Phosphorus Recovery From Wastewater Through Anaerobic Digestion Under Sub-Supersaturation Conditions

Unlike conventional phosphorus (P) recovery methods that rely on high P concentrations and/or chemical additives, this study presents a cost-effective approach for inducing the precipitation of phosphate salts by utilizing carefully selected feedstocks and optimal operating conditions. To test the feasibility of this approach, three 1.0-L upflow anaerobic sludge blanket (UASB) reactors were operated, fed with three types of synthetic feeds, consisting of glucose + sodium acetate (NaAc), glucose + bovine serum albumin (BSA), and glucose + urea as the organic matter sources. All the organic compounds, including NaAc, BSA, and urea, which underwent hydrolysis to release hydroxyl ions, successfully created a favorable environment for the precipitation of P products like struvite and calcium phosphate under sub-supersaturation conditions. This study offers new perspectives on recovering P from waste streams with relatively low P concentrations.