Authors: EuiJong Lee YoungHoon Kim HyungSoo Kim Am Jang
Publish Date: 2014/12/30
Volume: 22, Issue: 11, Pages: 8451-8459
Abstract
Currently there is a growing emphasis on wastewater reclamation and reuse all over the world due to restricted water resources Among a variety of wastewater reuse technologies the use of microfiltration membranes MF is one of the popular processes because it has the ability to successfully eliminate particulates and colloidal matters However successful fouling control is not easy because effluents from the activated sludge process still contain small particulates and colloidal matters such as extracellular polymeric substance EPS and soluble microbial products SMP On the other hand microbubbles have advantageous properties compared to common bubbles but there hasn’t been reporting of the use of microbubbles in physical cleaning instead of aeration Encouraging results were obtained herein through the application of microbubbles for physical cleaning In evaluation of the cleaning efficiency the efficiency of microbubbles was observed to be twice as high as that of aeration except during the course of the initial 30 min Total organic carbon TOC concentration of the membrane tank after treatment with microbubbles was more than twice as high as that after aeration for physical cleaning The membrane cleaned with microbubbles also had the smoothest surface with a roughness of 425 nm In addition microbubbles were found to effectively remove EPS and make the structure of the gel layer loose In particular the microbubbles had the ability to remove proteins through the effect of pyrolytic decomposition Therefore in FTIR spectra of the membrane surfaces taken before and after physical cleaning while each treatment showed similar peak positions the peak values of the membrane treated with microbubbles were the lowest Through various analyses it was confirmed that microbubbles can remove foulants on the gel layer in spite of their very low shear force This means that microbubble cleaning has full potential for use as a physical cleaning method in the wastewater reclamation process
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