The Study Of Constructed Wetland Technology To Water Purification On The Riparian Zone Of Water Supply Reservoir

Clean and safe water resource is an important support for healthy living and sustainable development of economy. Most of the centralized water supply sources in China are faced with different levels of sediment or nutrient pollution, which makes the situation of protecting the water sources grim. Constructed wetland technology, which has been widely used in the restoration and management of the water-source region, has the advantages of good comprehensive benefits, low construction cost, simple management and so on. Accordingly, focusing on the pollution treatment on the riparian zone of water supply reservoir which has seldom been paid attention to, the author makes a research on constructed wetland technology to wastewater advanced treatment on the riparian zone of water supply reservoir. The riparian zone of the estuary of Geli River in Biliuhe Reservoir is selected as the research subject. Through the analysis of the pollution situation in the region, the corresponding constructed wetland process and scheme are proposed, and evaluation of the comprehensive benefit of the wetland is made. The research contents and results are as follows:(1) Firstly, pollution investigation of the riparian zone of the estuary of Geli River is done, and then main pollution sources and characteristics of them are analyzed. The pollution sources are mainly non-point source pollution, including domestic pollution from rural life and agricultural non-point source pollution. They are domestic pollution from Guiyunhua, agricultural non-point source pollution in estuarine waters, domestic pollution fromYanglanzi and Tucehng. Pollution of this area has such characteristics as with a large number of emissions, high storage coefficient, complex sources of pollution, pollutant collection and treatment difficulties and so on. These characteristics should be regarded as an important part in the control of the reservoir water pollution.(2) The study of constructed wetland technology to water purification on the riparian zone are as follows. The biological and physical effects of constructed wetlands adapt the unstable features of the non-point source pollution and have a good purification effect on the non-point source pollutants. Taking the Geli River entrance waterfront as a typical case, this research studies on the constructed wetland technology to water purification on the riparian zone. Combined with the characteristics of pollution sources and the water quality requirements in this area, pollutant emission are classified to concentrated discharge of domestic pollution and mixed emission of light pollution. By comparing the treatment process, the realistic wetland treatment process is selected for wastewater purification. The measures mainly include adding the sewage treatment station to the deep purification wetland of two-stage vertical flow constructed wetland and surface flow constructed wetland as a pretreatment project to domestic sewage, which is concentrated discharge in the riparian zone of reservoir, using the methods of arranging the graded and stepped series surface flow wetland to the mixed emission of light pollution. Combined with the characteristics of pollution sources in Guiyunhua, Yanglanzi and Tucheng, its structure is improved for adaption and improving the efficiency of the wetland treatment, The constructed wetland technology to water purification on the riparian zone of water supply reservoir and the optimization of wetlands proposed by this paper can a reference for the design and construction of similar constructed wetland water purification project.(3) Combined with the characteristics of the constructed wetland on riparian zone of reservoir and the construction goal, this research studies on the evaluation indexs of the comprehensive benefits, which includes ecological benefit, economic benefit and social benefit. these indexes are climate regulation, hydrological regulation, purifying water, biological habitat and wetland products. Evaluation index system of the comprehensive benefits of the waterfront wetland is built and applied to comprehensively evaluate the benefits. And the results show that the comprehensive benefits of the project area increased by RMB 2.3911 million per year. Significant economic benefits and social benefits have emerged, and the benefit of ecological environment has been greatly improved compared with the original natural state in this area.