Environmental performance of an A2/O process for low-, medium-, and high-strength municipal wastewaters treatment by combining activated sludge modeling (ASM) and life cycle assessment.

This study aims to evaluate the environmental performance of a hypothetical wastewater treatment plant (WWTP) with activated sludge modeling and life cycle assessment (LCA). In order to simulate the treatment performance of an A2O (anaerobic-anoxic-aerobic) process for low-, medium-, and high-strength municipal wastewaters, activated sludge model no.3 (ASM3) was employed. Simulation results were then used for performing LCA of wastewater treatment plant to assess the environmental impacts associated with wastewater treatment system. Additionally, net environmental benefit (NEB) approach that is useful for wastewater systems was also used to determine the eutrophication potential reduction of the hypothetical WWTP. The LCA results show that global warming, photochemical oxidation, and eutrophication potential impact categories were affected by characteristics of wastewater treated. The highest values of these impact categories (7.87E-01 kg CO2-eq., 1.73E-04 kg C2H4-eq., and 1.28E-02 kg PO4-eq./m3.treated wastewater; respectively) were determined for high-strength wastewater. Considering eutrophication potential reduction, the highest NEB value was found 0.042 kg PO4-eq/m3.wastewater for high-strength wastewater, followed by medium-strength (0.027 kg PO4-eq/m3.wastewater) and low-strength (0.013 kg PO4-eq/m3.wastewater) wastewater. The results of the study is crucial to indicate that combining LCA with other decision support tools ensures achieving predictive and reliable results for proving the performance of WWTPs.