Environmental profile of typical anaerobic/anoxic/oxic wastewater treatment systems meeting increasingly stringent treatment standards from a life cycle perspective.

Stringent new legislation for wastewater treatment plants (WWTPs) is currently motivating innovation and optimization of wastewater treatment technologies. Evaluating the environmental performance of a wastewater treatment system is a necessary precursor before proposing implementation of WWTPs designed to address the global requirements for reduced resource use, energy consumption and environmental emissions. However, developing overly-sophisticated treatment methods may lead to negative environmental effects. This study was conducted to employ a process modeling approach from a life cycle perspective to construct and evaluate six anaerobic/anoxic/oxic wastewater treatment systems that include a water line, sludge line and bioenergy recovery system and was designed to meet different treatment standards in China. The results revealed that improved treatments optimized for local receiving watercourses can be realized at the cost of higher resource consumption and greenhouse gas emissions. Optimal Scenarios were also identified from different positive perspectives.