Wastewater treatment technology selection under various influent conditions and effluent standards based on life cycle assessment

Abstract

Influent concentration and effluent standards have strong impacts on technology selection by wastewater treatment plants (WWTPs) and on resource recovery processes. In this paper, resource recovery simulation scenarios incorporated with conventional WWTP models were designed in an imitation of typical existing facilities. We integrated economic analysis and a life cycle assessment to evaluate the impacts of treatment technologies selected for different influent conditions and effluent standards. The results revealed that high concentration influents required the most complicated treatment processes to meet a strict effluent standard. The pattern of total impacts was strongly dependent on the influent conditions. High concentration influent was found to correlate with low energy consumption, low costs, a high nutrient recovery potential but also a high global warming potential when removing 1 kg of pollutants. The incorporation of resource recovery improved the overall performance of WWTPs; however, low concentration influents were not suitable for resource recovery due to their limited benefits. The strict effluent standard limited the resource recovery potential from wastewater, and a loose effluent standard may improve the resource recovery performance, especially for high concentration influents.