Research On Comprehensive Evaluation Index System And Method In Wastewater Treatment Plant

As an infrastructure work good for social development, ecological circulation, human health, wastewater treatment plant plays a active role in reducing water environment pollution and saving water resource utilization. However, it has not yet formed a set of comprehensive evaluation index system that is comprehensive, objective and systematic. The assessment of wastewater treatment plants always focused on measurement of effluent discharge and economic construction investment. Therefore, this article mainly studied the establishment of comprehensive evaluation index system of wastewater treatment plant and the discussion of some relevant assessment methods.Based on life cycle assessment and cleaner production, this article discussed about the wastewater treatment plant's effects in the wastewater treatment process. From five aspects of the resource and energy consumption, environmental impact, human health and ecological toxicity, economic and technical performance, selecting 22 indicators, it established a suitable set of comprehensive evaluation index system of domestic wastewater treatment plants. By using analytic hierarchy process (AHP), it determined the weights of the selected indexes. The introduction of three-scale method ensured the accuracy of the evaluation results, and the excel programming reduced the calculation greatly. Besides, it classified the quantitative indicators and qualitative indicators of the selected indicators, and according to the statistical data of 34 wastewater treatment plants in Heilongjiang it established the evaluation criteria for the further foundation of realizing the quantitative scores. Finally, it established the comprehensive evaluation model of wastewater treatment plants by using the calculation of rating scores in cleaner production, that was the sum of weight mutiplied by the corresponding scores.From the weight of each index, we can see that the greatest impact was global warming which is 0.203, followed by the water consumption, water eutrophication, the proportion were 0.149, 0.114. But the proportion of operation management, noise, environmental management indicators were smallest. In order to test the feasibility of the assessment model, this paper took two wastewater treatment plants as the object of research for the study. It calculated each plant's total environment impact load of wastewater treatment plant A and B, 8.35t/a and 4.65t/a, and evaluated the different environmental contribution among the pollutants. The contribution of solid waste was the highest, followed by resource and energy consumption. Meanwhile it computed each wastewater treatment plant's score by applying the evaluation model. Because both wastewater treatment plant A and B scored more than 80 points, so they were in good operating condition, consistent with the actual operation. In the light of calculation results, it analyzed the shortcomings in the operation process of two wastewater treatment plants, and put forward some corresponding improvement measures, such as the need to improve the research on sludge reduction to reduce the impact of solid waste, etc.The results showed that the evaluation model was scientific and practical for the policymakers to have the idea and methods of comprehensive evaluation in wastewater treatment plant.