Hydrodynamic optimization of membrane bioreactor by horizontal geometry modification using computational fluid dynamics

Numerical simulation of scaling-up for AEC-MBRs regarding membrane module configurations and cyclic aeration modes

“…In baffled MBRs, the baffles divide the membrane tank into riser zone and downcomer zone, create an internal circulation and a regular cross flow on the membrane surfaces due to the difference in gas holdup and bulk density in different zones. Baffles were proved to useful for the reduction of membrane fouling for lab-scale MBRs both in simulations and experiments (Krzeminski et al, 2017;Yan et al, 2016). The results of lab-scale study in this study were consistent with the above observations.…”

“…In fact, a lower ratio of crosssectional area of the riser to that of the downcomer A r /A d would generate a higher liquid velocity of the riser, U Lr . Yan reported that the average riser velocity increased with decrease of A r /A d when it was lower than 0.75, and a ratio of 0.17 was considered to be favorable in their bench-scale study with only one membrane sheet installed (Yan et al, 2016). However, the increase of downcomer area results in higher local resistance loss at the bottom connecting section, which will finally decrease the overall recirculation rate due to the energy dissipation (Chisti et al, 1988(Chisti et al, , 1995.…”

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

“…An average shear stress of 0.5 Pa in a full scale MBR was reported while an average shear stress of 0.6-0.7 Pa in a pilot scale MBR can be achieved with the dosing of flocculent, Fe (II) (Liu et al, 2015). The average membrane shear stress can be 0.5-2.0 Pa with SAD m = 0.5-9.0 m 3 m À2 h À1 in a lab-scale MBR (Yan et al, 2016(Yan et al, , 2015. In this study, the shear stress of 0.9 Pa at SAR 25 (SAD m = 1.0 m 3 m À2 h À1 ) was achieved.…”

Outlining the Roles of Membrane-Foulant and Foulant-Foulant Interactions in Organic Fouling During Microfiltration and Ultrafiltration: A Mini-Review

“…In UF processes, the enhancement could be achieved by increasing crossflow intensity, injecting gas to the membrane unit to produce secondary flow and wake flow, equipping movable parts to promote turbulence, and applying spiral flow with high rotation frequency to disturb the mass transfer boundary layer (Cabassud et al, 2001;Adach et al, 2002;Zakrzewska-Trznadel et al, 2009;Kondo et al, 2010). In MBR wastewater treatment processes, the hydraulic enhancement includes optimization of membrane aeration intensity, aerator type and layout, membrane module configuration, membrane cassette layout, and upflow/downflow circulation in the membrane tank (Drews et al, 2008;Yan et al, 2016;Wu et al, 2018). Computational fluid dynamics (CFD) reveal that setting baffles in an airlift MBR tank could constraint the upflow surrounding the membrane unit, elevate the average shear force on the membrane surface, and improve the uniformity of shear distribution to mitigate foulant deposition on the membrane surface (Yan et al, 2015(Yan et al, , 2016.…”

“…In MBR wastewater treatment processes, the hydraulic enhancement includes optimization of membrane aeration intensity, aerator type and layout, membrane module configuration, membrane cassette layout, and upflow/downflow circulation in the membrane tank (Drews et al, 2008;Yan et al, 2016;Wu et al, 2018). Computational fluid dynamics (CFD) reveal that setting baffles in an airlift MBR tank could constraint the upflow surrounding the membrane unit, elevate the average shear force on the membrane surface, and improve the uniformity of shear distribution to mitigate foulant deposition on the membrane surface (Yan et al, 2015(Yan et al, , 2016.…”