2种改良土壤渗滤系统对降雨径流中氮的去除

为研究改良土壤渗滤系统对降雨径流中不同形态氮(NH4+-N,NO3--N,NO2--N,TN)的去除效果及径流中氮负荷对氮去除率的影响,实验分别以聚氨酯泡沫和人工草皮为改良材料,以降雨径流中的氮为处理对象进行室内模拟研究。结果表明,聚氨酯泡沫土壤渗滤系统及草皮土壤渗滤系统对TN,NH4+-N均具有较好的净化效果,并表现出良好的耐冲击负荷能力。TN平均去除率分别为72.65%和71.07%,NH4+-N平均去除率分别为98.10%和99.09%。2种渗滤系统对NO3--N去除效果均较差,表现为-420.07%和-171.66%的负去除率。聚氨酯泡沫土壤渗滤系统对NO2--N的平均去除率为87.29%,高于草皮土壤渗滤系统53.77%的平均去除率。总体上,聚氨酯泡沫土壤渗滤系统对径流中氮的去除效果优于草皮土壤渗滤系统,具有较好的应用前景。

Nitrogen removal from runoff by two kinds of improved soil infiltration systems

The objective of this study was to evaluate the removal of TN, NH4+-N, NO3--N and NO2--N in stormwater runoff using two soil infiltration systems which were improved by polyurethane foam and artificial turf, respectively. Influence of pollution load on nitrogen removal rates was also considered. Experiments were conducted employing lab-scale improved soil infiltration systems. The result showed that TN and NH4+-N were removed efficiently by both polyurethane foam and artificial turf soil infiltration system, and the systems had powerful resistance to shock load. TN removal rates were 72.65% and 71.07%, and NH4+-N removal rates were 98.10% and 99.09%, respectively. Both improved soil infiltration systems presented bad performance in the NO3--N removal with negative removal rates of -420.07% and -171.66%. The average NO2--N removal rate in polyurethane foam soil infiltration system was 87.29% which was higher than the value of 53.77% in artificial turf soil infiltration system. On the whole, polyurethane foam soil infiltration system performs better than artificial turf soil infiltration system in removal of nitrogen in stormwater runoff and has a better application future.