北方冬季人工湿地脱氮效果分析

Analysis of nitrogen removal effect of constructed wetland in winter of North China

人工湿地既能净化水质,又能带来良好的生态效益与景观效益,促进水体维持良好状态,经常作为辅助手段解决黑臭水体问题。选取某北方城市河道黑臭水体治理工程中的人工湿地辅助水质提升工程两类人工湿地(潜流湿地与表流湿地)进行分析,两级表流、潜流湿地实际处理水量均为70 m 3/d,植被为芦苇、香蒲,分析其中某一湿地冬季水体氮处理效率,结果表明:冬季潜流湿地整体总氮均有一定的去除率,最高能达到60.68%,最低仅为23.01%,随着时间去除率有一定的波动,总体呈现先升高后降低再升高的状态;总氮均有一定的去除率,最高能达到37.16%,最低仅为17.58%,随着时间去除率有一定的波动,总体呈现升高降低循环式波动的状态。人工湿地在北方冬季可以进行一定脱氮处理,但保温仍然是冬季人工湿地处理污水需要解决的重要问题。冬季植被适当的覆盖能够带来较好的保温效果,提升处理效率,但同时也应注意未收割植物的腐败将去除的氮磷回归到湿地系统中,长此以往也会造成进水水质不稳定。

Constructed wetland can not only purify the water quality,but also bring good ecological and landscape benefits,and promote the water to maintain a good state.It is often used as an auxiliary means to solve the problem of black and smelly water.In this paper,two types of constructed wetlands(subsurface flow wetland and surface flow wetland)were selected as the auxiliary water quality improvement project of constructed wetlands in a river black odor water treatment project in a northern city.The actual water treatment capacity of the two-stage surface flow wetland and the subsurface flow wetland was 70 m 3/d,and the vegetation was reed and cattail.The nitrogen treatment efficiency of water body in winter in one of the wetlands was analyzed.The results showed that the total nitrogen removal rate of the subsurface flow wetland in winter was certain,reaching 60.68%at the highest and 23.01%at the lowest.With the time the removal rate fluctuated,and the total nitrogen removal rate increased first and then decreased and then increased.The removal rate of total nitrogen reached a certain extent,with the highest reaching 37.16%and the lowest only 17.58%.With time,the removal rate fluctuated to a certain extent,and the overall increase and decrease cyclical fluctuations were observed.The artificial wetland can carry out certain denitrification treatment in win in that north.But heat preservation is still an important problem to be solved in winter constructed wetland wastewater treatment.Proper vegetation cover in winter can bring good heat preservation effect and improve treatment efficiency.However,attention should be paid to the corruption of un-harvested plants to return the removed nitrogen and phosphorus to the wetland system,which will cause unstable inlet water quality in the long run.