Life Cycle Assessment And Comparison Of A/A/O And MBR Wastewater Treatment Technology

Wastewater treatment is a project to reduce the environmental pollution, the amount of pollutants can be reduced to environmental emission standards with treatment technology. The treated water have lower impact on the environment when compared with no treatment water. However, the wastewater treatment process itself also has impact on environment, and the characteristics of different sewage treatment processes and its direct impact on the environment are different. The traditional methodology which is often used to evaluate and select the wastewater treatment process called Technology- Economic comparison methods, but these methods did not fully consider the environmental impacts of different options.Life Cycle Assessment (LCA) is a new tool of environmental management, it evaluate a product, process or production of the environmental load with analyzing inputs and outputs the life cycle materials and energy quantitatively.The method are widely used in the field of industry, business and government administration.This study accesses and analyzes large amounts of papers at home and abroad, bases on principles and technical framework requirements of life cycle assessment in order to evaluate the environmental performance of Bei Xiao He wastewater treatment plant (A/A/O and MBR technology) in Beijing as a case and collects and calculates the data of the inputs and outputs of the wastewater treatment processes to list the life cycle inventory which includes the data of the energy, dosing of drugs and the process of sludge treatment and disposal.The Centre of Environmental Science (CML) of Leiden University methodology and eco-invent database were used to quantify the potential environmental impact associated with the whole system and its different stages under study, in particular a total of ten CML2000 baseline factors were chosen for characterization and normalization stages. The environment performance of the various processing units were evaluated, the greatest impact unit processes of the two wastewater treatment processes were identified and the main contributor to the process category of the two wastewater treatment processes were analyzed. The CML methodology of life cycle assessment were used to evaluate the wastewater treatment process, which provides a reference for the selection of the wastewater treatment process.The paper presents the results that in WWTP the biological and sludge treatment stages turn out to be the main contributors in the environmental load, and the WWTP has a significantly influence on eutrophication, aquatic ecotoxicity, global warming, acidification and depletion of fossil fuels .The contribution of MBR is less than A/A/O in eutrophication and global warming. Regarding the former, the quality of the discharged water with MBR technology is better; as for the latter, the quantity of the sludge with MBR technology is only one fifth of A/A/O. In other environmental impact indicators, MBR has a higher influence, due to its higher consumption of electricity and chemicals. Besides, the recommendations here are to use energy efficiently, use biogas to produce electricity, and use reclaimed water for non-potable uses rationally in order to reduce the environmental impact, which provide the basis to build more environmentally friendly, economic and sustainable development of the sewage treatment plant for the wastewater treatment plant to build, upgrade and transform.