Effect on constructed wetland for pond aquaculture wastewater treatment at Shatianhu in Qingpu,Shanghai

For reducing the pollution effect on the surround waters,surface and subsurface flow constructed wetlands were utilized to effectively treat the pond aquaculture wastewater of Shatianhu in Qingpu,Shanghai.With wetland purification treatment,the concentrations of TN,TP,CODMn,and NH4-N of aquaculture wastewater were dropped from 2.32,0.50,14.88,0.61 mg/L,to 0.98,0.18,9.72,0.30 mg/L respectively,chlorophyll a from 369.6 μg/L to 61.78 μg/L.The water quality of the aquaculture wastewater was efficiently purified.It was found that the contents of nitrogen and phosphorous in alive wetland plants were obviously higher than those in the dead.Nitrogen concentration measured in dead Pontederia cordata,Iris pseudacorus,Typha minima were respectively 18.8%,26.8% and 38.1% of that measured in alive.Harvesting the wetland plants in dead can remove nitrogen and phosphorus 11.68 g/m2and 4.81 g/m2respectively.Thalia dealbata has the highest nitrogen and phosphorous removal capacity.Harvesting wetlands plants prior to their death can improve the purification effect of plants absorption purification in the entire wetlands system.