| Summary: | The main objective of this project is to compare the performances of three types of fluidised media, namely granular activated carbon (GAC), plastic beads and APG biocarrier, in removing organic matter and membrane fouling reduction potential. The results showed that fresh GAC appeared to adsorb 65% of the soluble organic substances from the effluent of the pilot anaerobic fluidized biological reactor (AFBR), which was significantly more than fresh plastic beads and APG biocarrier (almost negligible adsorption capability).
Furthermore, the AFBR effluent was fed into a bench-scale anaerobic fluidized membrane bioreactor (AFMBR). After operation for 3 weeks, the biosorption/biodegradation removal efficiencies of soluble organic matter by the three fluidised media were studied. It was found that the biofilm attached on the fluidized GAC particles tended to adsorbed and degraded 74% of organic substances, which was more than those of plastic bead (71%) and APG biocarrier (54%) by the excitation-emission matrix (EEM) analysis. In order to study the soluble organic substances removal, the AFBR effluent was filtered and fed into the filtration cell. The EEM results illustrated that the biofilm attached on the GAC particles reduced 66% of soluble organic substances, but plastic beads and APG biocarrier only removed 45% and 56% respectively of soluble organic substances. In addition, LC-OCD analysis revealed that the biofilm attached on the fluidised GAC particles solely contributed to adsorb/degrade low molecular weight neutral substances rather than other greater-sized organic matters (such as biopolymers, humic substances, and building blocks). Indeed, more retention of biopolymers by membranes was observed.
Finally, the effect of tested fluidised media on membrane critical flux was tested in the bench-scale AFMBR. The results showed that the comparable membrane critical flux was noticed in the presence of GAC and plastic beads, which was higher than that of APG biocarrier. Overall, GAC is the most recommended fluidised media to be used in AFMBR due to its higher biosorption/biodegradation capability and more efficient membrane fouling control potential
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