Study On Water Pollution Characteristics Of Baiyangdian Lake And Water Quality Improvement Technology Based On Plant Purification

Aimed at the actual needs of eco-environmental management and protection,this paper estimates the annual total amount of pollution discharged into Baiyangdian Lake and its contribution rate to water pollution by means of analyzing the types and sources of pollutants.Meanwhile,the water quality of Baiyangdian Lake was regularly monitored,which leads to the understanding of the characteristic of the water pollution;additionally,research on water quality improvement technologies based on plant purification had been carried out,the achievements of which are as follows:The total amount of pollution and its sources were determined.The annual total amount of COD discharged into the Lake is about 11585.7 tons along with mainly three sources,which are inflow rivers(35.7%),livestock waste(23.7%)and aquaculture(20.8%).The annual total amount of ammonia nitrogen discharged is around 534.5 tons,the sources of which includes livestock waste(33.0%),inflow river(27.5%)and industrial waste(15.0%).The annual amount of total phosphorus discharged is 'about 342.8 tons,which mostly come from livestock waste(47.4%),aquaculture(27.1%)and inflow rivers(21.9%).The characteristics of spatial and temporal distribution of water quality in Baiyangdian Lake were clarified.The water quality gradually improved from estuaries to the center of the lake,where the permanganate index,ammonia nitrogen and total phosphorus reached the Class ? of the surface water environmental quality standard.In general,the water quality in the northern area of the Lake was better than that in the central area.Furthermore,the water quality in spring was better than that in summer and autumn in the cross sections of Shaochedian,Wangjiazhai,Guangdianzhangzhuang and Zaolinzhuang in the northern area,while the water quality in summer was better than that in spring and autumn in the cross sections of Quantou and Caiputai in the central area.Apart from excessive COD,there was a problem of excess of total phosphorus in partial section of estuaries,wherein the annualtotal phosphorus attained Class V in Duancun and even inferior Class V in Nanliuzhuang.In addition,a plant disposition pattern with the aim of water purification was selected.Six aquatic plants including Iris,Canna,Alisma,Sagittaria,Lythrum and Typha minima were used to purify the polluted water in Nanliuzhuang.Results showed that the removal rate of ammonia nitrogen by each aquatic plant is over 90%.In terms of the removal of total nitrogen,Canna(50.75%)performs better than Lythrum(49.45%)and Typha minima(23.63%);As for total phosphorus removal efficiency,Lythrum(69.45%)has the similar performance as Canna(68.15%),which is much better than Typha minima(43.28%).By comparison,Alisma,Sagittaria and Iris shows inadaptability to the external environment.During the experiment,Alisma and Sagittaria were affected by insects and diseases while the roof of Iris rotted,indicating that these three plants are not suitable for water purification in Nanliuzhuang area.