MIT OpenCourseWare http ocw mit edu 11 479J 1 851J Water and Sanitation Infrastructure in Developing Countries Spring 2007 For information about citing these materials or our Terms of Use visit http ocw mit edu terms On site Sanitation Brian Robinson and Susan Murcott Week 12 MIT 11 479J 1 851J Water and Sanitation Infrastructure in Developing Countries Mass Institute of Technology May 8 2007 On site Sanitation Sanitation ladder options in sanitation Ecological Sanitation Case Study Ecosan in Kenya Improved sanitation connection to a public sewer connection to septic system pour flush latrine simple pit latrine ventilated improved pit latrine The excreta disposal system is considered adequate if it is private or shared but not public and if it hygienically separates human excreta from human contact Not improved service or bucket latrines where excreta are manually removed public latrines latrines with an open pit Sanitation Ladder Technology Hygiene 1 2 3 4 5 6 7 Open defecation flying toilet Cathole burial Pit latrine VIP EcoSan Pour flush Water sealed toilets neighborhood wastewater collection 8 Water sealed toilets neighborhood wastewater collection treatment 1 No sanitation S Murcott Poop T P 2 Cathole burial Sanitation Ladder Technology Hygiene 1 2 3 4 5 6 7 Open defecation flying toilet Cathole burial Pit latrine VIP On site sanitation EcoSan Pour flush Water sealed toilets neighborhood wastewater collection 8 Water sealed toilets neighborhood wastewater collection treatment 3 Pit latrine with pit Drainage 3 Pit Latrine No Pit 4 Ventilated improved pit latrine VIP Fly screen Air ventilation Vent pipe Seat cover A dry latrine system with a screened vent pipe to trap flies and often with double pits to allow use on a permanent rotating basis Considered a safe hygienic means of excreta disposal Pedestal Cover slab Pit collar May be extended to base of pit in poor ground conditions Hand dug or mechanically dug pit Figure by MIT OpenCourseWare http web mit edu urbanupgrading VIP Latrine S Murcott All those fill up Vac U Pump is one solution but Cost of pumping Physical space for tractor pump Who s responsible Need pits structured vaults 5 Ecological Sanitation Ecosan refers to the on plot handling with or without urine separation of excreta with minimal use of water so that urine nutrients and sanitized biomass are the end products http web mit edu urbanupgrading Fly screen Air ventilation Vent pipe Seat cover Access cover Pedestal Urine diversion Urine outlet pipe to soakaway or collection pot Turning and removal of composted material by hand Figure by MIT OpenCourseWare S Murcott 5 Ecological Sanitation How Does It Work Decomposition by Dehydration Dry sanitation 20 moisture Addition of ash soil or lime Residence time 6 12 months OR Decomposition by Composting Pathogen destruction by aerobic microbial activity Temperatures 60 C Proper moisture content C N ratio pH 5 Ecosan in Kenya Ecological Sanitation Composition of Excreta Urine Feces 88 12 Phosphorus 67 33 Potassium 71 29 Wet Weight 90 10 Nitrogen Adapted from Sida 1997 Sanitation Ladder Technology Hygiene 1 2 3 4 5 6 7 Open defecation flying toilet Cathole burial Pit latrine VIP EcoSan Pour flush Water sealed toilets neighborhood wastewater collection 8 Water sealed toilets neighborhood wastewater collection treatment Waterborne options 6 Pour flush toilet Pour to flush But then where does it go 7 8 Septic tank and soakaway or small bore solid free sewer To river Tertiary treatment Secondary treatment Primary treatment Inlet works Wastewater treatment works Full flush toilet Access cover Water trap Scum To option A or B Liquid Sludge Small bore sewer to main sewer in road B A Soakaway Septic tank soakpit or drainage trench Figure by MIT OpenCourseWare S Murcott Potential confounder for flush systems Open Drainage Treatment Methods Treatment Site Facility Type Pit latrine VIP Pour flush Water sealed Community Onsite Offsite Septic WW treatment Septic WW treatment Septic WW treatment Reuse Treatment Management Options Onsite Treatment Options Pit composting EcoSan aquaprivy septic Offsite Treatment Options Stabilization ponds Night soil treatment ponds bucket cartage wetlands drainfields wastewater treatment facilities Demand Management Options Conservation point of use controls demand elimination Reuse Treatment Options Biogas Thermophilic aerobic composting Mesophilic anaerobic composting Teku Septage Treatment Plant Greywater Recovery Constructed wetlands Demand Management Voluntary conservation Flow restricting fixtures and aerators Water conserving appliances Low flow toilets or tank displacement systems Drip bleed irrigation distribution systems Demand Management Point of use Controls Automatic shutoff controls Water fuses Thermal bleed systems Instantaneous hot water heaters Timed or moisturebased irrigation control systems Eliminating Demand Water free toilets urinals Leak repair Xeriscaping Ozonated laundering Figure by MIT OpenCourseWare Institutional community capacity issues What community involvement cleanup options are there How organized is the community What level of maintenance involvement is the community willing to take Level of agriculture and household income is there any demand for reuse Community Wealth Community Factors that affect sanitation options Municipalmaintained Waterborne Sewerage Communitymaintained condominial Sewers Onsite Sanitation options Community Organization maintenance required Ecological Sanitation Industrialized Sanitation Linear Flow Images removed due to copyright restrictions a straight line arrow goes from a sewer outfall to a wastewater treatment plant to a body of water where effluent is discharged Ecological Sanitation Closed Loop Images removed due to copyright restrictions two arrows in a loop connecting a drawing of an outhouse crop fields fertilized with human waste and fully grown corn Definition of ecosan Any sanitation system that reuses the water and nutrients in human excreta or domestic wastewater is considered ecological sanitation Application of ecosan and ecosan literature typically focuses on low tech recycling toilets Courtesy of the Deutsche Gesellschaft f r Technische Zusammenarbeit GTZ Used with permission Courtesy of the Deutsche Gesellschaft f r Technische Zusammenarbeit GTZ Used with permission Courtesy of the Deutsche Gesellschaft f r Technische Zusammenarbeit GTZ Used with permission Courtesy of the Deutsche Gesellschaft f r Technische