Effects of adsorbent cake layer on membrane fouling during hybrid coagulation/adsorption microfiltration for sewage organic recovery

Direct organic recovery is an alternative option for enhanced energy recovery to achieve energy self-sufficiency or even carbon neutrality for wastewater treatment plants. Previous research reported that hybrid coagulation/adsorption microfiltration is efficient in recovering sewage organics. However, the fouling mechanism of adsorbent cake layer, which was formed during hybrid organic recovery process, needs to be evaluated to develop an appropriate fouling control strategy. In this study, the effects of adsorbent cake layer on the irreversible fouling during actual sewage concentration were analyzed quantitatively. Filtration resistance analysis based on dead-end filtration experiments provided evidences that the existence of adsorbent cake layer prevented severe irreversible fouling. After three filtration cycles, the reduced irreversible fouling by cake layer was as high as 20.84 × 1010 m−1, which was nearly three times of the resistance 7.04 × 1010 m−1 when no cake layer existed. This confirmed that the adsorbent cake layer controlled fouling, demonstrating that hybrid coagulation/adsorption microfiltration as a promising process for sewage organic recovery.