title: Salt stress in a membrane bioreactor: dynamics of sludge properties, membrane fouling and remediation through powdered activated carbon dosing.
abstract: Membrane bioreactors are a well-established technology for wastewater treatment. However, their efficiency is adversely impacted by membrane fouling, primarily inciting very conservative operations of installations that makes them less appealing from an economic perspective. This fouling propensity of the activated sludge is closely related to system disturbances. Therefore, improved insight into the impact of fouling is crucial towards increased membrane performance. In this work, the disturbance of a salt shock was investigated with respect to sludge composition and filterability in two parallel lab-scale membrane bioreactors. Several key sludge parameters (soluble microbial products, sludge-bound extracellular polymeric substances, supramicron particle size distributions (PSD), submicron particle concentrations) were intensively monitored prior to, during, and after a disturbance to investigate its impact as well as the potential governing mechanism. Upon salt addition, the supramicron PSD immediately shifted to smaller floc sizes, and the total fouling rate increased. Following a certain delay, an increase in submicron particles, supernatant proteins, and polysaccharides was observed as well as an increase in the irreversible membrane fouling rate. Recovery from the disturbance was evidenced with a simultaneous decrease in the above mentioned quantities. A similar experiment introducing powdered activated carbon (PAC) addition used for remediation resulted in either no or less significant changes in the above mentioned quantities, signifying its potential as a mitigation strategy.
authors.affiliation: Wetsus Centre of Excellence for Sustainable Water Technology, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands; BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium. Electronic address: lieven.detemmerman@ugent.be.
authors.forename: L
authors.initials: L
authors.lastname: De Temmerman
authors.affiliation: BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: T
authors.initials: T
authors.lastname: Maere
authors.affiliation: Wetsus Centre of Excellence for Sustainable Water Technology, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands; Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: Temmink
authors.affiliation: Wetsus Centre of Excellence for Sustainable Water Technology, P.O. Box 1113, 8900 CC Leeuwarden, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Zwijnenburg
authors.affiliation: BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium. Electronic address: Ingmar.Nopens@ugent.be.
authors.forename: I
authors.initials: I
authors.lastname: Nopens
mesh_terms: D019149:Bioreactors; D002606:Charcoal / Q000737:chemistry*; D005374:Filtration; D010316:Particle Size; D012722:Sewage / Q000032:analysis*; D012965:Sodium Chloride / Q000032:analysis*; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000032:analysis
chemical_list: D002606:Charcoal; D012722:Sewage; D012965:Sodium Chloride; D062065:Wastewater
keywords: Activated sludge; Fouling remediation; Particle size distribution; Salt shock; Size exclusion chromatography; Submicron particle concentration