Applying nutrient recovery from unused wastewater to overcome fertilizer shortage for global food security

The global fertilizer shortage, intensified by rising energy costs, geopolitical conflicts, and supply chain disruptions, threatens food security and agricultural productivity worldwide. This study explores the transformative role of circularity in the chemical sector, specifically through resource recovery from municipal and industrial wastewater, to mitigate the growing nutrient deficit in agriculture. Phosphorus (P), nitrogen (N), and potassium (K)-the core nutrients in synthetic fertilizers-are increasingly recoverable from waste streams using advanced technologies. The literature survey indicates that up to 90 % of P and 60 % of N in domestic wastewater can be recovered through technologies such as struvite crystallization, ion exchange, and membrane bioreactors. Pilot projects in Germany, the Netherlands, and China have demonstrated the viability of producing struvite-based fertilizers at a cost of 20-30 % lower than conventional fertilizers, with comparable or higher agronomic performance. Moreover, one mid-sized wastewater treatment plant (WWTP) can generate up to 150-300 tons of recovered phosphorus annually, enough to meet the needs of 2500 ha of cropland. By adopting circular approaches, countries can reduce dependency on imported fertilizers, lower GHG emissions by 35 %, and simultaneously improve wastewater effluent quality. Additionally, this circular model supports the Sustainable Development Goals (SDGs) 2 (Zero Hunger), SDG 6 (Clean Water and Sanitation), and SDG 12 (Responsible Consumption and Production). However, barriers remain, including regulatory gaps, limited market acceptance of recovered fertilizers, and technological scalability challenges. This study recommends establishing incentive-based regulatory frameworks, public-private partnerships, and investment in decentralized recovery systems. Overall, closing nutrient loops through wastewater-derived fertilizers presents a scientifically proven, economically viable, and environmentally sustainable solution to combat fertilizer shortages and enhance global food security due to escalating challenges.