Effect of dissolved oxygen concentrations on the operational efficiency of the powdered activated carbon-membrane bioreactor (PAC-MBR) and single membrane bioreactor (MBR)

Two experimental devices, namely, a powdered activated carbon (PAC)–membrane bioreactor (MBR) system and a single MBR system, were simultaneously operated under identical conditions. The changes in the dissolved oxygen (DO) concentration were observed in three phases. The removal efficiency of conventional pollutants in the two reactors was comparatively analysed; results indicated that the removal efficiency of the PAC-MBR system is greater than that of a single MBR system because the addition of PAC enhances the biodegradation of activated sludge, which is treated as a carrier for the adherence and growth of microorganisms and the adsorption of harmful substances. The DO concentration exerted lesser effects on the operational efficiency of PAC-MBR than on MBR. Moreover, the changes in the concentrations of proteins and polysaccharides in the two reactors were also examined. The protein concentration significantly changed, but that of polysaccharides did not change.