Feasibility of anaerobic sewage treatment in sanitation strategies in developing countries

This desk study was written at the request of the Dutch Directorate-General for International Cooperation (DGIS) to assess the feasibility of the anaerobic high-rate treatment of domestic sewage in urban areas of developing countries. It is primarily based on information from DGIS-funded research projects in Colombia, Indonesia and India, where Upflow Anaerobic Sludge Blanket (UASB) reactors were investigated. After an introductory chapter on wastewater treatment technologies, sanitation feasibility strategies and selection criteria for wastewater treatment technology are presented. This is followed by a description of the pros and cons of anaerobic treatment technology for domestic sewage. Data from five demonstration plants in Indonesia, Colombia and India are reviewed. The feasibility of anaerobic treatment in economic, financial and social terms, is evaluated for three options: on-site treatment (household scale); centralized off-site treatment (city-wide); and intermediate scale or township level treatment. An overview of wastewater treatment technologies is given in an appendix. A second appendix provides basic principles for the economic and financial assessment of sanitation projects.