Environmental implications of increasingly stringent sewage discharge standards in municipal wastewater treatment plants: case study of a cool area of China

For the protection of the aquatic environment and public health, China has implemented increasingly stringent sewage discharge standards for municipal wastewater treatment plants (WWTPs), but faces critical challenges in terms of additional environmental burdens. In this work, a life cycle assessment (LCA) approach was used to determine the adverse environmental consequences of increasingly stringent discharge standards in a domestic WWTP, and to identify the main contributors and propose alternatives that minimize negative environmental impacts. The LCA-derived findings indicate that tightening discharge levels will indeed reduce local eutrophication but without net environmental improvement satisfied. If the treated water is not required for further reuse, it appears more environmentally promising to establish WWTPs in regions that implementing moderate-level treatment than to upgrade existing WWTPs to much higher standards, except in conservation zones, areas of high population density, and in watersheds with less resilience to pollution. Overall, environmental improvement can be satisfied by introducing consistent “cradle-to-cradle/grave” legislation for WWTPs. It was implicated that decision makers should therefore emphasize energy conservation and wastewater-derived resource recovery approaches to the operation of WWTPs.