Research On The Encironmental Impact Load Of The Urban Wastewater Treatment Plant By The Methord Of Life Cycle Assessment

As an environmental protection project, wastewater treatment plant plays an irreplaceable role in conserving water recourse and reducing the pollution. However, wastewater treatment plant produces lots of contaminants in its life cycle, which are bad for environment. This study analyzes the environmental impact load of an urban wastewater treatment plant by the method of life cycle assessment (LCA).Firstly, this study divided the life cycle of the wastewater treatment plant into three stages by the method of life cycle assessment, the process of the raw material production and transportation, the process of operation, the process of demolition. And this study make the annul handing capacity of wastewater the treatment plant as the function unit, that is FU=7.3X106t/a. According to the results of life cycle parts division, this study works out a data list of the wastewater treatment plant.Secondly, this study divides the environmental impact load of the wastewater treatment plant into ten categories:global warming potential (GWP), non-renewable resource consumption, renewable resource consumption, landfill space consumption, water quality impact (WQP), air quality impact (AQP), eutrophication potential, acidification potential (AP), photochemical smog impact (POCP), human health impact. Then, this study calculates the load of every kind of environmental impact by the models published by the environmental protection agency of United States. At the end, this study values the environmental impact load by the weight, which is drawn by the method of nine scale and analytic hierarchy process (AHP). The final environmental impact load of the wastewater treatment plant is5359.344t/FU. The largest part is global warning potential,2717.873t/FU,50.713%of the whole environmental impact load. The second largest part is non-renewable resource consumption,1326.440t/FU,24.750%of the whole load, renewable resources consumption,1056.lt/FU,19.705%; landfill space consumption,204.008/FU,3.807%; water quality impact36.854t/FU,0.688%; air quality impact6.072t/FU,0.113%; eutrophi cation potential,5.922t/FU,0.108%; acidification potential,5.615t/FU,0.105%; photochemical smog impact0.450t/FU,0.008%, human health impact,0.008t/FU,0.001%.From another aspect, operation process has the largest environmental impact load of the wastewater treatment plant,4421.067t/FU,82.493%of the total.At last, this study gives an interpretation of the life cycle assessment. And according to the characteristics of the environmental impact load, this study puts forward some measures to control and reduce the environmental impact load.