Selective phosphorus removal from wastewater by acid-modified vermiculite in membrane bioreactors

Wastewater phosphorus removal technologies have faced significant challenges, with paradigm-shifting from end-of-pipe removal to high-efficiency recovery. Membrane bioreactors (MBRs) have proven effective in removing chemical oxygen demand (COD) and total ammonium nitrogen (NH₄⁺-N) from wastewater yet demonstrate suboptimal performance in total phosphorus (TP) removal. This study successfully enhanced TP removal efficiency in MBR by employing acid-modified vermiculite. The results demonstrated that acid-modified vermiculite selectively enhanced TP removal, with the efficiency in the MBR increasing from 35 % to 74 % following the addition of both the carrier and acid-modified vermiculite. Microbial analysis revealed that incorporating acid-modified vermiculite altered microbial community structure, increasing the abundance of phosphorus-accumulating organisms and consequently strengthening TP removal. The operational cost of acid-modified vermiculite application was approximately ¥1156 per ton, demonstrating notable economic competitiveness in wastewater phosphorus removal processes. This research proposes a cost-effective acid-modified vermiculite approach that provides a feasible strategy for addressing phosphorus recovery and eutrophication challenges. © 2025 The Institution of Chemical Engineers.