城市绿地对雨水径流污染物的削减作用

Reduction functions of runoff contaminants by the urban greenbelt

采用模拟城市绿地和降雨系统装置研究城市绿地对径流雨水污染物的削减作用,通过对降雨过程及降雨后装置内土壤微生物数量、生化作用强度及土壤性质的分析,初步研究了城市绿地对雨水径流污染物的削减作用机理.结果表明:在2h的降雨过程中模拟绿地对雨水中COD_(Cr)、氨氮、硝态氮、总氮和总磷的平均削减率分别为41.3%,44.1%,38.5%,38.2%和39.0%.随着降雨时间的延长,削减率逐渐降低.绿地系统对径流污染物的去除是生物与非生物共同作用的结果.在降雨过程中污染物的去除主要依靠土壤及植物根系的吸附、过滤和截流作用,降雨后的5～8d内土壤微生物的生化作用最强,并且土壤有机质、总氮和总磷含量逐渐降低,主要进行的是微生物对吸附于土壤颗粒表面的污染物的分解作用.两周后总氮和有机质在土壤中还有一定的累积,总磷含量基本达到降雨前的水平.

In this paper,an artificial greenbelt and a lab-scale rainfall device were used to study the pollutant removal mechanisms of stromwater runoff through urban greenbelt. The results showed that,it was the cooperation of biological and abiological actions that caused the reduction of runoff contaminants. The average removal efficiencies of COD, NH4^＋-N, NO3^--N, TN and TP were 41.3% ,44. 1% ,38.5% ,38.2% and 39.0% respectively. Soil adsorption actions play the most important role during the rainfall, and microbial degradation mainly operates from the 5th day to the 8th day after rainfall. About in two weeks,COD,NH4^＋-N,NO3^-N,TN and TP were basically removed and the soil were restored for next rainfall.