Influence of suspended carrier on membrane fouling and biological removal of styrene and ethylbenzene in MBR

• Membrane fouling decreased significantly for MBR with the carrier.
• Density and dosage of carrier have significant impact on floc formation.
• Proteins in biomass EPS and cake layer was the dominant fouling factor.
• PS was more important than PN in biomass SMP as fouling factor.
• Presence of EB has little negative effect on STR biological removal.

In this study, the biological removal of styrene (STR) and ethylbenzene (EB) was investigated and the effect of carriers on the membrane fouling (MF) and the performance of two MBRs (with and without carrier) were examined. The flocculation ability, sludge particle size distribution (PSD), FTIR analysis, excitation-emission matrix (EEM) fluorescence spectroscopy, microscopic observations, microbial activities, microorganism population, filamentous bacteria, and sludge volume index (SVI) are considered to determine sludge characteristics. The results show that adding suitable dosage of carrier can reduce MF. It was also demonstrated that, biodegradation was the main mechanism for the STR in both reactors, especially MBR with the carrier. Besides, in the reactor with carriers the MF decreased and the flocculation ability increased while specific oxygen uptake rate (SOUR), soluble microbial product (SMP) and extracellular polymeric substance (EPS) decreased. Moreover, it was found that the EPSP is the main reason for MF and EPS was not as the main factor of the floc. The result obtained in the FTIR spectrum and EEM florescence spectroscopy agreed well with the EPS contents in cake layer. Therefore advanced technology of EEM are useful to examine cake compositions.

Figure optionsDownload as PowerPoint slide