Developing a Water, Food, Energy, Economy, and Environment Nexus Index for Evaluating Centralized and Decentralized Wastewater Treatment Systems

ABSTRACT In addressing the complex challenges of sustainable development, the Water‐Energy‐Food (WEF) nexus underscores the critical role of wastewater management. This study evaluates centralized and decentralized wastewater treatment systems using the innovative Water‐Energy‐Food‐Economy‐Environment Nexus Index (WEFEENI). Centralized systems are traditionally favored in urban settings due to economies of scale, yet they encounter high costs and environmental impacts. In contrast, decentralized systems offer flexibility and lower operational costs, making them suitable for less populated regions. Our findings reveal that decentralized systems significantly reduce energy consumption by 72.88%, investment costs by 52.01%, and operating costs by 87.98%, while also lowering greenhouse gas emissions. Although centralized systems excel in food production and annual income, decentralized systems perform better in water and energy productivity, green space development, and aquifer recharge. The study highlights the importance of adopting a holistic approach, tailored to specific contexts and priorities, to achieve sustainable wastewater management.