Assessment of fouling behaviour in submerged microfiltration system coupled with flocculation

Microfiltration coupled with flocculation has the potential to remove colloidal and dissolved matter and hence mitigate membrane fouling. This study investigates the effects of flocculation on the performance of submerged membrane microfiltration of kaolin suspension. The addition of the flocculent (ferric chloride: FeCl3) demonstrated better control of colloidal membrane fouling. The experimental results showed that trans-membrane pressure (TMP) development at optimal flocculent concentration was significantly less than it was with an unflocculated feed. In the case of 30 L/m2/h, TMP was reduced by 85% with optimum concentration of flocculent. A regression analysis conducted between cake resistance and particle deposition showed a low specific cake resistance with flocculent addition.