Life Cycle Assessment of Municipal Sewage Treatment Process: A Case Study from Harbin, China

There is an increasing focus on the secondary pollution of a municipal sewage treatment plant. To illuminate the environmental load of a sewage treatment process, a life cycle assessment (LCA) of a case project in Harbin was proposed by combining the process-based life cycle inventory (LCI) and the input-output based LCI in one framework. For classification of the effect factors and characterization, the calculation methods and models studied by Environmental Protection Agency (EPA) were applied and the improved analytic hierarchy process (AHP) was used to determine the indicator weights. Characterization results show that land filling space contributes to environmental load largely. Results of weighting assessment display the five bigger environmental impact categories. Results of LCA are intended to help inform and guide decisions about sewage treatment for existing wastewater treatment plants and those that are still in the planning phase in cities.