New strategies to achieve sustainable inorganic phosphorus (Pi) removal and recovery from water and wastewater are needed to overcome the limitations of conventional wastewater treatment technologies that can achieve Pi effluent concentrations of 1-2 mg/L. Approaches that could achieve lower Pi concentrations while also facilitating recovery to support a circular Pi economy are essential. Our research utilized an innovative biomimicry-based selective Pi adsorbent featuring high-affinity phosphate-binding proteins (PBP) as a potential sustainable treatment option. Here, continuous flow, packed bed column tests were used to investigate Pi adsorption using PBP immobilized on resin (PBP-NHS) targeting Pi removal from synthetic solutions and real wastewater samples. The selectivity of the PBP-NHS resin was evaluated using synthetic Pi-only and synthetic multi-ion solutions. The performance of the packed bed column of PBP-NHS resin was also evaluated using tertiary wastewater effluent (South Shore Water Reclamation Facility (Oak Creek, WI)). For tertiary wastewater, single-column experiments, a bed volume of 0.5 mL, flow rate of 0.3 mL/min, and influent Pi concentration of 0.75 mg/L was used. Furthermore, multi-cycle column experiments were conducted to assess PBP-NHS reusability (three adsorption-desorption cycles, controlled by pH adjustment). High Pi-selectivity of PBP-NHS resin was observed as there was no significant difference between the breakthrough curves of Pi-only solution and multi-ion solution (p = 0.81), with each having a breakthrough time of 20 min with 4 mL treated bed volume. Hence, the Pi adsorption capacity of the PBP-NHS resin was unaffected by competing anions. Using tertiary wastewater effluent, the PBP-NHS resin achieved 96% of its maximum theoretical capacity and there was no significant decline in the column’s performance over 3 consecutive cycles, substantiating the PBP-NHS resin’s reusability. The use of PBP-NHS resin in continuous flow treatment systems can improve P management strategies by achieving low initial Pi concentrations (in surface waters or wastewaters) and facilitating recovery of a pure Pi product.

Biosorption of phosphorus using immobilized phosphate-binding proteins in a continuous packed bed column

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.