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[ Module 3] Key issues of urban sanitation. Understand key issues of urban sanitation. Key elements of urban sanitation. Options for urban sanitation and key factors determining specific requirements. Options in detail. Slum connectivity.
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Understand key issues of urban sanitation Key elementsofurban sanitation Options for urban sanitation and key factors determining specific requirements Options in detail Slum connectivity Collectionanddiscussionofcasesfromparticipants
Key elements of urban sanitation decentralizedon-site sanitation Leach Pit Leaching field Land Application decentralizedon-site / off-site sanitation Septic Tank Emptying Soak Pit Transportation User Interface /toilet Sewage Treatment Plant centralized off-site sanitation Drying Beds Conveyance 3
Key elements of urban sanitation – a schematic view source: MoUD, WSP: Technology Options for Urban Sanitation in India – A Guide forDecision Making, September 2008, page 17 4
Options for urban sanitation and key factors determining specific requirements Settlement • densityandspace • sourceofwater • existingstructures Size Location • < 1 lakhpopulation • 1-10 lakhpopulation • million plus • megacities • soil • groundwater • topography System • on-site / off-site • decentralized / centralized • Key questions: • Can wastewaterbedisposed on site? • Whenandwhereisseweragerequiredandviable? • Whicharrangementsarerequiredforthemanagementofwastewaterandfecalsludge? • Howdoesthedemandforreuseinfluencethechoiceoftechnology? 5
Key factor settlement • Housingandpopulationdensity • Source ofwater • protectionofwaterfromwellsortubewells • amountofwastewaterisfunctionofdensity • availibiltyofspaceisfunctionofdensity 6
Key factor size and treatment options source: Centrefor Science and Development: Policy Paper on Septage Management in India, May 2011, page 22, adapted 7
Key factor location • Soil type • High groundwaterlevel • Topography – high altitudes, steepterrain • baseofleachpitswithenoughdistancefromgroundwater • rockygroundincreasescostsforundergroundfacilities • reducesscopeforinfiltrationofwastewater • operationofsoakaways • spacelimitations • sewerstobelaidbelowwatertabletoensureself-cleansing • flushingwater in latrinesmayfreeze • rockygroundincreasescosts • possibleintrusionofgroundwaterintosewer • frozen, impermeable groundduringwinterlimitssoakingcapacities • high pumpingrequirements / costs • sewercanbegravitydriven 8
Key factor system • off-site • on-site • requiressewersystem • lowdensityhousing • high densityhousing • lowwaterconsumption • reliablewatersupply • availabilityofservicestoremoveandtransportsludgesand septage • sufficient fall toavoidpumping in sewers • groundconditionsallowabsorptionofwastewaterandavoidcontaminationofgroundwater • high maintenancecosts in areaswithinsufficient MSWM 9
Options in detail decentralizedon-site sanitation Leach Pit Leaching field Land Application Treatment & disposal Septic Tank Emptying Soak Pit Transportation Septage Management User Interface /toilet Sewage Treatment Plant centralizedsystem Drying Beds Conveyance Access totoilets decentralizedtreatmentsystem 10
Access to toilets Wheretolocate?Whattoconsider? Common weaknessesandthreats Actions identified in CSPs Typesoftoilets Best practiceexample 11
Access to toilets – where to locate, what to consider? Consider special needs of women, children and disabled • Household • School andpre-school • Group of HH All market areas and public places to have toilet and urinal facilities Proper excreta disposal facility • Location • Institutional • Community O & M • Public Provision for maintaining aesthetic look User charges 12
Access to toilets • Coverage • Construction • availability of land • gaps in coverage of wards • lack in commercial areas • gender issues • barriers • no water supply • discharge to open drains / water bodies Common weaknessesandthreats • Behaviour • O & M • hygienic unawareness • habit of open defecation and urination • widespread willingness to pay for service • limited opening times • cleaning • maintenance • monitoring • Regulation • unclear responsibilities • no dedicated units • family card system not realistic • complicated prosecution of violations
Access to toilets • Communities • Technology, planning and construction • awareness campaigns • behaviour change • community involvement in O&M • community involvement in financing Actions identifiedby CSPs • gender sensitivity • water supply • floating population • mobile facilities • Regulations • target standards for seats / inhabitants • target standards for access within distance • guidance documents • 24/7 access • map of existing public toilets • map of toilets in public buildings • SOPs • inspection and monitoring protocol • BOT approaches • O & M
Operates without water • Placed over a pit • Can be built anywhere with locally available material. Dry toilet • Operates without water • Separates the solid (feces) from the liquid (urine) • Separation reduces the smell Urine diverting dry toilet • Water seal thus reducing the odor • Flushed by stored water • Regular water supply is a must Pour flush toilet Cistern-flush toilet • Modern version of pour flush toilet The elements of sanitation – types of toilets to on-site dry system User interface (User, behavior & Toilets) toon- oroff-site waterreliantsystem
On-site–dry system 16 Disposal / Off-site use Wastewater type On-site system On-site treatment Simple pit latrine Composting Relocation of latrine after the pit is full or agricultural use of composted material Feces & urine Ventilated improved pit latrine, VIP Composting latrine
On-site water reliant systems Wastewater type On-site system On-site treatment Disposal / Off-site use Leach pit Agricultural use of composted material & water leakage into groundwater Composting & degradation of wastewater constituents Black water Individual septic tank Anaerobic degradation Sludge disposal at environmentally acceptable areas Agricultural use of effluent Overhung latrine Effluent discharge into water body
Good Examples: Tiruchirapalli MC, Tamil Nadu • Set-up • Situation • Process • Lead agency: local NGO • frequentoutbreaksofwaterbornediseases • Needs assessment in communitiestoidentifyinterventionsrequired • WaterAid • renovationoftoilets • communitytoiletswereavailable (under MC) but not wellmanagedandmaintained, nowatersupplyandnodisposal, frequent open defecation • communitybasedsystemfor O&M • Holisticdevelopmentapproachcombinedprovisionoftoiletswithempowermentofcommunitiestoimprovetherihealth, environmentandlivingstandards • involvementofwomen‘sgroups: • establishedWomen‘snSelf Help Group • formedSanitationand Hygiene Education Teams whoimplementedandmonitoredthewholeprogrammeatcommunitylevel • open drainswithwastewater, fecesand HH wastecrossingquarter • effectivepartnershipbetween MC, communitiesand NGOs to manage andmaitaintoilets • beforetheprojectthetown was oneofIndia‘s least hygieniccities • Activities • renovationandconstructionoftoilets (communityand private) withfinancialsupportfromWaterAid • landprovidedby MC includingwaterandelectricitysupply • identificationandcapacitationofworkforcefordaily O&M • establishinhsustainablebusiness plan for O&M • sustainablefinancialmanagement: • pay & usesystem • profitsusedforawarenessgenerationandnecessaryworks • rotatingresponsibiltywithin SHGs • latermen‘sandchildren‘sgrouopswereestablishedtopartticipate in sanitationactivities • 211 approvedand 75 unapprovedslumswithapprox. 23% ofthecity‘spopulation source: http://www.awasla.org/Docs/ACCESS_ahmedabad_case_study.pdf
Good Examples: Tiruchirapalli MC, Tamil Nadu • Sustainability • Lessons learnt • health, hygieneandnutrition • The townisnowrankedas 6th in sanitationrankingof Indian cities • Key successfactors: • supportive MC understandingand sensitive totheissuesandsupportivetocommunityaction • communityinvolvementandsupport • involvementofwomen • inclusivecommunitymanagement • ownership • socioculturalandinstitutionalaspects • Principalchallenge was togenerateinterest in thecommunitiesincludingwillingnesstopayfortoiletutilization • financialandeconomicissues • Localpoliiticansinterferedwiththeprojectagitatingagainstuserfees • environmentandnaturalresources • NGO hadtoensurecontinuouscommunityworkincluding HH visits • Land tenureandwaterandelectrcitysupplyprovidedbysupportive MC • technologyandoperation • gendermainstreamingandempowermentofwomen source: http://www.awasla.org/Docs/ACCESS_ahmedabad_case_study.pdf
Septage management Definition of septage Common weaknessesandthreats Actions identified in CSPs Management Best practiceexample 20
Septage – Definition and characteristics Whatis septage? • “Septage” is septic tank sludge that is a combination of raw primary sludge and anearobically produced raw sludge. Somecharacteristics • Septage has offensive odour, • contains significant levels of grease, grit, hair, debris and pathogenic micro organisms. Can characteristicsvary? • The physical and chemical characteristics vary on size and design of the storage facility, pumping frequency and climatic conditions.
Septage management • Construction • Natural conditions • unscientific construction • discharge to open water bodies / drains • lack of land for treatment and disposal facilities • high groundwater table Common weaknessesandthreats • Regulation • O & M • overlapping functions and roles • lack or weak enforcement of regulations and bye-laws • low knowledge on spatial distribution • weak maintenance • lack of cleansing • manual desludging • lack of mechanization and equipment • no treatment / uncontrolled disposal • no monitoring and control
Septage management • Communities / households • Planning, construction, system upgrade • awareness campaigns • behaviour change • community involvement • O&M and private / community level • rehabilitation of existing tanks • upgradation of existing tanks • avoid or treat sewage outflow into drains • integrate tanks into off-site treatment system Actions identifiedby CSPs • Regulations • establish building codes for septic tanks • establish bye-laws for on-site sanitation, and septage management • establish on-site sanitation monitoring framework • O & M • clear demarcation between on-site and off-site systems • mapping of all septic tanks • sustainable operator model • SOPs
Septage management Whatis septage management? It is the process of managing of septic tanks including desludging, transporting, treating, and disposal of its contents. 1 2 7 3 4 6 5
Management of effluent OR Correct Practice Wrong Practices
Conventional Septic tank Improved Septic tank
Septage Treatment Options Conventionalseptic tank Liquid effluentdisposal / reuse Land application Pre-treatment ofseptage Treatment at CETP Treatment atindependendfacilities • Improved septic tank / Anaerobic baffled reactor • Non- conventional Management of septage
Good Examples: Septage treatment facilities in Surabaya, Indonesia • Set-up • Situation • Framework • only 11 citieshave WWTP • STP opertaedbylocalagency • City governmentframework: • nuisancepermits • tippingfees • waterqualitymanagement • waterpollutioncontrol • Governmentestablished 150 septage treatmentplants in thecountry • sludgecollectionandtransportationprovidedby private haulertruckservice • one such plant was established in Surabaya (3 mil. inhabitants) • Sanitationagencycollectsmonthlytippingfeesbased on septage volume • Service providershavelicensesforcollection, transportanddisposal • 87% ofthehouseshaveaccesstoimprovedsanitationfacilities source: Centrefor Science and Development: Policy Paper on Septage Management in India, May 2011, page 26
capacity: 400m³/day modifiedactivatedsludgeprocess dryingbeds manure source: Centrefor Science and Development: Policy Paper on Septage Management in India, May 2011, page 26
Centralized systems Common weaknessesandthreats Actions identified in CSPs Process Summary centralized – de-centralizedsystems 34
Centralized systems • Natural conditions • topography • bedrock • high groundwater table • Construction • sewer connection only for black water • no connection of open drains • missing links in network • inadequate pumping capacities • inadequate treatment technology • inadequate capacity of the system • Regulation Common weaknessesandthreats • high connection charges • high service costs • overlapping functions and roles • lack or weak enforcement of regulations and bye-laws • Coverage • O & M • low coverage • low connection • low availability of land for facilities and disposal • narrow streets • leakages in network • choking • no monitoring of functionality • no regular O&M • underutilization of the system • no reuse of treated water
Centralized systems • Planning, construction, system upgrade Actions identifiedby CSPs • training for plumber certification • STP to receive and treat septage • Regulations • waste water quality monitoring protocol • O & M • clear demarcation between on-site and off-site systems • mapping of sewerage and connections • address choking complaints • bulk metering at trunk lines and STP inlet • O&M contracts ROT (rehabilitate, operate, transfer) approach • SOPs
Elements and options or centralized treatment systems Sourcesofwastewater Central treatment Disposal Conveyancesystem = sewer Conventionalsewer Simplifiedsewer Solid freesewer Wastestabilizationponds Constructedwetlands • High investment • Specialized knowledge • Maintenance • Less stringent design standards • Cheaper • Laid under sidewalks/in front of backyards • Connected to the outflow of a septic tank or interceptor tanks • Laid at shallow depth • Follow the topography • For high strength & centralized treatment facilities • Require large area • Anaerobic ponds, facultative and aerobic ponds • Suitable for pre-settled wastewater • Require specialized knowledge • High investment
De-centralized systems Features of de-centralizedsystems Process O & M Summary centralized – de-centralizedsystems Best practiceexample 38
De-centralised Waste Water Treatment Systems - DEWATS • DEWATS allows treatment of organic waste water from domestic and industrial sources • DEWATS is featured through modular design of all components • Hence it is flexible and allows efficient treatment for organic wastewater flows from 1-1,000 m3 per day • DEWATS systems are tolerant towards inflow fluctuation • Design and construction are long lasting and reliable • DEWTAS do not require sophisticated or costly maintenance • DEWATS can complement conventional treatment systems for more sustainable and effective service
DEWATS :Horizontal flow System DEWATS :Vertical flow System
O&M of DEWATS System The most critical items in which operator intervention is necessary are: • Adjustment of water levels • Maintenance of flow uniformity (inlet and outlet structures) • Management of vegetation • Odor control • Maintenance of berms (walls)
Options for collection and drainage of wastewater – decision tree back todiscussionofcentralizedsystems back todiscussionof de-centralizedsystems source: MoUD, WSP: Technology Options for Urban Sanitation in India – A Guide forDecision Making, September 2008, page 48 43
Good Examples: Decentralized wastewater treatment, Agra • Set-up • Situation • Process • Project implementation: • Preconstruction • Construction • Post construction – O&M throughcommunity • central, high density, lowincomequarter • Lead agency: Centrefor Urban and Rural Excellence (CURE) • Agra MC, USAID and Cities Alliance • approx. 450 HH, 2350 inhab., 85% open defecation • Installation offullyfunctional 5 chamber DEWAT system • Preconstruction: • planning, system design • sitevisits • communityconsultation • identificationofland • approvals • contractingoflocalworkforce • open drainswithwastewater, fecesand HH wastecrossingquarter • nowastecollectionordisposalsystem • Community involvement • decisionmaking • implementationandmonitoring • monetarysupportfortoiletconstruction • sanitationcommittees – including SW collection • empoweringyouthandwomenforincomegeneration • adjacenttoquarter large open drainwithwastewaterfromupstreamsettlements source: http://www.awasla.org/Docs/ACCESS_ahmedabad_case_study.pdf
Good Examples: Decentralized wastewater treatment, Agra • Sustainability • Lessons learnt • health, hygieneandnutrition • Main challenge was togetteapprovalforconstructionofthe DEWAT facility • Infrastructure developmenthastobecombinedwithcommunitydevelopmentandengagDay-to-dayinvolvementofthecommunityisimportasntforlong-term sustainability • socioculturalandinstitutionalaspects • O&M couldbesettledthroughintensecommunityinvolvement • Holisticapproachincludingsanitation, environment ans livelihoodensuredgeneralupgradingofqualityoflife • financialandeconomicissues • DEWAT requirescontinuousflowofwater, dailysupervisionandcleansingisexecutedbythelocalcommunity • environmentandnaturalresources • Involvmentofthecommunityfromtheverybegiiningcreatesownershipandsupportslater O&M and proper functioning • technologyandoperation • Awarenessraisingregardingsanitationis a must forreductionof open defecation source: http://www.awasla.org/Docs/ACCESS_ahmedabad_case_study.pdf
Treatment & disposal Treatment process in centralizedsystems Treatment process in decentralizedsystems Septage treatment Reuse ofresiduals 46
Pre-treatment: • removes the heavy solids to prevent blockages in the following treatments processes • aeriationto allow removal of scum Process Flow Diagram for a typical large-scale two step treatment plant 47 • Primary treatment : • removes organic and inorganic solids by the physical process of sedimentation and floatation. • Pre- and primary treatment are summarized as physical treatment. • Secondary treatment : • removes the dissolved and colloidal organic substances from waste water through microorganisms. • Secondary treatment is known as biological treatment.
What is meant by tertiary treatment? • “Tertiary treatment” is used to improve the quality of treated wastewater so that it can be further utilized (re-use) Whatismeant? Possibleutilization • cleansing water for the treatment plant, • re-use in industrial cleaning processes • gardening • flushing of toilets • cooling water Technology • Mechanical • sand filter • disk filter • active coal filter • micro filter • Chemical • precipitation • flocculation • UV-desinfection, ozonation, Hypochloridation
DEWATS – treatment process schemetakenfrom DEWATS Guidebook, p.35 / 36
Tostabilze septage: • decreasingodours, • reducinglevelsofpathogensand • furtherdecay Septage treatment and disposal raising pH aerationtobiologicallyreduceorganiccompoundsandodour • reductionoforganiccompounds, • productionofmethane, • requiressludgeforco-treatment • mix withbulkingagent, • aerteand turn • processheatdestroyspathogens • possibilityofodours • surfaceapplication • sub-surfaceapplication • burial source: Centrefor Science and Development: Policy Paper on Septage Management in India, May 2011, page 18