Multi-criteria evaluation method for site selection of industrial wastewater discharge in coastal regions

Abstract The scientific and appropriate tools and methods to evaluate location of coastal plant effluent discharge as a guideline for decision makers is indeed an urgent need to address the increasing threats of pollutant to coastal waters in China. With an industrial wastewater plant located near the Luoyuan Bay coastal area in Fujian of China as a case, the present study investigated the suitability of the whole sea area of Luoyuan Bay for the establishment of sewage outfall using the proposed index system and Multi-Criteria Decision-Making (MCDM) tool. Based on literature review, expert consultation and Analytical Hierarchy Process (AHP), an index system with two categories, 5 sub-categories and 9 indicators including index grading and weighting were constructed. With Weighted Suitability Analysis (WSA) and Grey Relation Analysis (GRA) employed here as two optional methods to evaluate the most suitable alternative, a complete and systemic site selection technology was put forward to support the marine environment management. The results showed that, of the 6 optional sites that in consist with law, local regulations and functional zoning, ranking of alternatives by WSA and GRA both indicated that the site of S5 obtained the highest priority. For the other 5 sites, there was a difference between the ranking results calculated by two methods. We then discussed the difference between WSA and GRA and proposed their applicable conditions from perspective of decision makers.