• Membrane Journal
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• v.23 no.1
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• pp.70-79
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• 2013

The $N_2$ back-flushing period (FT) and time (BT) were investigated in hybrid process of ceramic microfiltration and PES (polyethersulfone) beads loaded with titanium dioxide ($TiO_2$) photocatalyst for advanced drinking water treatment in viewpoints of membrane fouling resistance ($R_f$), permeate flux (J), and total permeate volume ($V_T$). As decreasing FT and increasing BT, $R_f$ decreased and J increased, and finally the maximum $V_T$ could be acquired at FT 10 min and BT 30 sec. In FT effect experiment, treatment efficiencies of turbidity and dissolved organic matters (DOM) were the highest at no back-flushing (NBF) because of dramatic membrane fouling. As result of BT effect, the treatment efficiencies were the maximum at BT 30 sec, which was different with the FT result. Because the photocatalyst beads could be cleaned effectively as decreasing FT and increasing BT, turbidity treatment efficiency increased a little from 95.4% to 97.5% as decreasing FT, and from 95.9% to 98.5% as increasing BT. Also DOM treatment efficiency increased from 70.8% to 80.6% as decreasing FT, and from 75.1% to 85.8% as increasing BT. The optimal condition, where the treatment efficiencies and $V_T$ were the maximum, should be FT 10 min and BT 30 sec in our experimental range.

• Membrane Journal
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• v.23 no.3
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• pp.226-236
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• 2013

The effect of $N_2$ back-flushing period (FT) and time (BT) was compared with the previous result used PES (polyethersulfone) beads loaded with titanium dioxide photocatalyst in hybrid process of alumina microfiltration and PP (polypropylene) beads coated with photocatalyst in viewpoints of membrane fouling resistance ($R_f$), permeate flux (J), and total permeate volume ($V_T$). The reason of nitrogen back-washing instead of the general air back-washing method is to minimize the possible effect of oxygen included in air on water quality analysis. As decreasing FT, $R_f$ decreased and J and $V_T$ increased. Treatment efficiency of dissolved organic matters (DOM) was 82.0%, which was the higher than 78.0% of the PES beads result. This means that PP beads coated with photocatalyst was the more effective than PES beads loaded with photo-catalyst in the DOM removal. As increasing BT, the final $R_f$ decreased and the final J increased, but $V_T$ was the maximum at BT 15 sec. The average treatment efficiency of turbidity did not have any trend as changing BT. As BT increasing from 6 sec to 30 sec, the treatment efficiency of DOM increased 11.8%, which was a little higher than the result of PES beads.