Processes and drivers of biological and chemical Phosphorus removal in wastewater treatment plants

Phosphorus (P) is one of the most important elements exists in wastewater in soluble forms. Several methods have been using for P recovery in wastewater treatment plants, but this study tried to investigate on the most important drivers and the processes of biological phosphorus removal (EBPR) and chemical phosphorus removal that are the major technics of P recovery globally. It has been considered that EBPR is a high recovery method (normally greater than 90%) which could be implemented in different regimes with the integration feasibility of different methods, while chemical precipitation is a flexible technique that could be dosed in various section of a treatment unit. The performance and drivers of three metal-based salts such as Iron (Fe), Aluminum (Al), and Calcium (Ca) also investigated during chemical precipitation. The crystallization process is also investigated as a subcategory model of chemical P removal method. It has been considered that the alkaline pH of 9-9.5, mixing intensity, and the addition of isomorphic seed materials are the most important factors in the crystallization process