Treatment and Re-cycling of Sludge from Urban Decentralized Sanitation Facilities

Decentralized sanitation facilities like pit latrines, conservancy tanks, septic tanks or even decentralized wastewater treatment plants accumulating organic sludge hazardous to ground water resources and public health. Many municipalities around the world are challenged with the collection and environmental disposal of this urban sewage sludge or so called septage. The paper presents the frame condition and challenges of septage disposal in Indonesia and introduces a new treatment system with up to 4 years operational experiences of two running projects. The presented projects are located in Mojokerto (East Java) and in Banda Ache (West Sumatra) and serving a catchment area of more than 100,000 households. The treatment system has been developed by the German NGO BORDA in 2004 as a complementary DEWATS (decentralized wastewater treatment system) component for the disposal and processing of urban septage. The system is modular and the treatment components are compiled according to the project requirements and after 4 years operation has been proven the developed technical conception and features as follows:– Robust and low maintenance requiring system– No electric energy required– It can treat and can be adapted to various types of septage– No or minimal odor emission which allows installation close to residential areas or in industrial areas– Production of sellable fertilizer– Land requirement 60-75 m2 per m3 septage per day– Operational cost 1.5 USD per m3 Facts, experiences and technical designs are presented and explained in the paper.