改良填料折流式生物滞留系统对雨水中氮磷削减的效果

针对生物滞留池对雨水中氮、磷去除效果不稳定，甚至出现负去除现象，开展改良生物滞留系统的研究。通过构建直流式和折流式2种生物滞留系统，分别填充传统填料和羟基铝蛭石污泥颗粒（HAVSP）改良填料，搭建传统填料直流式生物滞留柱（1^#）、改良填料直流式生物滞留柱（2^#）、改良填料折流式生物滞留柱（3^#）3个模拟试验柱；比较了3个模拟试验柱对雨水中氮、磷的去除效果，并探讨了HAVSP对生物滞留填料的改良作用。结果表明：HAVSP改良填料折流式生物滞留系统对氮、磷的削减效果比传统填料和改良填料直流式生物滞留系统更加明显，且在350 mm淹没出流高度时对氮、磷削减效果最佳，总氮和硝态氮去除率最高可达76%和77%。

Effect of amended filler fold-flow bioretention system on nitrogen and phosphorus reduction in rainwater

The study on the amended bioretention systems was conducted in view of the instability and even the negative removal of N, P in rainwater by the bioretention tanks. By constructing two systems of straight-flow and fold-flow bioretention, traditional fillers and hydroxy-aluminium vermiculite sludge particle (HAVSP) were filled respectively. Three simulation test device columns were set up, of which 1# was a traditional filling straight-flow bioretention column, 2# was a modified filling straight-flow bioretention column, and 3# was a modified filling fold-flow bioretention column. The removal effect of nitrogen and phosphorus in rainwater under three simulated experimental devices was compared, and the improvement effect of HAVSP on bioretention filler was discussed. The results showed that the reduction effect of nitrogen and phosphorus in HAVSP amended filler fold-flow bioretention system was more obvious than that in conventional filler and amended filler straight-flow bioretention system, and had the best effect on nitrogen and phosphorus reduction when the outflow height was 350 mm, with total nitrogen and nitrate-nitrogen removal rates up to 76% and 77%, respectively.