Purification Efficiency of Three Species of Submerged Hydrophytes on Eutrophic Water in Summer and Autumn

An indoor static test was conducted to investigate the effect of nitrogen and phosphorus removed by three species of submerged hydrophytes in different seasons.The results revealed that: 1) The total nitrogen removal efficiency of submerged hydrophytes in summer was better than in autumn.Potamogeton crispus showed the best effect for nitrogen removal.2) The total phosphorus removal efficiency of submerged hydrophytes in summer was better than in autumn,Hydrilla vertillata showed the best effect for total phosphorus removal.3) The concentration of DO would increase if the submerged hydrophytes grew well,but the death and decomposing of plant would cause it reduced quickly in water.4) The death and decomposing of plant could significantly affect the total phosphorus concentration in water,but indistinctively affect total nitrogen concentration.5) There was significant correlation between the total phosphorus removal rate and water temperature.