Fuzzy Borda combined model in small town's sewage treatment process alternative selection

Abstract

With the increasing pressure of sewage treatment in small towns, it is necessary to establish a set of systematic and objective evaluation systems to select the most suitable sewage treatment technology in small towns. In this paper, according to sewage characteristics, sewage disposal difficulties, treatment requirements and development of small towns in China, seven processes were selected as follows: A/O, oxidation ditch, CASS, SBR, biological contact oxidation, BAF and artificial wetland. The evaluation index system was set up through literature research and consulting experts. Comprehensive index method, analytic hierarchy process and weighted arithmetic average method were used to evaluate the priority of each process. The consistency was tested by Spearman rank correlation coefficient. Based on three single evaluation results, fuzzy Borda combination evaluation model was established to evaluate the priority of sewage treatment process. Finally, an example was introduced to prove the feasibility of the combination evaluation model.