Phosphate as a resource: Current technologies and future directions for sustainable water quality management

Phosphorus, or its ionic form phosphate, is an essential nutrient that plays a critical role in sustaining life and agricultural productivity. However, its excessive discharge into aquatic environments has become a driving factor for eutrophication and water quality degradation. Understanding the phosphorus cycle and implementing proper management strategies are vital to balance its dual role as both a resource and a pollutant. This review highlights the environmental impacts of uncontrolled phosphorus discharge and emphasizes the importance of integrated water quality protection and phosphorus management. Conventional and emerging end-stage treatments, including chemical, biological, and physical methods, are discussed with the aim of closing the phosphorus loop. The recorded methods provide high phosphate extraction efficiencies, ranging from 12.16 to 99% for chemical, 20-98.1% for biological, and 19.7-100% for physical approaches, respectively. The advantages, limitations, and sustainability implications of these methods are also evaluated to identify opportunities for improvement. Finally, key challenges and future research directions are outlined, focusing on the need for cost-effective, energy-efficient, and environmentally sustainable solutions that enable phosphorus recovery from wastewater. Collectively, this review offers insights into the evolution of phosphorus management strategies and their role in achieving a circular nutrient economy and long-term protection of water quality.