Evaluation of PAC Effect in Integrated PAC/UF System for Surface Water Treatment

The effect of powdered activated carbon (PAC) on the hybrid PAC/UF (PAC applied in combination with the ultrafiltration membrane) system was investigated in this paper. Compared to UF system, in which no PAC was added, the membrane flux was improved from 58.58% to 69.59% in terms of J/J₀ value for 200 minutes´ filtration. In PAC/UF process, it is the fraction which cannot be adsorbed by PAC takes greater responsibility for membrane fouling, this fraction possesses the potential to cause more irreversible fouling, regardless of its low organic content. Analysis by technological apparatus revealed that the apparent molecular weight (AMW) of this fraction is less than 500Da or more than 10kDa, and the more than 10kDa part shows predominant, it is also easily retained on the membrane surface to produce fouling; Furthermore, this fraction exhibits almost positive Zeta potential, and can be preferentially absorbed by the negative membrane surface, so as to cause the relatively severe flux decline.