Enhancing circular economy in Fes-Meknes region: substituting chemical fertilizers with olive mill wastewater for fertilizer value, economic benefits, and environmental footprint reduction

This article presents a comprehensive and multidisciplinary analysis of the circular economy in agriculture, focusing on replacing chemical fertilizers with olive mill wastewater (OMWW). The study involved evaluating the physicochemical characteristics of OMWW in the Fes-Meknes region, determining their production volume, and assessing their economic potential. The physicochemical characterization of OMWW was conducted using the Rodier protocol, and OMWW deposits were estimated based on a mass balance approach for each system. The fertilizer potential was then evaluated by combining the characterization results with the annual production quantity, and the economic value was calculated based on current market prices. The study’s results indicate that the characterization of OMWW is in line with spreading standards and that it is rich in nutrient elements, including approximately 835 tons of nitrogen, 46 tons of phosphorus, 5.7 kilotons of potassium, and 63 kilotons of organic matter. These findings highlight the significant economic opportunity of valorizing OMWW for the region, with potential gains estimated at around $560,000 for nitrogen, $68,966 for phosphorus, and $2.3 million for potassium. In conclusion, this study proposes a viable solution for sustainable agriculture in the region, thereby making a tangible contribution to agricultural development while preserving soil and water resources and mitigating the carbon footprint associated with their management.