Energy, Environmental, and Economic Trade-offs for Wastewater Recycling in the Indian Water System: Regionalized Life Cycle Inventory Development and Analysis

Wastewater recycling represents a circular economy approach to water conservation, but it is not necessarily deemed sustainable. A comprehensive investigation of the energy, environmental, and economic trade-offs is essential before adoption. This study presents a life cycle and technoeconomic assessment of different recycling alternatives for a representative urban water system located in an Indian suburb. This study explored indirect, direct, nonpotable, and hybrid wastewater reuse alternatives at the city scale, incorporating construction and operation phase inputs in the system boundary. A regionalized life cycle inventory was developed from the actual water system using electricity bills, drawing sheets, and other onsite resources. Standardized modeling approaches were adopted for assessing the embodied energy, GHG emissions, and the levelized cost of the alternatives. Results showed that direct potable reuse can save over 50% of freshwater; however, its energy, emissions, and cost were 64, 25, and 166% higher, respectively, compared to the baseline. Centralized nonpotable reuse was the most favorable scenario with water savings of ∼40%, 9% lower GHG emissions, and 8.8% lower cost. Wastewater treatment for reuse and piping infrastructure are environmental and economic hotspots. The results and the database presented are valuable to be utilized as a tool for identifying alternatives to design sustainable water systems based on a quantitative approach.