Rural domestic sewage treatment in Northeast cold region of China: rational evaluation of technology options

This research aims to propose reasonable solutions for reference based on the characteristics of rural domestic sewage of the cold regions in Northeast of China (CRNC). Analytical hierarchy process (AHP) and fuzzy comprehensive evaluation (FCE) are used to analyze and calculate the weight of rural domestic sewage treatment indicators in the cold northeast area. The AHP method is used to optimize and calculate the CRNC's rural domestic sewage treatment indicators, and obtain the comprehensive weights of 15 indicators in the three standard layers and the indicator layer. It further analyzes the weight of the secondary indicators to determine the standard of the evaluation indicators. The FCE method is used to calculate the fuzzy measure and membership degree. Finally, AHP weighted summation is used to determine the applicability of the technical choice. The calculation results determine the best technology combination scheme of the three processing methods: (1) sequential batch reactor = 0.820, constructed rapid infiltration = 0.701; (2) soil infiltration technology = 0.803, stable pond technology = 0.585; (3) constructed wetland treatment technology = 0.787, septic tank technology = 0.585. Schemes 1, 2, and 3 are used for centralized treatment mode, decentralized treatment mode, and treatment mode for water environment sensitive areas, respectively. The research results provide good theoretical support for the technical selection of different treatment modes in cold regions.