Floes pore size

The microfilter pore size was found to be an important parameter for effective filtration of the ferric hydroxide floe particles. Tong (28) studied three pore sizes,... 

Microfiltration (MF), like ultrafiltration, is a pressure-driven membrane process. In the case of microfiltration, the pore size is typically in the 0.03- to O.l-pm range. In this range, individual bacteria and viruses will pass through the membrane. However, colloidal suspended sohds, floe particles, and parasite cysts are prevented from passing. No removal of dissolved solids is accomplished by microfiltration membranes. 

Application of CFD to describe air bubbling is an area of intense activity, with the effects of air flowrate, intensity, bubble shape, diameter and frequency of particular interest. The major purpose of modelling the behaviour of bubbles is to evaluate the shear stress on the membrane wall. However, the interactions between the particles and bubbles are stiU not clear. For example, how are the floe shape and size and EPS formation affected by air bubbling Both floes and extracellular polymeric substances (or extracellular polysaccharides, EPS) contribute to formation of the cake layer and may block the membrane pores, with the extent of fouling potentially affected by the size of any particulates present. Models for cake layer build up and the removal by shear are still not well developed. Moreover, it is unclear how accurately the viscosity of the sludge should be modelled. The viscosity of the sludge could affect the extent of shear experienced by the floes but the inclusion of viscosity models... 

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