Selecting appropriate treatment technologies for faecal sludge (FS) from onsite sanitation systems

Context Worldwide: FS production much larger than treated volumes In Vietnam: • Urban households required to own septic tanks • Combined onsite and centralized sanitation • FS emptying frequency up to 10 years or more Negligible FS volumes treated before discharge PURR: Partnership for Urban Resource Recovery • Developing knowledge for adequate FS treatment in urban Vietnam • Testing feasibility of anaerobic digestion for FS treatment Study goal To understand the local context and factors influencing the selection of appropriate FS treatment technologies in case study cities in Vietnam Methods Field visits in 5 cities Review of literature and legal documents Interviews with local authorities and stakeholders in charge of wastes and FS Household surveys in sewered / non-sewered, poor and rich areas (100 houses per city) Results • 73% septic tanks have less than 5 years and need to be emptied within 5 to 15 years (emptying frequency in 5 case study cities >10 years) ->FS will continue to be produced in urban Vietnam and strategies are required in short term • A variety of stakeholders and management systems exist between cities with a lack of willingness to manage FS ->Need for a coherent sanitation strategy at the national level, with geographical separation of areas with onsite/centralized systems • Different waste management infrastructures exist in each city ->Different technologies are required, even in the same country Conclusions and perspectives • Current engineering approaches and sectorial strategies are not adequate • Comprehensive context assessment is required • Possibilities for co-treatment of organic wastes with FS to optimize financial flows, public and environmental protection will be assessed