Structural analysis and optimization of gravity-driven membrane (GDM) for water treatment using computational fluid dynamics (CFD) with open slot implementation

Abstract

Appropriate cleaning methods are essential to ensure the continuous use of membranes, however, research on the suitable cleaning methods for Gravity-driven membrane (GDMs) remains insufficient. To remove contaminants accumulated on the membrane surface of GDM modules, open slot and non-slot modules were designed and manufactured. These modules were compared for their filtration performance and contaminant removal efficiency through computational fluid dynamics simulations and filtration experiments using influent from wastewater treatment plants (WWTP). While the flow velocity in the housing of the open slot module is slower than that of the non-slot module, flow velocity of 0.17 m/s through the slot can effectively remove sludge accumulated near the beginning of the filtration area, thereby reducing the dead zone. Evaluation of the filtration performance of both modules using influent from WWTPs revealed that flushing effects occurred in both modules for the initial 100 L of filtration, but thereafter, flushing effects were observed only in the open slot module. Therefore, an introducing a slot structure can lead to significant cleaning effects compared to non-slot modules. Therefore, to maintain permeate flux continuously, it is deemed necessary to accompany an appropriate open-slot module for clean-in-place and chemical cleaning.