Turbulent up-flow hydrodynamic optimization enables high-rate anaerobic membrane bioreactor for refractory PTA wastewater treatment

The treatment of purified terephthalic acid (PTA) wastewater by anaerobic membrane bioreactors (AnMBRs) is challenged by aromatic pollutant toxicity and membrane fouling. To address those, a novel Turbulent Up-Flow Compartmentalized AnMBR (TUC-AnMBR) was developed by creating a controlled turbulent up-flow regime generating strong hydrodynamic shear force to mitigate membrane fouling and enhance process efficiency. During long-term operation, the reactor achieved a high methane yield of 0.346 L·g-COD⁻¹, with total COD removal of >98.2% and aromatic compound degradation of >99.9% even at an ultra-short hydraulic retention time of 4 h. The imposed shear stress promoted the secretion of protein-rich EPS (extracellular polymeric substances) and facilitated cake-layer formation, thereby accelerating the re-granulation of small particles and the rapid development of robust granular sludge. This sludge environment enriched key syntrophic consortia, including Syntrophorhabdus (12.75%) and Methanobacterium (14.03%), enhancing direct interspecies electron transfer and effectively controlling membrane fouling (transmembrane pressure < 0.024 kPa·d⁻¹). The TUC-AnMBR exhibited exceptional process stability, underscoring the potential of shear-induced hydrodynamic optimization for energy-efficient wastewater treatment. This work advances the application of low-carbon anaerobic technology for treating refractory industrial wastewater.