Evolution of P Discharge Regulations in China: Necessity Analysis and Advances in Chemical P Removal Technologies for Wastewater Treatment

As eutrophication worsens, countries including China, the US, France, Sweden, and South Korea have tightened phosphorus (P) discharge limits for wastewater treatment plants (WWTPs). This paper first reviews China’s evolving P regulations, then classifies P removal technologies into physical, chemical, biological, and combined methods. Analysis of current WWTPs in China shows that biological P removal alone is insufficient, making chemical P removal (CPR) a necessary supplement or primary approach. Thus, the review focuses on CPR technologies: chemical precipitation, ion exchange, adsorption, electrocoagulation, magnetic methods, hybrid biological-chemical methods, and P recovery technologies. For each, the principles, materials, application conditions, advantages, and disadvantages are discussed. This review aims to guide the selection, application, and future research of CPR processes.