植物和基质在生态浮床去除农村地表径流氮磷中的作用

Role of plants and substrates in floating treatment wetlands on nitrogen and phosphorus removal from rural surface runoff

为探究植物和基质在生态浮床去除农村地表径流氮磷中的作用,设置2个污染物浓度水平并构建4组实验进行对比.结果表明,植物和基质均能强化生态浮床对水中不同形态氮磷的去除.植物和基质使NH~+-N去除率分别提高17.7%~28.1%和21.9%~43.6%.高、低浓度下,基质使总磷(TP)去除率分别提高33.0%和1.9%,而植物使TP去除率分别提高40.5%和18.0%.植物对溶解态活性磷(SRP)的去除较基质更稳定.植物根系及基质强化了微生物介导的溶解态非活性磷(SNRP)的转化.高浓度下植物和基质的组合表现出稳定且高效的脱氮除磷性能,而低浓度下植物的氮磷去除率优于基质.此外,割茬短暂降低了植物对氮磷的去除率.综上,耦合植物和基质的组合式生态浮床有较高的水质适应性,适于农村地表径流的原位处理.

To study the role of plants and substrates in floating treatment wetland(FTW)on nitrogen andp hosphorus removal from rural surface runoff,a comparative experiment was conducted by setting two concen-t ration levels and constructing four groups. The results show that plants and substrates are effective for the removal of different forms of nitrogen and phosphorus in FTW. The removal rate of NH-N is increased by 17.7% to 28.1% and 21.9% to 43.6% by plants and substrates,respectively. The removal rate of totalp hosphorus(TP)is increased by 33.0% and1.9% by substrates at high and low concentrations,while the re-m oval rate of TP is increased by 40.5% and 18.0% by plants at high and low concentrations. The removal ofs oluble reactive phosphorus(SRP)by plants is more stable than that by substrates. Plant roots and substratese nhance the microbial-mediated transformation of soluble nonreactive phosphorus(SNRP). The combinationo f plants and substrates shows stable and efficient nitrogen and phosphorus removal performance with high concentration treatment,while the nitrogen and phosphorus removal efficiency of the plant is better than that of thes ubstrate at the low concentrations. In addition,the plant harvesting temporarily reduces the removal efficiencyo f nitrogen and phosphorus. In conclusion,the combined FTW with plants and substrates is suitable for in-situt reatment of rural surface runoff due to its high adaptability to water quality.