Life Cycle Assessment of Technological Shifts in Municipal Wastewater Treatment Plants

Abstract

The challenges faced by municipal wastewater treatment plants (WWTPs) to improve effluent quality while reducing environmental impacts are increasing. This study employs a Life Cycle Assessment to evaluate the development of effluent water quality and overall environmental impacts through seven years of technological advancements at a WWTP using real world data. Scenarios include biogas optimization, transitioning to biological phosphorus removal, solar energy integration, optimized effluent control and hypothetical quaternary wastewater treatments (ozonation and sequential H₂O₂ treatment). Transitioning to biological phosphorus removal reduced chemical use by 26.2% and achieved the highest nutrient removal efficiency but increased energy consumption, slightly raising fossil depletion (FD). Solar energy reduced FD by 18.4% and contributed 7.75% of energy needs, albeit with seasonal limitations. Optimized effluent control achieved the highest level of nutrient removal, improving freshwater eutrophication by 41.4% but increased sludge production by 10.4%, leading to a 23.9% rise in metal depletion. Ozonation significantly increased environmental burdens, while sequential H₂O₂ treatment had less of an impact, offering future potential for wastewater reuse. The findings underscore the importance of balancing energy, chemical use and effluent quality with biogas optimization playing a key role in reducing flaring. This study highlights the trade-offs inherent in WWTP upgrades and provides actionable insights into optimizing environmental performance.