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

## TL;DR

This study explores how reusing treated sewage for irrigation and adding floating solar panels can improve wastewater treatment plant finances and sustainability in Mexico.

## Contribution

The novelty lies in combining sewage reuse and floating solar to enhance wastewater treatment plant viability through the WEF nexus framework.

## Key findings

- Recycling 35% of sewage could expand irrigated cornland by 223% and increase corn production by 132%.
- Floating photovoltaics could generate 834 MW of power and 1796 GWh annually.
- The model could secure financial sustainability for wastewater treatment in the Atoyac River Basin.

## Abstract

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.

This study proposes integrating treated sewage irrigation ponds with floating photovoltaics to enhance wastewater treatment plants’ financial viability in the Atoyac River Basin, central Mexico. The model demonstrates potential to strengthen the water‐energy‐food nexus by recycling one‐third of sewage, increasing irrigation acreage on cornlands, boosting yields, generating clean energy, and securing the financial sustainability of the wastewater sector.