Constructing the ecological sanitation: a review on technology and methods

Abstract Wastewater often contains valuable resources (e.g. organic matter and nutrients). Different from conventional sanitation approaches, the ecological sanitation (Eco-San) system is based on the closure of material flow cycles to recover resources with minimized demands on other resources. The review comprehensively summarized the main components of the Eco-San system (user interface, collection and conveyance, storage and primary treatment, and reuse/disposal), the frequently-used evaluation methods, and the framework of evaluation index system. Some typical practical cases were discussed to demonstrate the managerial implications and popularize the applications of the Eco-San system. The results show that the Eco-San systems are beneficial to resource efficiency, agricultural use of the organic matters and nutrients, and energy recovery although some shortages exist (e.g. high cost, cultural constraints, and complex operation and management). The evaluation methods can help to identify the restriction factors, contributing factors and measures to improve the efficiency of the future Eco-San system. The setting, selection and quantification are three critical steps when using the evaluation indices to complete the evaluation process. This study not only provides the methods for both developing novel Eco-San systems (combinations of the components) and improving the Eco-San systems (evaluation of the combinations) to solve the wastewater problem in rural areas. Considering the challenges or limitations in the Eco-San research, the recommendations for future research may mainly focus on the combination of different components, methods for sustainability assessment, quantification of the evaluation index, and implementation of more real Eco-San cases.