TY - JOUR
T1 - Advanced intermittent air delivery in a membrane biofilm reactor achieves full biodegradation of a Quaternary Ammonium Compound
AU - Zheng, Chen Wei
AU - Lai, Yen Jung Sean
AU - Luo, Yi hao
AU - Eustance, Everett
AU - Suzuki, Maya
AU - Collins, Hannah
AU - Muse, Christopher
AU - Rittmann, Bruce E.
N1 - Publisher Copyright:
© 2025 Elsevier B.V.
PY - 2025/4/1
Y1 - 2025/4/1
N2 - Effective biodegradation of Quaternary Ammonium Compounds (QACs) in wastewater treatment is a pressing challenge that requires innovative and cost-effective solutions. QACs are biodegraded aerobically, and utilizing the O2 from air is a means to lower operating costs. This study investigated advanced air delivery in the Membrane Biofilm Reactor (MBfR) for complete removal of a QAC. Four distinctly different O2-delivery methods were compared: pure O2 with closed-end membranes, air with closed-end membranes, air with continuous bleeding, and air with periodic venting. The O2-based and air-venting systems could achieve 100 % removal of 364 mg/L (1 mM) hexadecyltrimethyl-ammonium (CTAB), which was much better than air closed-end (52 % removal) and air bleeding (66 % removal). Increasing the frequency of venting led to higher CTAB removal rates, and the maximum chemical oxygen demand (COD) flux reached 5.6 g-COD/m2-d. Pseudomonas and Stenotrophomonas comprised more than 50% of the microbial community for all O2-delivery methods. Genes related to CTAB biodegradation, including monooxygenases (catA, catB, FMO, CMO and benC-xyzD) and choline trimethylaminelyase (cutC), were similarly abundant among the biofilms, suggesting consistent biofilms were formed in the MBfRs. This study reveals that periodic venting is a simple strategy for enabling air-based, bubble-free O2 delivery for biodegrading QAC in the MBfR.
AB - Effective biodegradation of Quaternary Ammonium Compounds (QACs) in wastewater treatment is a pressing challenge that requires innovative and cost-effective solutions. QACs are biodegraded aerobically, and utilizing the O2 from air is a means to lower operating costs. This study investigated advanced air delivery in the Membrane Biofilm Reactor (MBfR) for complete removal of a QAC. Four distinctly different O2-delivery methods were compared: pure O2 with closed-end membranes, air with closed-end membranes, air with continuous bleeding, and air with periodic venting. The O2-based and air-venting systems could achieve 100 % removal of 364 mg/L (1 mM) hexadecyltrimethyl-ammonium (CTAB), which was much better than air closed-end (52 % removal) and air bleeding (66 % removal). Increasing the frequency of venting led to higher CTAB removal rates, and the maximum chemical oxygen demand (COD) flux reached 5.6 g-COD/m2-d. Pseudomonas and Stenotrophomonas comprised more than 50% of the microbial community for all O2-delivery methods. Genes related to CTAB biodegradation, including monooxygenases (catA, catB, FMO, CMO and benC-xyzD) and choline trimethylaminelyase (cutC), were similarly abundant among the biofilms, suggesting consistent biofilms were formed in the MBfRs. This study reveals that periodic venting is a simple strategy for enabling air-based, bubble-free O2 delivery for biodegrading QAC in the MBfR.
KW - Air-based membrane biofilm reactor
KW - Bleeding delivery
KW - Intermittent venting delivery
KW - Quaternary Ammonia Compounds
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U2 - 10.1016/j.cej.2025.161301
DO - 10.1016/j.cej.2025.161301
M3 - Article
AN - SCOPUS:86000507099
SN - 1385-8947
VL - 509
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
M1 - 161301
ER -