title: Alkali-assisted membrane cleaning for fouling control of anaerobic ceramic membrane bioreactor.
abstract: In this study, a chemically enhanced backflush (CEB) cleaning method using NaOH solution was proposed for fouling mitigation in anaerobic membrane bioreactors (AnMBRs). Ex-situ cleaning tests revealed that NaOH dosages ranging from 0.05 to 1.30mmol/L had positive impacts on anaerobic biomass, while higher dosages (>1.30mmol/L) showed inhibition and/or toxic impacts. In-situ cleaning tests showed that anaerobic biomass could tolerate much higher NaOH concentrations due to the alkali consumption by anaerobic process and/or the buffering role of mixed liquor. More importantly, 10-20mmol-NaOH/L could significantly reduce membrane fouling rates (4-5.5 times over the AnMBR with deionized water backflush) and slightly improve methanogenic activities. COD removal efficiencies were over 87% and peaked at 20mmol-NaOH/L. However, extremely high NaOH concentration had adverse effects on filtration and treatment performance. Economic analysis indicated that 12mmol/L of NaOH was the cost-efficient and optimal fouling-control dosage for the CEB cleaning.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China; Centre for Water Research, Department of Civil and Environmental Engineering, National University of Singapore, 7 Engineering Drive 1, Singapore 117576, Singapore.
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Mei
authors.affiliation: Centre for Water Research, Department of Civil and Environmental Engineering, National University of Singapore, 7 Engineering Drive 1, Singapore 117576, Singapore.
authors.forename: Pei Jun
authors.initials: PJ
authors.lastname: Quek
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Centre for Water Research, Department of Civil and Environmental Engineering, National University of Singapore, 7 Engineering Drive 1, Singapore 117576, Singapore. Electronic address: howyongng@nus.edu.sg.
authors.forename: How Yong
authors.initials: HY
authors.lastname: Ng
mesh_terms: D000468:Alkalies; D000693:Anaerobiosis; D019149:Bioreactors; D002516:Ceramics; D008567:Membranes, Artificial; D014865:Waste Disposal, Fluid; D018508:Water Purification
chemical_list: D000468:Alkalies; D008567:Membranes, Artificial
keywords: Anaerobic membrane bioreactor; Ceramic membrane; Domestic wastewater; Membrane fouling; Sodium hydroxide