Phosphorus Recovery Technology Modeling and Feasibility Evaluation for Municipal Wastewater Treatment Plants

Abstract

A computer model was used to evaluate the economic viability of implementing phosphorus recovery processes in municipal wastewater treatment applications. The model examines investment costs, sludge volumes, sludge disposal costs, chemical costs, and the value of recovered phosphates. The model specifically focused on: 1) representative phosphorus recovery technologies integrated with representative treatment scenarios for enhanced biological nutrient removal (EBNR) with a sidestream Crystalactor® application and for conventional biological treatment followed by mainstream (tertiary) Crystalactor application; 2) the value of recovered phosphorus, assuming recovery as calcium phosphate, with a similar value to that of phosphate ore (handling and transport costs are ignored); and 3) the impacts of phosphorus recovery on major operating costs. The model results show that phosphorus recovery is most cost-effective for high phosphorus and low biochemical oxygen demand (BOD) concentration wastewaters where sludge disposal costs are high. Phosphorus recovery can reduce sludge volumes produced by up to 30 percent (compared to EBNR) and up to 49 percent (compared to chemical phosphorus precipitation). Read-off graphs are also provided for specific conditions to assist facilities in conducting a preliminary assessment of the economics of phosphorus recovery for their facility.