Effective faecal sludge management measures for on-site sanitation systems

Most cities of developing countries in Asia and Africa still employ on-site sanitation systems such as septic tanks or cesspools to treat toilet wastewaters. The septic tank sludge or faecal sludge (FS) which is highly polluted needs to be periodically removed for further treatment and disposal/reuse. However, due to lack of capital, appropriate technologies and management policies, faecal sludge management (FSM) in several cities has been found to be unsatisfactory, causing environmental pollution and health problems. This study aimed to evaluate existing FSM practices, their strengths and weaknesses, and develop FSM indicators responsible for FSM practices which were: collection efficiency, treatment efficiency, benefit/cost ratio and social satisfaction. Based on data collected from 50 cities in Thailand, factors influencing the efficiency of the FSM indicators were identified and simulated using Response Surface Methodology (RSM). An FSM effectiveness diagram was developed and tested with actual data of four cities in Asia having different FSM efficiencies. The findings identified the influencing factors affecting the FSM efficiencies of these tested cities and proposed effective measures for improving FSM practices. The effective FSM measures, as proposed, are recommended for implementation by various cities to minimize environmental pollution and protect public health.