溶解氧对人工湿地处理受污染城市河流水体效果的影响

研究了溶解氧在人工湿地中的分布对受污染城市河流水体处理效果的影响规律及其意义,为城市受污染景观水体处理或雨水处理人工湿地的工程设计提供有效的自然复氧估算方法和设置措施.结果表明,由于自然复氧不利引起的溶解氧不足(<2 mg/L)是导致人工湿地出水水质恶化的主要原因.自然跌水是一种有效的人工湿地充氧方式,其充氧效果可用氧亏比r根据水温、水质以及充氧形式等外部条件参数进行估算.推流态的湿地床内,溶解氧分布与生物量分布以及有机物的去除规律呈现明显的相关性,而对TP沿程去除速率影响不大.设置多级多段跌水有利于均衡湿地床填料内的溶解氧分布,促进硝化反应,保证出水水质.

Effect of DO Distribution on Contaminated Urban Stream Water Treatment Performance in Constructed Wetland

We evaluated the effect of dissolved oxygen(DO) on the performance of two pilot-scale constructed wetlands in treating contaminated water from an urban stream.The aim of this study was to investigate a more effective DO distribution in contaminated stream water treatment wetland that may aid future constructed wetland design effort.The results show poor natural aeration condition and inadequate DO in wetland directly result in the deterioration of effluent water quality.Natural waterfall is an effective aeration way and can improve DO concentration in wetland.The aeration capability of waterfall can be evaluated by oxygen deficit ratio(the ratio of difference between concentration of saturated DO and DO measured before and after waterfall).The distributions of DO obviously correlated with the quantity distribution of microorganism and removal rate of organic contaminants in wetland,however there was no obvious relationship between DO and TP removal rate.Results of the study also indicate setting multi-waterfall in plug-flow wetland can balance the distribution of DO and improve the nitrification.