Effect of powder activated carbon (PAC) addition on the performance of anaerobic dynamic membrane bioreactor (AnDMBR): Stratification analysis of dynamic membrane characteristics

Powdered activated carbon (PAC), proved to be an effective performance enhancer in membrane bioreactor studies, has yet been applied in anaerobic dynamic membrane bioreactors (AnDMBRs). A better understanding of dynamic membrane (DM) characteristics is important for optimizing AnDMBR performance. In this study, three AnDMBRs were operated for synthetic municipal wastewater treatment with PAC dosages of 0, 1, and 3 g/L. Particular efforts were devoted to understanding the DM characteristics in layers. It was found that PAC addition increased COD removal efficiency (10 %) and decreased DM filtration resistance (60 %). The extent of performance enhancement, particularly the decrease of DM filtration resistance, appears to be much more substantial in AnDMBR than aerobic DMBR. PAC addition significantly reduced the fouling potential of suspended sludge and consequently the filtration resistance of DM. Compared with inner DM layer, the outer DM layer exhibited relatively higher fouling characteristics, such as less porous structure, higher EPS content (mainly proteins), hydrophobicity, and relative abundance of biofouling-related bacteria. The positive effect of PAC addition on reducing DM fouling characteristics turned out to be more significant for outer DM layer, mainly because of its higher PAC content associated with the higher amount of small particles.