title: Biofouling control: Bacterial quorum quenching versus chlorination in membrane bioreactors.
abstract: Biofilm formation (biofouling) induced via cell-to-cell communication (quorum sensing) causes problems in membrane filtration processes. Chorine is one of the most common chemicals used to interfere with biofouling; however, biofouling control is challenging because it is a natural process. This study demonstrates biofouling control for submerged hollow fiber membranes in membrane bioreactors by means of bacterial quorum quenching (QQ) using Rhodococcus sp. BH4 with chemically enhanced backwashing. This is the first trial to bring QQ alongside chlorine injection into practice. A high chlorine dose (100 mg/L as Cl2) to the system is insufficient for preventing biofouling, but addition of the QQ bacterium is effective for disrupting biofouling that cannot be achieved by chlorination alone. QQ reduces the biologically induced metal precipitate and extracellular biopolymer levels in the biofilm, and biofouling is significantly delayed when QQ is applied in addition to chlorine dosing. QQ with chlorine injection gives synergistic effects on reducing physically and chemically reversible fouling resistances while saving substantial filtration energy. Manipulating microbial community functions with chemical treatment is an attractive tool for biofilm dispersal in membrane bioreactors.
authors.affiliation: Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea; Department of Engineering Technology, Faculty of Technology, University of Sri Jayewardenepura, Gangodawila, Nugegoda 10250, Sri Lanka.
authors.forename: Nuwan A
authors.initials: NA
authors.lastname: Weerasekara
authors.affiliation: Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea. Electronic address: chookh@knu.ac.kr.
authors.forename: Kwang-Ho
authors.initials: KH
authors.lastname: Choo
authors.affiliation: School of Chemical and Biological Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
authors.forename: Chung-Hak
authors.initials: CH
authors.lastname: Lee
mesh_terms: D018441:Biofilms; D057219:Biofouling / Q000517:prevention & control*; D019149:Bioreactors / Q000382:microbiology; D054879:Halogenation; D008567:Membranes, Artificial; D053038:Quorum Sensing
chemical_list: D008567:Membranes, Artificial
keywords: Biofouling; Cell communication; Chlorination; Quorum quenching; Signal molecule