Flux flow and cleaning enhancement in a spiral membrane element, using continuous infrasonic backpulsing

Abstract

The effect of backpulsing, into the permeate space of a 2.5 inch spiral wrap membrane, on the prevention of fouling (flux enhancement) was investigated experimentally. These experiments were performed using a 500 mg•ℓ -1 dextrin solution and a 100 000 MCWO polypropylene membrane, with a feed pressure of 100 kPa and a cross-flow rate of 1 000 ℓ•h -1 . Experimental results showed that a backpulse with a duration of about 170 ms, a repeat frequency of 1 s and differential peak pulse pressure, measured at the outlet of the permeate space, of 38 kPa gave the best results for the parameters used in the current experiments. In this case the saturation flux with backpulsing was 82% of the clean water value and 3.9 times the saturation flux obtained with no backpulsing.

Predicting optimal back-shock times in ultrafiltration hollow fiber modules II: Effect of inlet flow and concentration dependent viscosity

“…This is usually ascribed to the formation of a cake-layer in microfiltration [15][16][17]. Of the papers mentioned previously [2,3,[6][7][8][9][10][11][12][13] concerns ultrafiltration. Here the highest flux reported when using back-shocking as compared to the long term flux without back-shocking was 3.9 times the long term flux [2].…”

“…As the average flux can be higher when using back-shocking as compared to the long term flux without back-shocking, the backshock technique is increasingly being used in membrane filtration as an in situ method used to avoid or decrease the negative influence of concentration polarization, fouling, or both, on the flux during membrane filtration [1][2][3][4][5][6][7][8][9][10][11][12][13]. Generally, it can be said that a larger effect is observed when back-shocking is applied in microfiltration as compared to ultrafiltration.…”

“…Of the papers mentioned previously [2,3,[6][7][8][9][10][11][12][13] concerns ultrafiltration. Here the highest flux reported when using back-shocking as compared to the long term flux without back-shocking was 3.9 times the long term flux [2]. The increase in flux in ultrafiltration is usually ascribed to the reduction of the effects of concentration polarization or even a gel-layer.…”