Life cycle assessment of wastewater reuse alternatives in urban water system

Abstract

Increasing water stress necessitates adopting wastewater reuse for sustainable living in urban environment. Trade-offs exist between different wastewater reuse applications and their environmental impacts. The impacts associated with developing urban water systems (UWSs) are not known, and city scale wastewater reuse in general is not well understood. This study investigates indirect, direct, non-potable and hybrid wastewater reuse scenarios in a real UWS to suggest environmentally sustainable reuse strategy using life cycle approach. The study develops a comprehensive life cycle inventory of actual water and wastewater utilities. Results show that all environmental impacts except eutrophication increases for direct potable and hybrid reuse. The centralized non-potable reuse (NPR) had lowest impact scores related with ecotoxicities while impacts including global warming were equivalent to the baseline. The study recommends adopting centralized NPR in developing UWSs while highlighting the treatment processes and impacts for reuse scenarios favorable in high to extreme water stressed regions.