GIS-based optimization for the locations of sewage treatment plants and sewage outfalls – A case study of Nansha District in Guangzhou City, China

Based on GIS technology, eco-suitability evaluation method integrating economic, social and ecological factors is employed to optimize the locations of the sewage treatment plants and outfalls in this paper. The ecological indices considering eco-sensitivity areas as key elements of the integrated evaluation system are allotted to the water subsystem, riparian zone subsystem, and land subsystem. A novel integrated eco-suitability evaluation index system encompassing ten criteria and fifteen indices is established to generate the distributed eco-suitability map of the concerned areas and determine the possible locations of sewage treatment plants and sewage outfalls according to the eco-suitability levels. With the case study of Nansha District in Guangzhou City, China, 212 km2 areas of land are found to be suitable for locating the sewage treatment plants, 87 km2 areas of water suitable for sewage release, and 6 km2 area of riparian zone unsuitable for sewage outfalls.