Full Description

A mathematical model is developed that accounts for internal fouling of membranes due to solublemicrobial products during subcritical flux operation, and for supercritical flux fouling due to cake formationand compression. The model takes into account the filtration effect generated by the cake. A set ofdifferential equations is derived and solved numerically to obtain a description of cake formation andgrowth, removal of substrate due to cake-membrane behavior, change in membrane permeability overtime, increase in cake headloss over time, removal of soluble microbial products by the cake, and changeof transmembrane pressure over time. The model allows operational changes of membrane operationsuch as modifications of permeate fluxes e.g. membrane relaxation, modification of aeration rates,backflushing and changes in water quality variables during one run. The model adequately describesseveral commonly observed effects such as: exponential increase in transmembrane pressure due tohigh mixed liquor suspended solids, reduced fouling rates at increased aeration intensities, subcriticaloperation fouling, and the effect of increased particle size on the filterability of the microbial suspension. Theuse of mass flux as supposed to volume flux is proposed as a parameter for critical flux determination. Includes 16 references, figures.

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Edition: Vol. - No. Published: 03/01/2007 Number of Pages: 16File Size: 1 file , 410 KB