Fats, oils and toxic substances org. compounds, chlorides, metals Micro-contaminants e.g. hormons & antibiotics Microcontaminants e.g. Heavy metals Biological contamination Pathogens bacterias, viruses, helminths, protozoa Almost sterile i.e. crosscontamination from feaces Pathogens bacterias, viruses, helminths, protozoa Value Reuse potential for irrigation or municipal and nonpotable domestic use Nutrients (N, K and P etc.) => ideal fertilizer Good soil conditioner, but only little nutrients

16 Module 4: Chapter 3 Definitions and objectives of sanitation systems and technologies Review Introduction to global sanitation situation and the characteristics of the system Non-technical aspects such as socio-cultural, political and financial Systems and technologies classified and described

17 Systems and Technologies What are the Functional Groups through which the products flow? Technologies which perform the same, or similar function, are grouped into Functional Groups User Interface Collection and Storage/ Treatment Conveyance (Semi-) Centralised Treatment Use and/or Disposal e.g. Dry Toilet or Pour Flush Toilet e.g. Septic Tank e.g. Simplified Sewer or Tank Lorries e.g. Anaerobic Baffled Reactor or Waste Stabilisation Pond e.g. Composting or Leaching Field Input products safe & valuable output products

18 How can the Functional Groups be linked? Systems and Technologies User Interface e.g. Flush-Toilet, Pit Latrine Collection and Storage/ Treatment e.g. Septic Tank Conveyance e.g. Simplified Sewer, Tank Lorries Use and/or Disposal e.g. Composting or Leaching Field Semi-Centralised Treatment e.g. Anaerobic Baffled Reactor, Waste Stabilisation Pond Functional Groups have to be linked to a functional system

19 Systems and Technologies Which technologies can perform which function? User Interface Collection and Storage/ Treatment Conveyance (Semi-) Centralised Treatment Use and/or Disposal Dry Toilet Urine Diverting Dry Toilet Urinal Pour-Flush Toilet Flush Toilet Urine Diverting Flush Toilet Single Pit Single VIP Dehydration Vaults Septic Tank Composting Chamber Anaerobic Baffled Reactor Anaerobic Filter etc. Human-Powered Emptying and Transport Motorized Emptying and Transport Simplified Sewers Small-Bore Sewer Conventional Gravity Sewer Jerry Can/Tank etc. Anaerobic Baffled Reactor Anaerobic Filter Trickling Filter Waste Stabilisation Ponds Activated Sludge Constructed Wetland Co-composting etc. Application of Urine Application of Dehydr. Faeces Compost Irrigation Aquaculture Soak Pit Leach Field Land Application Surface Disposal etc. Only selected combinations of technologies will lead to functional systems.

20 How can sanitation systems be classified? Determined mainly by the user interface, there are 8 technically feasible system templates, classified in two categories: Systems and Technologies Waterless Systems System 1: Single Pit System System 2: Waterless Alternating Double Pits System 4: Waterless Urine Diversion Water based Systems System 3: Pour Flush with Urine Diversion System 5: Decentralised Blackwater Treatment System 6: (Semi-) Centralised Blackwater Treatment System 7: Sewerage with (Semi-) Centralised Treamtent System 8: Sewerage with (semi-) centralized treatment Most system templates have several alternative configurations. The most appropriate system option has to be selected on a case-tocase basis.

21 Technologies for the user interface Systems and Technologies User Interface Collection and Storage/ Treatment Conveyance (Semi-) Centralised Treatment Use and/or Disposal Dry Toilet Urine Diverting Dry Toilet Urinal Pour-Flush Toilet Flush Toilet Urine Diverting Flush Toilet Single Pit Single VIP Dehydration Vaults Septic Tank Composting Chamber Anaerobic Baffled Reactor Anaerobic Filter etc. Human-Powered Emptying and Transport Motorized Emptying and Transport Simplified Sewers Small-Bore Sewer Conventional Gravity Sewer Jerry Can/Tank etc. Anaerobic Baffled Reactor Anaerobic Filter Trickling Filter Waste Stabilisation Ponds Activated Sludge Constructed Wetland Co-composting etc. Application of Urine Application of Dehydr. Faeces Compost Irrigation Aquaculture Soak Pit Leach Field Land Application Surface Disposal etc.

22 Systems and Technologies Technologies for the user-interface Input Products User Interfaces Output Products Urine Faeces Beigewater Urine Faeces Dry Toilet (1) (2) Urine Diverting Dry Toilet Excreta Urine Faeces Beigewater (3)

23 Technologies for the user-interface Systems and Technologies Input Products Urine Faeces Flushwater Beigewater User Interfaces Pour-Flush Toilet (1) Out Products Blackwater Urine Faeces Flushwater Cistern-Flush Toilet (2) Blackwater Beigewater

24 Systems and Technologies Technologies for collection and storage/treatment User Interface Collection and Storage/ Treatment Conveyance (Semi-) Centralised Treatment Use and/or Disposal Dry Toilet Urine Diverting Dry Toilet Urinal Pour-Flush Toilet Flush Toilet Urine Diverting Flush Toilet Single Pit Single VIP Dehydration Vaults Septic Tank Composting Chamber Anaerobic Baffled Reactor Anaerobic Filter etc. Human-Powered Emptying and Transport Motorized Emptying and Transport Simplified Sewers Small-Bore Sewer Conventional Gravity Sewer Jerry Can/Tank etc. Anaerobic Baffled Reactor Anaerobic Filter Trickling Filter Waste Stabilisation Ponds Activated Sludge Constructed Wetland Co-composting etc. Application of Urine Application of Dehydr. Faeces Compost Irrigation Aquaculture Soak Pit Leach Field Land Application Surface Disposal etc.

25 Collection and storage / treatment technologies VIP latrine (ventilated improved pit latrine) Systems and Technologies mesh traps flies ( mm mesh) size Naturally induced ventilation with screened ventilation pipe removes odor and prevents escape of flies Should extent > 0.5 m above superstructure Flies are attracted by light from pipe + odors and flies reduced - difficult to construct properly - more expensive than simple pit latrine

26 Urine diversion latrines with double deyhdration vaults Systems and Technologies Collection and storage / treatment technologies Urine and Faeces are separated Add ash, sand or lime + no waste, but fertilizer + simple to design + little flies or odours if used correctly + easy and safe handling of dried material Urine is collected in tanks and is reused as liquid fertilizer Faeces are dehydrated in 2 alternating chambers and used as soil conditioner Requires: - special squatting pan - education and acceptance - constant source of ash, sand etc. - a use or discharge point for urine

27 Alternating water-based pits flushing of excreta with 2-3 L using a syphon (water seal) permanent pit(s) constant operation Systems and Technologies Collection and storage / treatment technologies Pour-Flush toilets with double pit single pit latrine with water-sealed pan for pour-flush + reduced odour - higher investment costs - water must be available

28 Septic tank = sedimentation tank in which settled sludge is partially stabilised by anaerobic digestion Systems and Technologies Collection and storage / treatment technologies most frequent onsite treatment unit worldwide Consists of 2 to 3 compartments + simple, little space required because of being underground + low O&M costs - little removal of dissolved and suspended matter (COD removal approx. 50%) - high investment costs

29 Anaerobic baffled reactor (baffled septic tank) Systems and Technologies Collection and storage / treatment technologies Sedimentation chamber for removal of solids 2 to 5 anaerobic chambers for removal and digestion of organics intensive contact between resident sludge and fresh influent Improvement of a septic tank Treatment efficiency: 65 to 90% COD removal + simple, high treatment efficiency, hardly any blockage + high removal efficiencies, also for suspended and dissolved solids - construction and maintenance more complicated than conventional septic tank

30 Systems and Technologies Conveyance technologies User Interface Collection and Storage/ Treatment Conveyance (Semi-) Centralised Treatment Use and/or Disposal Dry Toilet Urine Diverting Dry Toilet Urinal Pour-Flush Toilet Flush Toilet Urine Diverting Flush Toilet Single Pit Single VIP Dehydration Vaults Septic Tank Composting Chamber Anaerobic Baffled Reactor Anaerobic Filter etc. Human-Powered Emptying and Transport Motorized Emptying and Transport Simplified Sewers Small-Bore Sewer Conventional Gravity Sewer Jerry Can/Tank etc. Anaerobic Baffled Reactor Anaerobic Filter Trickling Filter Waste Stabilisation Ponds Activated Sludge Constructed Wetland Co-composting etc. Application of Urine Application of Dehydr. Faeces Compost Irrigation Aquaculture Soak Pit Leach Field Land Application Surface Disposal etc.

31 Conveyance technologies Solids free sewer Simplified sewer especially adequate where septic tanks already exist. strict design criteria - relies on good solid removal in septic or interceptor tanks less strict design standards (e.g. fewer manholes, smaller pipe diameters, flatter gradients, shallow etc.) sewers laid inside housing blocks or under pavements. + cheaper

32 Conveyance technologies Motorized emptying & transport Human-powered emptying & transport + High efficiency - High O&M and capital cost - Spare parts often lacking - Difficulty in manoeuvring (vehicle size, traffic congestion, infrastructure) + Low-cost operation and maintenance + Maintenance skills and spare parts available - Limited efficiency

33 User Interface Collection and Storage Semi-centralised treatment technologies Conveyance (Semi-) Centralised Treatment Systems and Technologies Reuse and Disposal Dry Toilet Urine Diverting Dry Toilet Urinal Pour-Flush Toilet Flush Toilet Urine Diverting Flush Toilet Single Pit Single VIP Dehydration Vaults Septic Tank Composting Chamber Anaerobic Baffled Reactor Anaerobic Filter etc. Human-Powered Emptying and Transport Motorized Emptying and Transport Simplified Sewers Small-Bore Sewer Conventional Gravity Sewer Jerry Can/Tank etc. Anaerobic Baffled Reactor Anaerobic Filter Trickling Filter Waste Stabilisation Ponds Activated Sludge Constructed Wetland Co-composting etc. Application of Urine Application of Dehydr. Faeces Compost Irrigation Aquaculture Soak Pit Leach Field Land Application Surface Disposal etc.

34 Semi-centralised treatment technologies Systems and Technologies Constructed wetlands (here: horizontal sand filter) For treatment of (pre-settled) domestic or industrial WW (COD < 500mg/l and low solids) phragmites and typha Inlet pipe sand & gravel filter, permanently soaked with water Outlet pipe + high treatment efficiency (up to 95% COD removal), no WW above ground, no nuisance of odour, high nutrient removal - high space requirement, costly (gravel), great care required during construction

35 Systems and Technologies Waste stabilization ponds Semi-centralised treatment technologies A pond-system comprises: anaerobic sedimentation ponds, alternating facultative (aerobic) ponds and several maturation ponds (post-treatment ponds) Anaerobic Pond Facultative Pond Maturation Ponds Design Deep (2-5m) and highly loaded but rather small area Shallow (<1.5m) but large Oxygen supply (algae, wind, artificial aeration) Shallow (<1m) but large area Flow Hydraulic retention time: 1 to 3 days Hydraulic retention time: 10 to 20 days Hydraulic retention time: 10 days Function Sedimentation and anaerobic stabilisation of sludge (BOD reduction 40-50%) settling Aerobic degradation of suspended and dissolved matter (BOD reduction 50-70%) degradation Final sedimentation of suspended solids, bacteria mass and pathogens hygienization

36 Systems and Technologies Semi-centralised treatment technologies Waste stabilization ponds Degradation of organic substances in facultative ponds:

37 Semi-centralised treatment technologies Systems and Technologies Waste stabilization ponds Pros and Cons + Can treat high strength wastewater to high quality effluent + Generally reliable and good functioning + Very inexpensive compared to other centralized options - Not always appropriate for colder climates - Potential for bad odours if poorly designed - Requires expert design and supervision - Requires a lot of space Ideal for developing countries if enough space and supervision available!

38 Systems and Technologies Use and/or disposal technologies User Interface Collection and Storage/ Treatment Conveyance (Semi-) Centralised Treatment Use and/or Disposal Dry Toilet Urine Diverting Dry Toilet Urinal Pour-Flush Toilet Flush Toilet Single Pit Single Pit VIP Alternating Dry Double Pit Alternating Wet Double Pit Double Dehydr. Vaults Aquaprivy Manual Emptying Mechanical Emptying Simplified Sewers Small-Bore Sewer Conventional Gravity Sewer Jerry Can/Tank Imhoff Tank Anaerobic Baffled Reactor Anaerobic Filter Trickling Filter Waste Stabilisation Ponds Finishing Pond Application of Urine Application of Dehydr. Faeces Compost Irrigation with Wastewater Aquaculture Soak Pit Septic Tank Composting Chamber Constructed Wetland Co-composting etc. Leaching Field Incineration Land Application Surface Disposal

39 Systems and Technologies Wastewater disposal technologies Leach fields = system of trenches that is used to dissipate the effluent from a septic tank for discharge of non-solid septic tank effluent sand and/or topsoil fabric, to prevent plugging of pipe clean rock + little maintenance required - Space and skills required! perforated distribution pipe

40 Systems and Technologies Wastewater disposal technologies Soak pits = covered, porous-walled chamber that allows water to slowly soak into the ground. for non-solid septic tankeffluent (clogging!) + simple and cheap + little space required - not adequate for shallow ground water table (>1.5 m) - not adequate in clay or rocky soils Between 1.5 and 4 m deep

41 Systems and Technologies Use of output products Wastewater irrigation Recommendations to limit health risks on farm: Use of wastewater only after secondary treatment (i.e. physical and biological) Use of appriopriate irrigation system: 1) Drip irrigation (ideal, but more costly) 2) Furrow irrigation (cheap, but more evaporation loss) Crop restriction: Growing e.g. fibres (cotton), tobacco or fruit trees is generally safer than vegetables or salad Increasing the period between wastewater irrigation and harvesting/consumption Farmer fetching faecal sludge Wastewater can be used for irrigating agricultural land, if appropriate precautions have been taken.

42 Quality standards for use of output products Systems and Technologies Waste product Urine Treated Wastewater Greywater Excreta (untreated FS) Reuse Application Irrigation of food and fodder crops to be processed Irrigation of food and fodder crops to be processed, fodder crops unprocessed Irrigation of all crops Unrestricted irrigation Restricted irrigation Localized irrigation Unrestricted irrigation Restricted irrigation Agriculture (Soil conditioner) Aquaculture 1 month storage (4 C) 6 month storage (4 C) 6 month storage (20 C) EC/100ml EC/100ml < EC/100ml <10 3 EC/g total solids 10-6 EC/100ml Guidelines Waste products can be reused in agriculture, aquaculture and biogas plants. or 1 Helm.eggs/l All waste products can be reused if EC/100ml safety guidelines are met. 1 Helm.eggs/l 1 Helm.eggs/l Waste recycling < EC/100ml is practised <1 successfully Helm.eggs/l in many countries. <1 Helm.eggs/l <1 Helm.eggs/g total solids 1 Helm.eggs/l 1 month storage (20 C) No detectable trematode eggs

43 How to design a sanitation system? Systems and Technologies User Interface Collection and Storage/ Treatment Conveyance (Semi-) Centralised Treatment Use and/or Disposal Dry Toilet Urine Diverting Dry Toilet Urinal Remember: Only selected combinations of technologies result in functional systems! Single Pit How to proceed: Single Pit VIP Alternating Dry Double Pit Manual Emptying Mechanical Emptying Simplified Sewers Imhoff Tank Anaerobic Baffled Reactor Anaerobic Filter Pour-Flush Toilet 1.) Identify Alternating the Wet types of Small-Bore products Sewer that are Trickling generated. Filter Flush Toilet Double Pit Conventional Waste Double Dehydr. Gravity Sewer Stabilisation 2.) Select Vaults the most appropriate system Jerry Can/Tank Ponds templates. Aquaprivy Finishing Pond 1.) Identify the types of products that are generated. Application of Urine Application of Dehydr. Faeces Compost Irrigation with Wastewater Aquaculture Soak Pit 3.) Select the specific technologies for each product for each Septic Tank Constructed Leaching Field process Composting in each of the system templates Wetland identified. Incineration Chamber Co-composting Land Application 4.) Select the most site-specific system etc. option based on Surface the Disposal 4.) Select the most site-specific system option based on the social, economic, and resource aspects.

44 Systems and Technologies 1st Example: Waterless system with urine diversion User Interface Collection and Storage/ Treatment Conveyance (Semi-) Centralised Treatment Use and/or Disposal Urine Diverting Dry Toilet & Urinal Faeces Double Dehydration Vaults Storage Tank Human Powered Emptying and Transport Jerry Can / Tank Application of Faeces Application of Urine Urine Greywater Greywater Treatment

45 Systems and Technologies 2nd Example: Water-based, alternating double pit User Interface Collection and Storage/ Treatment Conveyance (Semi-) Centralised Treatment Use and/or Disposal Pour Flush Greywater Blackwater Twin Pits for Pour- Flush Greywater Treatment Human Powered Emptying and Transport Compost/ EcoHumus

46 Systems and Technologies User Interface 3rd Example: (Semi-) centralised blackwater treatment system Collection and Storage/ Treatment Conveyance (Semi-) Centralised Treatment Use and/or Disposal Pour Flush Toilet Cistern Flush Greywater Blackwater Greywater Treatment Septic Tank ABR Anaerobic Filter Faecal Sludge Simplified Sewers Solids-free Sewers Human- Powered E &T Motorized E&T Trickling Filter UASB Waste Stabilisation Ponds Aerated Pond Constructed Wetlands Floating Plant Wetland Co-Composting Thickening Ponds (Un-)planted Drying Beds Biogas Reactor Irrigation Aquaculture Ponds Disposal/ Recharge Select the most appropriate system configuration! Surface Disposal Land application.

47 Systems and Technologies Emergency sanitation Construction of an emergeny latrine

48 Systems and Technologies Open field defecation Design criteria: Far from water source (50 m) and storage Downhill of settlements (leakage) Far from public buildings and roads Security screen to provide minimum privacy Including hand washing facilities Better suited for hot dry climates Immediate action measures First clearing of scattered excreta! + rapid and easy - lack of privacy

49 Systems and Technologies Shallow trench defecation Immediate action measures Shallow trench Design criteria: cm deep cm wide provide shovels to allow each user to cover its excreta with soil + rapid (1 worker can dig 50 m of trench per day) + covered with soil - limited privacy - considerable space required

50 Systems and Technologies Bucket / container latrines Urinals with soakage pit Immediate action measures

51 Systems and Technologies Emergency sanitation planning Recommended minimum objectives for safe excreta disposal Immediate Short-term Long-term (max. 1 month) (max. 6 months) (3 years) Quantity 1 cubicle/space to 100 persons 1 cubicle/space to 50 persons 1 cubicle/space to 20 persons Maximum walking distance 70m (one way) 50m (one way) 25m (one way) Quality Technically basic Barely socially and culturally acceptable Technically appropriate Socially and culturally acceptable Technically very appropriate Very socially and culturally acceptable Access to facilities 50% of affected population 75% of affected population 95% of affected population Open/trench defecation field Communal pit latrines Household pit latrines

52 physical aspects physical aspects Non-technical Aspects Criteria influencing the selection of sanitation systems political & institutional aspects financial & economical aspects socio-cultural aspects

53 Criteria influencing the selection of sanitation systems Physical aspects Availability of space (pit emptying) Groundwater level Water availability Climate (temperature, rainfall) Ground conditions (rock, sand, loam,...) Non-technical Aspects Flooded yard Narrow alley: pit emptying difficult

54 Political & institutional aspects Non-technical Aspects Criteria influencing the selection of sanitation system Regulations and standards Organizational setup and responsibilities Political will and support Bureaucracy

55 Criteria influencing the selection of sanitation systems Financial & economical aspects Non-technical Aspects Availability of local skills, manpower & resources Availability of local materials and tools Affordable technology Willingness to pay and appropriate service level Operation and maintenance Availability of credits and loans Construction of baffled reactor

56 Non-technical Aspects What are financial and economic costs? Financial costs Economic costs VIP latrine? Tank lorry Cost relevant only for individual household, enterprise or institution. e.g. Price charged to household for pit emptying Cost shaped to allow accounting and comparison of treatment plants and management systems.

57 Non-technical Aspects How to finance a sanitation programme? Two financial tools: Subsidies Paid directly to user? Subsidising only components? Subsidising only overhead costs of sanitation programme? Concerns: Expensive (realistic?) Feeling of ownership and responsibility? Loans Can users pay interest rate? Possibility: Subsidized rate of interest Who will get loans? Is money lent actually spent on sanitation? Organisation and control needed!

58 Potential of decentralized sanitation systems Non-technical Aspects Minimizes waste of freshwater for transportation Tailoring to local conditions Responsiveness to local demands Lower risks system fails Permits waste segregation at source Increases local wastewater reuse opportunities Permits stepwise development and investment of sanitation system

59 Module 4: Chapter 6 Definitions and objectives of sanitation systems and technologies Review Introduction to global sanitation situation and the characteristics of the system Non-technical aspects such as socio-cultural, political and financial Systems and technologies classified and described

60 Review Review Sanitation involves both, facilities and behaviour. A sanitation system should include all waste products, from cradle to grave. Only selected combinations of technologies result in a functional sanitation system. The most appropriate system option has to be selected on a case-to-case basis, considering hard and soft aspects. Decentralized systems are often more appropriate in developing countries. Waste products are valuable and should be considered as resources.

61 Credits Credits Publisher: Eawag, Sandec: Department of Water and Sanitation in Developing Countries, P.O. 611, 8600 Dübendorf, Switzerland, Phone +41 (0) , Fax +41 (0) Editors: Elizabeth Tilley Concept and Content: Manuel Henseler and Karin Güdel Layout: Manuel Henseler and Karin Güdel Copyright: Eawag/Sandec 2008 Eawag/Sandec compiled this material, however much of the text and figures are not Eawag/Sandec property and can be obtained from the Internet. The modules of the are not commercial products and may only be reproduced freely for non-commercial purposes. The user must always give credit in citations to the original author, source and copyright holder. This Powerpoint presentation and its matching lecture notes are available on the CD of Sandec s Training Tool and can be ordered at: info@sandec.ch