自然坑塘对夏季降雨径流污染的截流净化效果

选取上海市临港新城4种不同类型的自然坑塘,比较其在夏季对降雨径流污染的截留效应以及水质净化效果。结果表明:场地主要降雨径流污染物为TN、COD,自然坑塘对降雨径流污染具有较好的截留效应,但自然坑塘的截流效率并未得到最大程度的发挥。自然坑塘对于水质的净化处理效果总体较好,研究期内4个自然坑塘的TP平均净化率分别为:46.4%、4.6%、57.6%、57.4%;TN平均净化率分别为:34.7%、40.7%、46.4%、26.9%;COD平均净化率分别为:21.6%、40.5%、47.3%、-4.3%。在高温少雨、水深过浅的情况下,自然坑塘易出现水华现象,影响水质净化效果。因此,需要对自然坑塘进行优化设计、改造,保持自然坑塘生态系统的稳定与自我更新能力,才能最大限度地发挥其对于城市雨洪调蓄、径流污染控制等方面的综合生态价值。

Retention and Purification of Pollution from Summer Rainfall Runoff Using Natural Ponds

To study the effectiveness of pollution retention and purification of different ponds in Shanghai Lingang New City during summer season,an in situ investigation was conducted.Findings of the study showed that in general natural ponds could retain and remove pollutants in rainfall runoff with effect in terms of TN,TP and COD,and removals of TP,TN and COD were obtained based on in situ water sampling and analysis for four ponds.The study also found that on the occasion of higher temperature and less rainfall and lower water level phytoplankton blooms often took place in some of the ponds resulting in reduced purification capabilities of the ponds.Thus the natural ponds still have potential to extend their pollution retention and purification capabilities on condition that natural ponds would be remolded and optimized designed to set up their stability of ecosystem and abilities of self-renewal.