Abstract
Pharmaceutical residues in municipal wastewater present severe environmental threats due to their persistence and bioaccumulation potential in aquatic ecosystems. Conventional membrane bioreactors (MBRs) frequently demonstrate erratic degradation efficiencies for recalcitrant micropollutants and suffer from severe membrane fouling. In this investigation, a novel engineered biochar-supported titanium dioxide (BC-TiO2) nanocomposite was synthesized via a facile sol-gel pyrolysis route utilizing agricultural waste biomass and integrated into a submerged membrane bioreactor (P-MBR) to remediate three recalcitrant pharmaceuticals: sulfamethoxazole (SMX), carbamazepine (CBZ), and diclofenac (DCF). The synergistic coupling of biochar adsorption, visible-light-assisted photocatalysis, and biological oxidation achieved removal efficiencies of 98.4%, 91.2%, and 95.7% for SMX, CBZ, and DCF, respectively, under an operating hydraulic retention time of 8 h. Compared to a control MBR, the BC-TiO2 amended system exhibited a 62% reduction in trans-membrane pressure (TMP) escalation rate over an extended 60-day operational cycle. This fouling mitigation was primarily attributed to the catalytic breakdown of extracellular polymeric substances (EPS) and soluble microbial products (SMP) by reactive oxygen species generated at the composite interface. These findings validate the deployment of biomass-derived carbon nanocomposites as a circular, energy-efficient paradigm for enhancing micropollutant clearance while simultaneously prolonging membrane operational lifespans in advanced water reclamation facilities.
