LCA Of Wastewater Treatment Processes In Liao River Basin Of Jilin Province And Process Preference Study

As an important high-quality commercial grain base in China,the Liao River Basin in Jilin Province has an important strategic position in national grain production and supply.The Liao River basin in Jilin Province is in the upstream section of Liao River system.Due to the influence of climate change,the precipitation in the area is low,the natural runoff is low,water resources are scarce,and the ecological base flow of the river is insufficient,which makes the river breakage problem more serious.Sewage treatment is an important measure for ecological environmental protection,that is,all kinds of sewage is treated by sewage treatment technology and then discharged after meeting the discharge standard to reduce the environmental pollution caused by high concentration sewage.The use of unsuitable sewage treatment process will lead to waste of resources,unsatisfactory sewage treatment effect and other phenomena,indirectly leading to resource and energy consumption and more serious environmental pollution.Therefore,on the basis of environmental impact assessment,comparing different wastewater treatment processes is the key to better play the efficacy of comprehensive pollutant purification in wastewater treatment plants.In this study,life cycle assessment（LCA）based on life cycle assessment theory（LCA）and Gabi 9.0 software was used to conduct life cycle assessment of environmental impacts generated by two wastewater treatment plants using A~2O process and CASS process in Liao River Basin,Jilin Province.The Re Ci Pe 2016 v1.1Midpoint（H）method was selected for the contribution analysis and Gabi software for the LCA.Seven environmental impact evaluation indicators were selected based on three aspects of resource depletion,ecological impact,and human activity impact,and finally relied on Yaahp software to establish a hierarchical structure model with four layers,10 indicators,and two options using the hierarchical analysis method（AHP）to combine three aspects of economic benefits,environmental impacts,and technical performance to comprehensively evaluate the A~2O process and CASS process,and preferably select the most suitable wastewater treatment process in the Liao River basin of Jilin Province was selected.The results show that（1）the environmental impact of the A~2O treatment process is significantly smaller than that of the CASS process,and the environmental impact contribution of each stage of the wastewater treatment process is shown as biological treatment stage>pretreatment stage>sludge treatment stage;（2）throughout the wastewater treatment stage of the A~2O process,there is a great impact on various environmental categories,of which the fossil depletion potential is the most affected environmental indicator（44.3%）;（3）In the pretreatment stage of wastewater treatment,the CASS process has the greatest impact on the environmental impact value of FDP,while in the biological treatment stage,the FDP contribution of the A~2O process is greater than the other stages,accounting for 71%of the total contribution value;（4）Based on the hierarchical analysis method,a hierarchical analysis model was constructed by integrating three aspects:economic benefits,environmental impacts,and technical performance,from which it was concluded that technical performance was the most important environmental impact indicator.The research results show that the total target results of A~2O process and CASS process are 0.5280 and 0.4720,and the larger the value,the higher the suitability,so A~2O process is the most suitable wastewater treatment process in Liao River Basin of Jilin Province.The purpose of this study using life cycle assessment research is to evaluate the environmental impacts caused by different wastewater treatment processes and to provide decision makers with a method that has less environmental impacts when selecting wastewater treatment processes.