Effect of powdered activated carbon (PAC) and cationic polymer on biofouling mitigation in hybrid MBRs

In this study, the influence of powdered activated carbon (PAC) and cationic polymer (MPE50) was investigated on the fouling propensity in hybrid MBRs. Three laboratory scale MBRs were operated simultaneously including MBRControl, MBRPAC, and MBRPolymer. Optimum dosages of PAC and polymer to the MBRPAC and MBRPolymer, respectively were determined using jar tests. It was found that the MBRPAC exhibited low fouling tendency and prolonged filtration as compared to the other MBRs. Improved filtration in MBRPAC was attributed to the flocculation and adsorption phenomena. The effective stability of the biomass by PAC in the form of biological activated carbon (BAC) was verified by the increase in mean particle size. The BAC aided sludge layer exhibited porous cake structure resulting in the prolong filtration. However, both the membrane hybrid systems revealed effective adsorption of organic matter by 40% reduction in the soluble EPS concentration.

► Hybrid membrane bioreactor with PAC (MBRPAC) exhibits prolong filtration performance.
► Cake layer resistance was lower in MBRPAC as compared to the other MBRs.
► PAC forms incompressible and porous cake layer structure over membrane fibers.
► Soluble biopolymers (EPS) adsorbed by PAC as well as cationic polymer in hybrid MBRs.