Mathematical model analysis on the enhancement of aeration efficiency using ladder-type flat membrane module forms in the Submerged Membrane Bio-reactor (SMBR)

The cross-flow shearing action produced from the inferior aeration in the Submerged Membrane Bio-reactor (SMBR) is an effective way to further improve anti-fouling effects of membrane modules. Based on the widely-applied vertical structure of flat membrane modules, improvements are made that ladder-type flat membrane structure is designed with a certain inclined angle θ so that the cross-flow velocity of bubble near the membrane surface can be held, and the intensity and times of elastic collision between bubbles and membrane surface can be increased. This can improve scouring action of membrane surface on aeration and reduce energy consumption of strong aeration in SMBR. By deducing and improving the mathematics model of collision between bubble and vertical flat put forward by Vries, the relatively suitable incline angle θ under certain aeration place and in certain size rang of bubble can be obtained with the computer iterative calculation technology. Finally, for many groups of ladder-type flat membrane in parallel placement in the practical application of SMBR, some suggestions are offered: the interval distance of membrane modules is 8–15 mm, and aeration should be operated at 5–7 mm among membrane modules, and the optimal design angle of trapeziform membrane is 1.7°-2.5°.

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