Two-phase flow in membrane processes: A technology with a future

The Performance and Fouling Control of Submerged Hollow Fiber (HF) Systems: A Review

“…Membrane fouling, the process by which foulants, namely colloidal (e.g., clays, flocs), biological (e.g., bacteria, fungi), organic (e.g., oils, polyelectrolytes, humic substances), and scaling (e.g., mineral precipitates in RO systems) foulants, deposit onto the membrane surface or in the membrane pores [72,73], may take different forms, the main mechanisms of which are adsorption (physical and/or chemical), pore blocking, deposition of a cake layer, and gel formation [74][75][76][77][78][79]. The extent of fouling, which stems from the nature of foulant-membrane interaction, is a complex function of the feed characteristics (e.g., foulant type, foulant concentration, and physicochemical properties of the foulants such as the functional groups, charge, size, and conformation [72,[80][81][82]), operating conditions (e.g., inadequate pretreatment, inadequate control of the hydrodynamics of the system, excessive flux, and low cross-flow velocity (in cross-flow systems) [72,[82][83][84]), and membrane properties (e.g., pore-size distribution, surface roughness, charge properties, and hydrophobicity [70,[85][86][87]). …”

“…Unsteady-state shear, such as two-phase flow (i.e., gas bubbles or fluidized particles) and vibration, is more energy-efficient than steady-state shear [123]. Air bubbling is particularly attractive in MBRs for aeration, mixing, and augmenting liquid flows [14,82,200,201].…”

“…The use of bubbly flow has been reviewed by Cui et al [14] and more recently by Wibisono et al [82]. The major benefit of rising bubbles is the unsteady or transient shear stress at the membrane surface that causes particle back-transport away from this surface [14,15,22].…”

CFD simulation and optimization of membrane scouring and nitrogen removal for an airlift external circulation membrane bioreactor

“…High and even distribution of shear stresses on different membrane surfaces were preferred for alleviating membrane fouling (Wibisono et al, 2014). With that, MBR can be maintained with a lower superficial airflow rate, which, in this study, was helpful for energy saving and to keep the DO concentration low in anoxic unit.…”

Hydrogel-coated feed spacers in two-phase flow cleaning in spiral wound membrane elements: A novel platform for eco-friendly biofouling mitigation

“…The presence of spacers in the membrane modules has a significant contribution to the occurrence of biofouling and especially the feed spacer is a source for biomass growth inducing befouling. Biofouling removal from membrane feed channels using two-phase flow was found effective and can be used as an environment and membrane friendly cleaning method (Wibisono et al 2014, Wibisono et al 2015.…”