A recent study published in Engineering presents a novel approach to wastewater treatment and membrane fouling mitigation. The research, led by Zhiwei Wang from Tongji University, focuses on the development of an electroactive biofiltration dynamic membrane (EBDM).
The increasing scarcity of freshwater resources and the need for more efficient wastewater treatment have driven the search for innovative solutions. Anaerobic membrane bioreactors (AnMBRs) have shown promise, but membrane fouling remains a significant challenge. Dynamic membranes (DMs) can help, but their fouling layer growth needs to be better managed. The EBDM aims to address these issues by integrating an electric field into the DM system.
The researchers established an anaerobic conductive dynamic membrane bioreactor to study the EBDM system. They compared an electrochemical anaerobic dynamic membrane bioreactor (E-AnDMBR) with a control anaerobic dynamic membrane bioreactor (C-AnDMBR) over a 240-day period. The E-AnDMBR was operated with an applied voltage, while the C-AnDMBR functioned without voltage.
The results were remarkable. The EBDM in the E-AnDMBR exhibited an ultralow fouling rate, with a transmembrane pressure of less than 2.5 kPa throughout the operation. It achieved a high COD removal efficiency of over 93% and maintained a turbidity of around 2 NTU in the effluent. Moreover, the methane productivity in the E-AnDMBR was 7.2% higher than that in the C-AnDMBR.
Morphological analysis revealed that the EBDM acted as an efficient biofilter with an ordered-clogging and step-filtered structure. The electric field modified the physicochemical properties of the biomass, reducing the fouling potential. For example, it decreased the zeta potential of the sludge, increased the floc size, and reduced the viscosity and EPS concentration.
The EBDM also had a significant impact on the microbial metabolism. Metagenomic sequencing showed that continuous electrical stimulation promoted the development of an electroactive fouling layer with enhanced microbial metabolic functionality. It increased the relative abundance of Geobacter on the anode, which facilitated extracellular electron transfer and methane production.
This study demonstrates that the EBDM system is a promising technology for wastewater treatment. It effectively controls membrane fouling, enhances effluent quality, and improves methane productivity. The findings contribute to a better understanding of the interactions between electric fields and electroactive biofilms, providing a new option for enhancing membrane performance in wastewater treatment systems.
The paper "Development of Electroactive Biofiltration Dynamic Membrane (EBDM) for Enhanced Wastewater Treatment and Fouling Mitigation: Unraveling the Growth Equilibrium Mechanisms of Fouling Layer," is authored by Chengxin Niu, Wei Shi, Zhouyan Li, Zhiwei Qiu, Yun Guo, Zhiwei Wang. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.02.003
