The Research Of Pollution Prevention And Control Technologies On The Xiquan Lake Water Environment

ShenBei New District was approved by the State Council as the fourth new area in Shenyang city in 2007. In order to realize leap-forward development, ensure the safety of city water supply, remedy polluted water environment and solve severe water shortage problem of Shenyang city thoroughly. Therefor,It proposes Xiquan Lake as water supply source and ecological environment protection zone in Shenbei New Area of Shenyang city.Xiquan Lake is one of the most important natural wetland in Shenbei New Area, Shenyang city. It locates Huangjia Xibe in Shenbei New Area, Shenyang city. The Xiquan Lake wetland is the convergent point of three upstream rivers: Xinxixiao River, Wanquan River, Yangchang River. The north of wetland, there is Shifosi reservoir. The south of wetland connects with Wanquan River and Yangchang River embankment. Three rivers water quality is rather serious. They will be a threat to build storage water sources as supply resources of groundwater. At the same time, after Shifosi reservoir water impounding caused the rising of groundwater level and immersion problem surrounding area. Therefore, in order to ensure water quality and water quantity security of water sources, improve water resources of Xiquan Lake water environment. This paper main research contents are as follows:1. Analysis and assessment for water environment quality of Xiquan LakeAssessment method adopts water quality identification index for Shifosi reservoir water quality. The water quality of reservoir is inⅣ～Ⅴcategory in dry seasons, the water quality is inⅡ～Ⅲcategory in flood seasons. The water quality of reservoir is very poor, this is primarily due to the poor water quality for Liao River after Shifosi reservoir water impounding; Assessment method adopts fuzzy comprehensive evaluation for Xinxixiao River, Wanquan River, Yangchang River that the three rivers are the tributary of Liao River and Xiquan Lake wetland. The water quality of three rivers and wetland all belongⅤcategory in dry seasons, they are respectivelyⅠ,Ⅴ,Ⅲ,Ⅲcategory in flood seasons;Assessment method adopts aggregative index number for the ground water quality of Xiquan Lake. The evaluation result show that the water quality grade is 5 in dry seasons, the grade is 4 in flood seasons. The main reason is due to the hydrogeo-logical condition and stratigraphic information, causes high Fe and Mn content. Therefore, the water quality could reach national drinking water level standard as long as to treat lightly.2. The study of hydrogeology testBased on adsorption study during the growing and non-growing plants in wetland, the reaction rate are respectively are 5.64(1/d) and 4.05(1/d). The reason are probably related to the growing of root strengthen the sorption of soil to contamination. When the adsorption achieved when saturated, soil and plants consider as N buffer to a certain extent.The prior pumping test, infiltration test and dispersion test ascertain Kd ,K,αL.3. The mathematical model of Xiquan Lake surface water environmentThe national standard function of Xiquan Lake wetland isⅢcategory. Simulated result by QUAL 2K software show that the pollutant density at Xinxixiao River Bridge, Wanquan River Bridge, Yangchang River Bridge. The national standard function of Shifosi reservoir isⅢcategory. Simulate and predict spatial variation of TN index by Aquasea software in Shifosi reservoir water quality,it can be used for the mathematical model of groundwater in Xiquan Lake.4. The coupled mathematical model of surface and groundwater environment in Xiquan LakeSimulated result by QUAL 2K software show that the water level and water quality after establishing water source. Water quality simulated results show Shifosi reservoir water quality affect barely on ground water quality.Water level simulated results show that the amount of water could reach water demand after the storage water sources established. At the same time, it can solve immersion problem surrounding area due to reservoir water impounding.5. Propose optimized pollution prevention technologyConsidering wetland national standard function isⅢcategory. Propose three water pollution prevention and control technologies.The first one is constructed wetland,the second one is wastewater treatment plant,the third is the connection of front damming and constructed wetland. Water quality result show three project are feasible.Through comparative analyses among them, ensure technology to combine pretank and wetland is the optimization measure.