5. Conclusions
Water spinach floating bed was used to improve the aquaculture wastewater quality in Songjiang Modern Agricultural Ecological Park, Shanghai, China. The pollution intensity of pond in the present study was higher than that of general aquaculture pond in Shanghai City. After operating for a period of defined time by water spinach floating bed, significant improvement in the aquaculture water quality at experimental site was recorded with average removal rates of TN, NH4+-N, NO2−-N and TP were 11.2%, 60.0%, 60.2% and 27.3%, respectively. The removal mechanism of ammonia nitrogen and nitrate nitrogen by water spinach was mainly dependent on microorganism, where as phosphorus removal by water spinach was mainly due to plants absorption.