Enhanced anti-fouling performance in Membrane Bioreactors using a novel cellulose nanofiber-coated membrane

Abstract

• The fouling of TFNC-CNF membranes is reversible when filtering wastewater. • Enhanced flux was achieved in the submerged TFNC-CNF membrane bioreactor. • TFNC-CNF membranes showed higher rejection potential of bio-foulants. • Air scouring enhanced the flux of TFNC-CNF membranes when filtering wastewater. The filtration performance, fouling and flux recovery efficiency of a novel thin film nanofibrous composite-cellulose nanofiber (TFNC-CNF) coated membrane was studied and compared with polyvinylidene fluoride (PVDF) membranes treating domestic wastewater. The enhanced anti-fouling property of the TFNC-CNF membrane was associated with the super-hydrophilic nature and negative charge on the membrane surface. The dead-end cell filtration tests demonstrated the TFNC-CNF membrane recovered more than 90% of the initial flux after mechanical cleaning, compared with 26–43% recovery by PVDF membranes. Continuous wastewater ultrafiltration tests with mechanical air scouring confirmed the outstanding permeability (71.3–138.9 LMH/bar) and the superior anti-fouling characteristics (59.2–86.8% recovery of the initial flux) of the TFNC-CNF membrane. Furthermore, higher total organic carbon rejection rates were also observed in the TFNC-CNF membrane (>83.2%) than the PVDF membrane (<69.8%). Collectively, the superior flux recovery and high permeability makes the TFNC-CNF membrane a promising material for membrane bioreactors.