Control performance of bioretention system on non-point source pollution in typical Chinese rural areas of Southeastern China

Abstract

Current work focused on analysis and implementation and of bioretention system in typical rural areas in Southeastern China. These areas are vigorously protected by the Chinese government due to their traditional farming and architectural characteristics that symbolize ancient Chinese civilization. Bioretention system with high pollutant removal capacity and strong environment adaptability might be a suitable technical solution for controlling non-point source pollution in ancient Chinese villages. In lab-scale study, the hydraulic characteristics of the media and the impacts of depth of media layer, depth of saturated zone (SZ), vegetation and extra carbon source (ECS) on pollutant removal efficiency of bioretention system against the current situation of NSP in typical Chinese rural areas (TCRA) were investigated. The results revealed that roots were conducive to maintain the hydraulic conductivity and pollutant removal efficiency of the filter media. The increasing depth of media layer and SZ, vegetation, and ECS could improve pollutant controlling performance of bioretention system. A field-scale bioretention system with optimal configuration determined by lab-scale study was implemented on the site. The average removal rates of TSS, COD, TN and TP of the bioretention system in field study were 81.34%, 41.88%, 37.33% and 71.64%, respectively. Bioretention system could combine with nearby farmland in rural areas without disturbing their original texture, furthermore, proper maintenance and replacement of media and vegetation could significantly improve the performance of bioretention system in TCRAs.