Application of analytic hierarchy process in comprehensive evaluation of decentralized domestic wastewater treatment in small town

A comprehensive evaluation system, including 4 layer, 11 indexes and 6 schemes, for domestic wastewater treatment in small town adaptive to the decentralized condition of China is established by adopting the analytic hierarchy process. In the evaluation system the technology of constructed wetlands, stabilization ponds, slow rate land treatment system, rapid infiltration system, subsurface infiltration system and overland flow system are evaluated from the view points of technical performance, economic benefit and management benefit to determine the optimal scheme. At the same time, the method of expert's evaluation is also adopted to evaluate these technologies. The calculation result shows that the constructed wetland has the highest score expressing the preferred technology for decentralized domestic waste water treatment in China's small town.