Biochar-mediated optimization of anaerobic membrane bioreactor: Dose-dependent membrane fouling mitigation and digestion enhancement via scouring-biological synergy

Xifang Tang; Shaowen You; Chengfan Jiao; Qian Li; Yu-You Li; Rong Chen

doi:10.1016/j.biortech.2025.132872

Biochar-mediated optimization of anaerobic membrane bioreactor: Dose-dependent membrane fouling mitigation and digestion enhancement via scouring-biological synergy

Bioresour Technol. 2025 Jun 22:435:132872. doi: 10.1016/j.biortech.2025.132872. Online ahead of print.

Authors

Xifang Tang¹, Shaowen You¹, Chengfan Jiao¹, Qian Li², Yu-You Li³, Rong Chen⁴

Affiliations

¹ Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China.
² Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International S & T Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China. Electronic address: qian.li@xauat.edu.cn.
³ Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 9808579, Japan.
⁴ Key Lab of Environmental Engineering, Shaanxi Province, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International S & T Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China.

PMID: 40555332
DOI: 10.1016/j.biortech.2025.132872

Abstract

Anaerobic membrane bioreactors (AnMBRs) incorporating biochar (BC) offer a promising solution for food waste (FW) treatment; however, further BC dosage optimization is needed. This study assessed the effects of BC on AnMBR performance through experiments with multiple BC dosages (0-20 g/L), computational fluid dynamics (CFD) simulations, and microbial analysis comparing the optimal dose (10 g/L) with the control group. Optimal BC addition at 10 g/L increased methane production, maintained chemical oxygen demand (COD) removal at > 98 %, and reduced transmembrane pressure by 53.6 %. CFD modeling revealed enhanced turbulence at this dosage (peak dynamic pressure 0.43 kPa), promoting foulant scouring while inhibiting extracellular polymeric substance (EPS) adhesion. Microbial profiling revealed that BC enriched Chloroflexi and Methanosaeta populations, promoting direct interspecies electron transfer (DIET) and upregulating genes associated with acetoclastic methanogenesis. Excessive BC (≥15 g/L) worsened fouling due to particle deposition. The findings suggest a BC dosage strategy to balance efficiency and fouling mitigation in AnMBR-based FW treatment systems.

Keywords: Anaerobic digestion; Biochar dosage; Biofouling; Dynamic pressure; Food waste.