| Sewage treatment plant is an important part of the basic construction of municipal engineering in modern cities and an important project to solve urban water pollution problems.Sewage treatment itself is an environmental protection project,but the operation period of the sewage treatment plant will directly or indirectly generate a large amount of environmental pollutants.Therefore,it is necessary to analyze the environmental impact of the sewage treatment plant during the operation period.This paper analyzes the pollution sources,pollutant types and accounting sources of a proposed urban sewage treatment plant in Heilongjiang Province.Combining the traditional environmental impact analysis method and the LCA analysis method comprehensively analyzes and explores the environmental impact of the sewage treatment plant handling 1×104m3 sewage per dayduring the operation period.Using emission coefficient method and analogy calculates the quanteties of the pollutants from the treatment plant handling 1×104m3 sewage per day during the operation period of the proposed project:NH3?H2S?COD?SS?TN?TP?grid slag?grit chamber sand?secondary sedimentation tank sludge?water content:97.78%??mud cake?water content:78%?to prepare for subsequent environmental impact analysis.Based on the calculated emission intensity of NH3 and H2S,the SCREEN3 model is used to predict the concentration of NH3 and H2S produced by the sewage treatment plant during the operation period when handling 1×104m3 sewage per day,which take up50.90%and 10.90%of the“Industrial Hygienic Design Standard”?TJ36-79?,in addition,the discharge concentration of the factory boundary NH3 and H2S reaches the requirements of the"Emission Standards for Pollutants in Urban Sewage Treatment Plants".The research results show that the NH3 and H2S generated during the normal operation of the sewage treatment plant have little impact on the surrounding atmospheric environment,but in order to protect the health of the surrounding residents,a sanitary protection distance of 100m is also required.Based on the calculated emission intensity of COD and NH3-N,the two-dimensional steady-state model is used to predict that handling 1×104m3 sewage per day will reduce the COD emissions by 2544 kg and NH3-N emissions by 519.7 kg,and moreover,the concentration of COD and NH3-N within 1-20 km from the sewage outlet after the discharge of the sewage reached the standard is reduced by more than 80%compared with the concentration of the untreated discharge of sewage..It can be seen that after the sewage treatment plant is put into use,it will contribute to the improvement of the overall water quality of the Songhua River,however,since the amount of sewage is much smaller than that of the Songhua River,the overall effect is not obvious.After using the traditional method to analyze the environmental impact of the sewage treatment plant on the surrounding environment,the influence of electricity and chemical agents is also taken into account,based on the LCA thoery,then,the GaBi8.0software is used to predict the sewage treatment plant's operation period to treat 1×104m3 of sewage to the surrounding area,regional,and even global environmental impact,theresultsshowthat:MAETP>HTP>GWP>ADPF>AP>POCP>TETP>FAETP>ADPE>ODP,the total environmental impact potential is 4.21×10-8;Pretreatment>Secondary Treatment>Advanced Treatment>Sludge Treatment;In addition,when the transportation distance of the chemicals used in the sewage treatment plant is short enough,the sewage treatment plant can alleviate the eutrophication of the water,both in a small scope and in a wide range.This paper makes a useful exploration of the surrounding,regional and even global environmental impacts of a proposed wastewater treatment plant in Heilongjiang Province,provides decision support for managers to facilitate regional environmental sustainability. |
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