Removal effect of ecological ditches on agricultural non-point source pollutants in Zhejiang Province
[Objective]This study is to comprehensively evaluate the role of ecological ditches in the blocking process of agricultural non-point source pollution and scientifically assess the effect of ecological ditches on pollutant removal.[Method]6 ecological ditches in Tonglu,Lin'an,Jiande,Dongyang,Yiwu,and Zhuji in Zhejiang Province were selected for water quality monitoring.The removal rates of major agricultural non-point source pollution by ecological ditches were calculated,including total nitrogen(TN),ammonium nitrogen(NH4+-N),total phosphorus(TP),and chemical oxygen demand(COD),and the impact of ditch construction composition on the removal of agricultural non-point source pollution was analyzed.[Result]The average removal rates of TN,NH4+-N,TP,and COD in the 6 ditches were 18.31％,38.74％,13.49％,and 23.97％,respectively,among which the removal effect of NH4+-N was better.The slope roughness of Yiwu ditch and Tonglu ditch was increased by ecological slope construction.The contact area between water flow and slope was increased by narrow ditch width and the retention time of water flow was prolonged.The removal effect of TN and NH4-N was relatively high,and the relationship was linear with the inflow load(P＜0.05).The plant density in Zhuji ditch was high,showing good TP removal effect.The number of denitrification phosphorus removal devices had a good positive correlation with TN,NH4+-N,TP,and COD(P＜0.05),which was a key factor for ecological ditches to intercept agricultural non-point source pollution.[Conclusion]The water purification function of ecological ditches in Zhejiang Province can be strengthened by constructing ecological slopes,installing denitrification phosphorus removal devices,and increasing plant density.[Ch,4 fig.2 tab.34 ref.]
ecological ditchagricultural non-point source pollutionecological slopedenitrification phosphorus removal devicesplant density
万方数据
维普
