Optimization of rural domestic sewage treatment mode based on life cycle assessment method: A case study of Wuzhong District, Suzhou City, China

Optimizing the spatial layout of sewage treatment facilities and establishing a comprehensive benefit assessment system are imperative for improving the scientific decision-making process of rural sewage treatment modes (RSTMs) in developing countries. Based on the k-means clustering algorithm incorporating population and elevation factors, life cycle theory, and the weighted sum multi-objective optimization approach, this study developed an RSTM evaluation framework to provide spatial layout alternatives and comprehensive environmental-economic benefit assessments. Taking Wuzhong District in Suzhou, China, as an example, the results showed that the improved k-means clustering algorithm enabled the proper distribution of sewage treatment facilities to be established in villages with low elevation and a concentrated population, with a reasonable spatial layout. The entire environmental impact potential and economic cost trends of different RSTMs initially decreased before rising with the increase in facilities. These trends indicated that when facility layouts were too centralized or too decentralized, the environmental impact potential and economic cost increased. Additionally, when environmental impact is a priority factor, more facilities should be built. Alternatively, if economic factors are considered a priority, it is preferable to centralize the domestic treatment in neighboring villages and construct fewer facilities.