长江口南汇潮滩湿地污水处理系统的净化功能

Purification Function of Wetland Wastewater Treatment System at Nanhui Beach,Estuary of the Yangtze River

2002年8月～12月对长江口南汇潮滩湿地处理系统对污水净化效果进行了研究,分析了潮滩沉积物中N、P含量变化及其与功能细菌含量间的关系,以及芦苇对污染物质的直接去除作用。结果表明:潮滩湿地对污水的净化效果显著,对TN、TP和COD的去除率分别达到94.06%,76.82%和92.47%;沉积物中N、P含量随样点与排污口间距离增大呈下降趋势;沉积物中NH4+—N、NO3-—N、DIP含量与功能细菌数量间呈良好的正相关;收割芦苇去除的N、P量分别只占全年排入湿地总量的2.201×10-5%、4.552×10-4%。潮滩湿地对污染物的去除主要通过:潮汐稀释转移,沉降,滩面沉积物吸附等物理过程和微生物分解等生物过程的综合作用,而潮滩植物的直接去除作用仅占很小部分。

Purification effects of coastal wetland to wastewater were studied during August to December 2002 at Nanhui Beach, Estuary of the Yangtze River. Concentration variation of nitrogen and phosphorus and relationship to corresponding functional bacteria content in the sediment, as well as the directly removal of pollution of Phragmites australis harvesting were analyzed. Results showed the wetland purification effect to wastewater was distinct, and purification efficiency to TN, TP and COD in wastewater were 94.06%, 76.82% and 92.47% respectively; the nitrogen and phosphorus concentration in sediment declined with the distance to the increased outfall; NH_4^+-N,NO_3^--N and dissolved inorganic phosphorus in the sediment have mostly positive relationship with corresponding functional bacteria amount. The directly nitrogen and phosphorus removal by P. australis harvesting only account for 2.201×10^(-5)% TN and 4.552×10^(-4)% TP of annual inflow to the wetland. Wastewater purification in the beach wetland includes physical process such as dilution and removal by tide, sedimentation, sediment adsorption and biological process as microorganism decomposing. The directly removal effect of beach vegetation is very limited.