A Faraday-FAO56 approach for optimizing circular reuse of urban wastewater and scrap metal in crop irrigation by electrocoagulation

Wastewater treatment by electrocoagulation (EC) using waste-derived electrodes is an emerging and promising solution for closing resource loops at urban-irrigated intersections. However, there is a knowledge gap in integrating crop water dynamics into this application. This article presents a framework to integrate agrometeorological analysis (FAO56 model) and waste information into energy and electrochemical models (Faraday’s laws of dissolution). The model was parameterized for a study site comprising a large institution surrounded by irrigated trees. On-site experiments showed that electrochemical dosages of aluminum (Al) and iron (Fe) scrap, as low as 0.2–0.6 g/m ³ , achieved significant removals (75–94%) of COD, BOD, TSS, and turbidity, and met irrigation standards. Onsite metal waste generation (593 kg/month) could accommodate ~ 98,000 m ² of surrounding irrigated lands. Crop production capacities of scrap metals (food per scrap) were estimated to reach 23.3 kg/kg, specifically for Al scrap. Energy demand could be maintained steady at 0.58 kWh/m³ by integrating crop water dynamics, allowing flexible renewable energy integration. Validation of model components revealed that estimating crop water demand comprised a larger uncertainty than modeling scrap electrode consumption. The reuse framework shows promising potential as a WEFE nexus application but raises some socioeconomic concerns such as impacts on scrap scavengers’ livelihoods. Pilot-scale experiments and wider assessments are strongly encouraged to gain improved insights.