Evaluating the performance of an integrated membrane-aerated biofilm reactor (MABR) system for high-strength brewery wastewater treatment

Abstract

Brewing—a water-intensive industry—produces a significant amount of wastewater, requiring effective treatment before discharge to the terrestrial or aquatic ecosystem. The treatment efficacy of a single/two-stage membrane aerated biofilm bioreactor (MABR) coupled with a coagulation/flocculation (C/F) preprocess for high-strength brewery wastewater was investigated. The combined system effectively removed COD (89.1 ± 4.2%), nitrogen (66.7 ± 13.5%), and phosphorus (91.1 ± 9.5%) for different influent loads and operational conditions. The C/F process significantly reduced major loads of the subsequent MABR with a removal efficacy of 38.1–60.8%, 23.5–55.3%, and 76.8–90.1%, respectively, for COD, nitrogen, and phosphorus. In addition, the MABR exhibited a high treatment threshold for COD (>3400 mg COD per L) and achieved a COD removal rate ranging from 18 g m⁻² d⁻¹ to 64 g m⁻² d⁻¹. Next-generation sequencing revealed the dominance of a MABR biofilm with three different taxa (Bacteroidia, Actinobacteria, and Clostridia) with a cumulative relative abundance of 52.9 ± 19.9%. Among all biofilms, biosynthesis of amino acids (5.1% to 5.9%) and carbon metabolism (4.3% to 4.6%) were dominant KEGG pathways. Bacterial compositions and biofilm functionality were strongly dependent on airflow and COD loading rates, while the air flow rate was a crucial regulation factor in real-world applications. Altogether, this study demonstrated the potential implementation of MABR coupled with physicochemical processes for efficient removal of COD, nitrogen, and phosphorus from industrial wastewater (with high sugar contents), such as brewery, starch, and dairy wastewater.