USING A TWO-PHASE HYDRODYNAMIC MODEL TO CONTROL FOULINGIN AN ULTRAFILTRATION SIDE-STREAM MBR

摘要

A common problem encountered with membrane bioreactors (MBRs) systems is foulingrnof the membrane resulting in frequent cleaning and replacement which makes the systemrnless appealing for full-scale applications. This hammers its commercialization due tornreduction of productivity and increased maintenance and operational cost. Literature hasrnshown that the hydrodynamics near the membrane surface have an impact on fouling. Arntwo-phase hydrodynamic model was implemented in Fluent (Ansys, USA) using thernVolume of Fluid (VOF) approach to simulate the slug flow inside the tubular membranernand to predict the shear rates near the wall. The model is used to determine optimal gasrnflow rate requirements in terms of pressure drop across the membrane tube. Therneffectiveness was evaluated through relating these inputs with apparent shear stressesrnnear the membrane surface. The latter can be expressed as shear stress distributionsrn(SSD). A range of gas-air flow rate mixtures were investigated and resulted in differentrnSSDs.