An exploration of comprehensive evaluation method of sewage treatment construction project in small and medium towns: theory and application

摘要

Based on the investigation of Chinese sewage treatment construction projects, it is of importance to develop a comprehensive evaluation method associated with socioeconomic and environmental consideration, especially in small and medium towns. A comprehensive evaluation method was established based on analytic hierarchy process method with the quantitative or semi-quantitative evaluation indexes from field of technical benefit, economic benefit, environmental benefit, and social benefit. The weights of technical benefit, economic benefit, environmental benefit, and social benefit were 0.4597, 0.3437, 0.1272, and 0.0694, respectively. The technical and economic benefits were relatively more important. A practical sewage treatment plant in Economic Development Zone of Huangzhou, China, was put forward to test and verify this improved method. Results indicated that the pretax financial internal rate of return (FIRR) (7.43%) and after-tax FIRR (4.53%) of the plant were all greater than benchmark yield of sewage treatment industry (5% pretax and 4% after tax). The pretax payback period (P t) was 15.34 years, while that of after-tax was 15.77 years. In addition, environmental benefit evaluation indicated that environmental cost-benefit ratio was 1.38 in the first phase and 1.67 in the second phase, which meant positive benefit for environment. Evaluation of technical benefit and social benefit also confirmed that the project meet demands of the industrial park and society. The final comprehensive benefit evaluation result was 7.0249, which indicated that the sewage treatment plant was in average level to maintain normal operation.