Vibrating MBR with Settling Zone for High-Flux Domestic Wastewater Treatment: Enhanced Nitrogen Removal and Fouling Mitigation

Abstract

High-flux operation remains a major challenge in membrane bioreactor (MBR) applications due to membrane fouling. This study proposed an optimized hybrid vibrating ceramic MBR (VCMBR) with a settling zone (SZ) to achieve long-term high-flux (40 LMH) operation for domestic wastewater treatment compared to a conventional air-sparging ceramic MBR (ASCMBR). Results showed that the VCMBR could be operated at 40 LMH with excellent organics and ammonium removal and slowed membrane fouling for over 1 week without any backwash. The introduction of SZ into the VCMBR enhanced the average TN removal efficiencies up to 68.1%, which were much higher than 29.1% in the ASCMBR with SZ. Reversible and irreversible fouling were simultaneously reduced in the VCMBR due to significant reductions of the DOMs in the fouling layer. Importantly, membrane vibration without strongly scouring the biomass could reduce the extracellular polymeric substances (EPSs) release and restrict the fouling sources, leading to better fouling control. Additionally, SZ helped lower the biomass concentrations in the membrane separation area, inducing lower EPS concentrations and thus showing less fouling propensity in both MBRs. Overall, the synergetic effects on enhancing nitrogen removal and fouling mitigation by this energy-efficient VCMBR could potentially advance high-flux MBR technology for future decentralized wastewater treatment.