Dynamic multidimensional modelling of submerged membrane bioreactor fouling

• Fouling model that predicts distributed shear, cake and flux profiles.
• Shear distribution profile predicted via multiphase computational fluid dynamics.
• Model includes dynamic linking of flux and transmembrane pressure.
• Predicts fouling dynamics with a broad range of scenarios.

Existing membrane fouling models are limited to simple hydraulic profiles which is a limitation particularly for planar membranes. Here, we present a new model that allows for a distributed shear profile, with dynamic linking of flux and transmembrane pressure (TMP). Shear profile is calculated using a multi-phase computational fluid dynamic approach, and is applied to a distributed parameter model to simulate membrane fouling profile and flux distribution. This allows for simulation of complex flux-step experiments, or situations where non-uniform shear is present. The model was applied to filtration experiments conducted in a pilot-scale anaerobic membrane bioreactor treating slaughterhouse wastewater comprising 1950±250 mg/L total solids and was able to effectively fit experiments under dynamic critical flux conditions. Cake compressibility was a key parameter, and was estimated at 870±80 Pa. Non-uniform gas distribution decreased critical flux from 12 LMH to 8.5 LMH. This emphasises the importance of local flow conditions on membrane fouling behaviour and that performance can depend heavily on reactor configuration and hydraulics.

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