Technical, economic and environmental feasibility of recycling nutrients in waste in Southern Thailand

Technical, economic and environmental criteria were used to evaluate the feasibility of recycling plant nutrients in kitchen waste, human excreta and sullage from households in Phattalung (urban), Kuan Lang (peri urban) and Prik (rural) in Southern Thailand. The difference in situation and context of the three areas called for individual solutions, and for each area three sanitation systems were evaluated. However, in all three areas recycling human excreta and kitchen waste via composting latrines was found to be more environmental feasible than human excreta managed in septic tanks or sub surface trickle irrigation and kitchen waste disposed of at landfill sites or treated at composting plants. Sullage should in Kuan Lang and Prik be used directly on garden crops, but in Phattalung be treated in waste stabilisation ponds before discharge, to be environmentally feasible. The economic feasibility results varied among the three areas and among the involved stakeholders: farmers and Kuan Lang administration benefited from recycling waste, at the expense of other private users, Phattalung municipality and Prik municipality. The main cause of these conflicting interests was lack of cost recovery and public participation, which should therefore serve as the fundament of any future environmental and economic feasible sanitation system.