Removal efficiency of phosphorus using constructed pond-wetland system to purify reclaimed water under different hydraulic loadings
不同水力负荷下塘-湿地组合处理系统对再生水磷的净化效果

This work investigated the removal efficiency of total phosphorus(TP) and soluble reactive phosphorus(SRP) in a constructed pond-wetland combination system,which was applied to polish the effluent from a membrane bioreactor(MBR) treating the wastewater in Tianjin Airport Industrial Park for the purpose of reclamation.Results indicated that the MBR effluent had a relatively high SRP concentration with a SRP/TP ratio reaching 84%.Under three different hydraulic loadings(i.e.,100,150 and 200 m3/d),the pond-wetland system always exhibited good efficiency on phosphorus removal.The concentrations of TP and SRP were reduced from 1.64 to 0.36 mg/L and 1.30 to 0.28 mg/L,respectively.The corresponding SRP/TP ratio was decreased from 84% to 54.5%,indicating a significant removal of SRP.It is seen that the problem of high SRP concentration in the MBR effluent can be well settled by the pond-wetland system,thus greatly alleviating the potential risk of algal blooms when the reclaimed wastewater is used for landscape water.