Synergetic Benefits of Agricultural Sewage Reuse and Floating Photovoltaics in Mexican Wastewater System: A Municipal-Level WEF Nexus Study.

Financial stability is essential for the sustainable operation of wastewater treatment plants (WWTPs), as they require substantial resources but generate minimal revenue. In Mexico, a lack of funding resources and supporting policies has resulted in inefficient treatment and extensive surface water degradation. This work examines the positive impacts of treated sewage-operated irrigation ponds equipped with floating photovoltaics on the WWTP's economic viability in central Mexico. These ponds will provide water for irrigation expansion in rainfed cornlands, and the harvested solar energy will be exported to the national grid to independently generate income. The turnover will cover capital and operational expenditures of WWTPs, irrigation ponds, FPV, and energy for irrigation. The proposal's performance is evaluated through techno-economic and Water-Energy-Food Nexus assessments on municipal level. It is projected that by in-situ recycling 35% of generated sewage, local corn growers could benefit from an additional 45 320 hectares (223%) of irrigated cornland, over 5 46 000 tons (132%) of corn grain production, and 139% more sales revenue. The overall power capacity of FPV units could reach 834 MW, and 1796 GWh of clean energy could be harvested annually. This example demonstrates the value proposition of irrigation ponds and FPVs on the sustainability of existing WWTPs globally.