Biomineralization-driven simultaneous carbon/phosphorus recovery and membrane fouling control in anaerobic membrane bioreactor for swine wastewater treatment.

The high phosphorus (P) containing in swine wastewater (SW) presents as both an environmental hazard and a potential source of high-value phosphorus resource. This study presents a biomineralization-driven Fe-P crystals (FePs) metabolism to facilitate simultaneous pollutant removal, energy recovery, and membrane fouling mitigation in SW treatment. The approach enhanced methane production from 0.20 ± 0.05 to 0.29 ± 0.02 L CH4/g COD while achieving 96.8 ± 1.7 % TP removal. Our result is explained by the proposed concept that included the facilitation of partial Fe3+ reduction to Fe2+ by Clostridiaceae. In addition, the concurrent upregulation of key phosphorus metabolism genes (ppk, phoA, and phnP) that enhanced extracellular phosphorus hydrolysis, leading to the release of PO43- was also reported. The released phosphate then participates in biomineralization along with Fe2+, forming high-value vivianite (Fe3(PO4)2·8H2O) during organic degradation. After PO43- is fixed, its free concentration decreases, resulting in the inhibition of PO43- uptake by microorganisms, thus having a positive impact on the expression of Ugp. Microorganisms turned to sn-glycerol 3-phosphate and other phosphorus compounds to meet their P needs. Concurrently, vivianite contributed to membrane fouling mitigation through hydrodynamic flushing and extracellular polymeric substances (EPS) degradation on the membrane surface. Archaea such as Peptostreptococcaceae and Anaerolineaceae were enriched on the membrane, which also promoted the degradation of membrane organic fouling. This innovative strategy advances the paradigm of wastewater treatment by transforming conventional pollutant removal processes into integrated resource recovery systems, offering both technical and economic advantages for sustainable SW management.