聚丙烯球对表面流人工湿地氮磷时空分布的影响

Effect of Polypropylene Pellets on the Temporal and Spatial Distribution of Nitrogen and Phosphorus in Surface Wetland

为探讨聚丙烯球对表面流人工湿地内氮、磷时间和空间分布的影响,文章采用室外对照实验的方法,构建了表面流湿地-聚丙烯球组合装置(系统A)、表面流湿地(系统B)、聚丙烯球装置(系统C)及空白对照4套平行小试装置,对4套装置3个不同水层高度氮、磷时间和空间降解规律进行研究。结果表明:引进聚丙烯球的表面流人工湿地(系统A)的NH4+-N、TN、TP去除效果均优于其余3个系统;系统A最高的氮磷去除率发生在第0~3天,第6天氮磷出水浓度即可达到地表水Ⅲ类标准,而没放置聚丙烯球的系统B则需要第9天才达到地表水Ⅲ类标准。因聚丙烯球微生物挂膜,系统A的上、中、下水层NH4+-N、TN、TP浓度均低于其余3个系统。时间上,聚丙烯球通过提高氮磷去除效率来影响表面流人工湿地氮磷在时间上的分布;空间上,聚丙烯球通过增加水层中的微生物量来促进不同水层氮磷的去除,对上水层的促进作用最明显。

To investigate the effect of polypropylene pellets on the temporal and spatial distribution of nitrogen and phosphorus in free water surface constructed wetland,an outdoor experimental control method was used.Four parallel units of pilotscale constructed wetlands were built,and they are free water surface constructed wetland with polypropylene pellets(System A),free water surface constructed wetland(System B),only polypropylene pellets(System C)and blank control,respectively.The nitrogen,phosphorus temporal and spatial degradation of three different water layers in four systems were studied.Results showed that the removal efficiency of NH4+-N,TN and TP in the surface-flow constructed wetland(System A)with polypropylene pellets were best in all systems;the most efficient nitrogen and phosphorus removal of System A occurred in days 0-3,the surface water III standard can be reached on the 6thday,while the System B without the polypropylene pellets reached the surface water III standard on the 9thday.The mass concentration of NH4+-N,TN and TP in the upper,middle and lower water layers of System A was lower than that of the other three systems due to the exist of microbial membrane of polypropylene pellets.In temporally,polypropylene pellets affect the distribution of nitrogen and phosphorus in surface-flow constructed wetlands by increasing the efficiency of nitrogen and phosphorus removal;spatially,polypropylene pellets promoted the removal of nitrogen and phosphorus in different water layers by increasing the amounts of microorganisms in the water layer.The promotion of the upper water layer is most obvious.