Multiple Benefits of Deploying Wastewater Phosphorus Recovery Strategies in China: A Spatially Explicit Scenario Assessment.

Phosphorus (P) management faces dual pressures from finite mineral resources and waterborne pollution. Recovering P from wastewater offers a strategic pathway to alleviate both constraints simultaneously, yet systematic evaluations remain scarce, particularly with respect to recovery pathways, regional heterogeneity, and integrated co-benefits. Using city-level data covering more than 600 cities, we quantified wastewater P flows and recovery potential across China. In 2022, 0.049 Mt P was recovered (21.9%), concentrated in eastern and northeastern China. We identified land use, technology investment, and sewage-sludge treatment as key correlates of recovery, while agronomic and technology-specific efficiencies most influenced scenario outcomes. Under the sewage sludge ash recovery scenario, recovery could rise by 288% to 0.190 Mt P, offsetting up to 6.6% of annual cropland P fertilizer demand while generating approximately USD 356 million. Average waterborne P discharge would decline by 30% during implementation relative to the Current baseline, with the 2030 value reaching 0.146 Mt P. These findings provide a robust quantitative basis demonstrating that wastewater P recovery represents a cost-effective strategy capable of delivering a synergistic triple-win for food security, environmental protection, and economic returns.