Ultrafiltration of biologically treated domestic wastewater: How membrane properties influence performance

Abstract

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Ultrafiltration of biologically treated domestic wastewater AbstractIn this study, the impact of membrane properties on membrane fouling and permeate water quality was investigated. Short-and long-term laboratory scale experiments using four commercially available hollow fiber UF membranes were performed to study the impact of membrane properties on reversible and irreversible fouling. No significant differences in terms of permeate quality (i.e. biopolymer rejection) were observed over the four tested membranes. It was found that membrane characteristics including pore size, pore distribution and especially materials had a strong impact on the filtration performances in terms of both reversible and irreversible fouling. The short-term filtration tests showed that due to its specific hydrodynamic condition only the inside-out mode UF membrane was subjected to irreversible fouling. These data demonstrate the importance of membrane selection with appropriate operating conditions for optimum performances. The added value of membrane characterization to lab-scale filtration tests for membrane performance was discussed.

Theoretical and Computational Analysis on Double-End Submerged Hollow Fibre Membrane Modules

“…As these modules are also connected to suction pumps through the permeate outlet, the resulting pressure difference between the wastewater catchment's hydrostatic pressure and the pumps' suction pressure drives the flow of water through the hollow fibres in an outside-in configuration, where water enters from the membrane surface, into the fibre lumen, and exiting from the fibre end. The outside-in configuration is more widely used in wastewater treatment due to better reversibility of fouling as compared to the inside-out configuration [18]. As such, this configuration is used as an assumption for the hollow fibre model used in this paper.…”

“…It was noted that the interpretation of permeability is different between the CFD model and the referenced paper. In this paper, the currently used CFD model's permeability is defined as a material's ability to allow fluid to pass through and is measured in m 2 based on Darcy's law [18], while the referenced paper derives a hollow fibre's permeability (in m 3 /Pa•s) as an empirical value which correlates the TMP (pressure difference) to the permeate output flow rate from experimental data. Due to differences in the interpretation of permeability between the current CFD model and the reference paper, the documented permeability of 10 −12 m 3 /Pa•s is translated using Darcy's law to achieve the correct value used in the CFD model.…”

“…λ, which is characteristic of the fibre geometry, is found to have a positive correlation with permeate pressure. This is because membrane permeability and wall thickness directly impact the influx of water going through the membrane wall [18], since the pressure difference required is a direct function of the volumetric flow rate within the lumen. The same can be said concerning the membrane inner diameter, as a larger diameter will reduce the pressure difference required [18].…”

“…This is because membrane permeability and wall thickness directly impact the influx of water going through the membrane wall [18], since the pressure difference required is a direct function of the volumetric flow rate within the lumen. The same can be said concerning the membrane inner diameter, as a larger diameter will reduce the pressure difference required [18]. With higher permeate pressure, fibres with higher λ values experience a greater permeate pressure drop in double-end suction.…”

Membrane Processes

“…As cake layer resistance is a key criterion in the resistancein-series model, the study recommended a standardized method for cake layer removal in order to correctly interpret the fouling phenomena with the resistance-inseries model. Filloux et al (2014) . Membrane fouling control in a submerged anaerobic membrane sponge bioreactor using an integrated rotary disk was investigated by and…”