Removal Effect of Two Macrophytes of Constructed Wetland to Domestic Sewage

Removal effect of macrophytes of constructed wetland to domestic sewage remain poorly understood,taking Iris pseudacorus and Canna indicaas materials,using constructed wetland without macrophyte as CK,comprehensive analysis was present based on constructed wetlands with two macrophytes and without macrophyte,and removal effect of total nitrogen(TN),total phosphorus(TP),ammonia nitrogen(NH4-N)and chemical oxygen consumption(COD)in domestic sewage were compared.The results showed that constructed wetlands had obvious removal effect which was significantly higher on COD.Removal effect of constructed wetland with macrophytes was higher than constructed wetland without macrophytes on TN,TP,NH4-N and COD,and the removal rates were consistent with constructed wetland period which was highest in stable period,and then the removal rate gradually decline and leveled off after stable period.The removal rate of TN,NH4-N and COD was unimodal curve along constructed wetland period,and the removal rate of TP was leveled off and then decline along with constructed wetland period.The finding suggests that macrophytes of constructed wetland could effectively promote pollutants,and there were some differences in different periods of constructed wetland between macrophytes removal effect,but there was a different between macrophytes,and the removal efficiency of Canna indica was obviously higher than that of Iris pseudacorus,and the contribution on TN,NH4-N and COD removal rates were 40.37%,39.08%,42.75%,41.93%and 26.06%,30.56%,30.38%,31.86%,respectively.