title: Effects of spacer orientations on the cake formation during membrane fouling: Quantitative analysis based on 3D OCT imaging.
abstract: Spacer design plays an important role in improving the performance of membrane processes for water/wastewater treatment. This work focused on a fundamental issue of spacer design, i.e., investigating the effects of spacer orientations on the fouling behavior during a membrane process. A series of fouling experiments with different spacer orientation were carried out to in situ characterize the formation of a cake layer in a spacer unit cell via 3D optical coherence tomography (OCT) imaging. The cake layers formed at different times were digitalized for quantitatively analyzing the variation in the cake morphology as a function of time. In particular, the local deposition rates were evaluated to determine the active regions where the instantaneous changes in deposit thickness were significant. The characterization results indicate that varying the spacer orientation could substantially change the evolution of membrane fouling by particulate foulants and thereby result in a cake layer with various morphologies; the competition between growth and erosion at different locations would instantaneously respond to the micro-hydrodynamic environment that might change with time. This work confirms that the OCT-based characterization method is a powerful tool for exploring novel spacer design.
authors.affiliation: Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore. Electronic address: wyli@ntu.edu.sg.
authors.forename: Weiyi
authors.initials: W
authors.lastname: Li
authors.affiliation: Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore. Electronic address: THChong@ntu.edu.sg.
authors.forename: Tzyy Haur
authors.initials: TH
authors.lastname: Chong
authors.affiliation: Singapore Membrane Technology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore.
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Fane
mesh_terms: D019149:Bioreactors; D008567:Membranes, Artificial; D041623:Tomography, Optical Coherence; D062065:Wastewater; D018508:Water Purification
chemical_list: D008567:Membranes, Artificial; D062065:Wastewater
keywords: 3D imaging; Membrane fouling; Optical coherence tomography; Quantitative analysis; Spacer orientation