不同植物栽种方式对生物滞留系统污染物去除的影响

Effects of different plant cultivation methods on pollutant removal in bioretention systems

为了解植物种类及栽种方式对生物滞留系统污染物去除效率的影响,选取了4种重庆市本土植物,通过单独栽种及两两混合栽种方式,构建雨水生物滞留系统,评估所有生物滞留系统对常见污染物的去除效果。结果表明,栽种植物后系统可有效去除氮素和COD,系统对TN、NH_(4)^(+)-N平均去除率存在差异,范围为61.4%~73.9%,81.5%~85.8%,COD平均去除率差异不明显,范围为66.8%~69.3%。由于基质并未饱和,植物的存在对TP去除效果并无明显提升。与去除率最高的栽种单种植物的系统对比,混合栽种植物的系统在COD和氮的去除上更容易出现超产现象。由于混合栽种增强了COD和氮的去除效果,建议将植物多样性纳入生物滞留系统设计中。

In order to better understand the impact of plant species and diversity on the removal efficiency of pollutants in bioretention systems,four species of native plants were selected for the experiment in Chongqing,and constructed a rainwater bioretention system by planting them individually or in pairs.The removal effectiveness of bioretention systems for common contaminants was detected.The results showed that the planting system could effectively remove nitrogen and COD,and there were differences in the average removal rates of TN and NH+4-N,ranging from 61.4%to 73.9%,81.5%to 85.8%,and the difference in the average removal rate of COD was not obvious,ranging from 66.8%to 69.3%;the presence of plants did not significantly improve TP removal,because the substrate was not saturated.Compared with the single plant system with the highest removal rate,the mixed plant system was more prone to overproduction in nitrogen and COD removal.Since mixed planting enhances removal of organic matter and nitrogen,it is recommended to incorporate plant diversity into the design of bioretention systems.