Research Of Environmental Impacts Assessment Of Wastewater Treatment System Based On LCA

Wastewater treatment processes are among the top energy consumers and polluters and cause acidification and greenhouse effect. Environmental impact assessment (EIA) is an effective way to analyze, evaluate and forecast the environmental burden caused by the processes. Through the implementation of EIA, wastewater treatment processes can achieve the goal of saving energy, lowering consumption, reducing pollution and increasing efficiency. However, domestic EIA methods have its own limitations and can be easily influenced by subjective factors. In order to improve the accuracy of EIA results, life cycle assessment (LCA) is used for evaluating the impact of different wastewater treatment processes in this paper. It will help determining key pollution, achieving energy conservation and emission reduction by providing reference technically. The main contents of this paper include:(1) Using LCA, this article have built assessment model of the wastewater treatment system. The main process include determining system boundary, tracing El of input and making LCA inventories. The whole system can be divided into three parts to evaluate environmental impacts, which are wastewater treatment, transportation and sludge treatment.(2) The CML-Nov.2010 evaluating model was chosen for the characterization and normalization the environmental impacts of wastewater treatment system. Four notable environmental impact categories were considered in this study, which are Acidification Potential(AP), Eutrophication Potential(EP), Global Warming Potential(GWP) and Human Toxicity Potential(HTP). Results showed that the greatest contribution factors in the wastewater treatment processes were power and chemical consumption in wastewater treatment stage and pollutants from landfilling and flue gas emission in sludge treatment stage.(3) The comparison of two different processes of sludge treatment shows that using the damp-dry sludge and garbage mixed co-incineration process will cause the AP increased 23.82 times, the EP increased 6.86 times, the GWP decreased 0.79 times, the HTP increased 10.3 times and the electrical recovery increased 3.7 times.This paper combined LCA method and environmental assessment in wastewater treatment system, which can improved the evaluation of wastewater treatment process. This research can be used as technical guidance in energy conservation and emission reduction.