Suitability Evaluation Of Locations Of Sewage Outfalls And Case Study

In recent years, with the growth of the population and the development of economic in China’s coastal areas, some problems to damage coastal environment begin to appear. Such as:the number of sewage outfalls is gradually increasing, the position isn’t unreasonable and the discharge of sewage is out of control. Thus, it is the key to address the issue of suitable locations for the sewage outfalls for achieving the goal of marine functional zones and it has profound theoretical and practical significance.Through the research on the hydrological, marine ecology and resource distribution characteristics of China’s typical waters, the paper has analyzed and summarized environmental constraint factors agreed by the different functional areas of marine environment. According to the marine environmental function zoning and the relevant provisions of national marine environment protection law, the principle of locations and scheme selections of sewage outfalls has put forward from a variety of angles. Secondly, on the basis of extensive consultation and investigation, the factors which effect the outfalls’locations has analysized. As a guide, location suitability evaluation index system of sewage outfalls has established from water subsystem and land subsystem. The evaluation index system covers 1system factor,2 criteria factors,8 two-level criteria factors and 11 specific indicators. According to the analysis of the factors effecting the location of the sewage treatment plants, location suitability evaluation index system of the sewage treatment plants has been constructed. The analytic hierarchy process (AHP) and grey relational model has been used in the selection of sewage outfalls. Finally, the technical guidelines had been complied to optimize the locations of sewage outfalls for providing a better technical and decision support.In addition, the area of Shishi in Fujian Province has been used for an example to optimize the locations of the sewage outfalls in this paper. Firstly, according to the local marine functional zoning and related laws and regulations, a preliminary choice has been conduct. Secondly, the multi-objective decision model is constructed to select the most suitable location of sewage outfalls.