Physico-chemical characterisation versus in situ micro-structural characterisation of membrane fouling in membrane bioreactors

摘要

Fouling characteristics of aerobic submerged membrane bioreactors were analysed under twondifferent membrane materials. Polyethersulfone (PES) membranes were found to foul faster atnsub-critical flux than polyolefin (PO) membranes. Physico-chemical characterisation, by meansnof comparison of extracellular polymeric substances (EPS) and soluble microbial products (SMP)nconcentrations, as well as the mixed liquor suspended solids (MLSS) concentration werenunable to explain the differences in membrane fouling of the contrasting membrane materials.nThe use of confocal laser scanning microscopy (CLSM) to image organic foulants directly on thenmembrane surface, coupled with image analyses showed that membrane fouling mechanismnshifted from a biofilm initiated process on PO membranes to a bio-organic dominated processnon PES membranes under sub-critical flux conditions. These results show that physico-chemicalncharacterisation of an MBR process may not effectively distinguish the effectiveness ofndifferent membrane materials, so long as operating conditions are identical, and thatncharacterisation of foulants on the membrane surfaces was necessary to elucidate thendifferences in membrane fouling.