Biofilm detachment by self-collapsing air microbubbles : a potential chemical-free cleaning technology for membrane biofouling
Ng, Wun Jern
Date of Issue2012
School of Civil and Environmental Engineering
Microbubbles (MBs) have been known for their ability to generate pressure waves through shrinking and subsequent self-collapsing phenomenon. In the present study, we have investigated the potential of air MBs for biofilm detachment from a nylon membrane surface in comparison to chemical cleaning by sodium hypochloride (NaOCl). About 88% of fixed biomass detachment was observed after 1 h air microbubbling, while only 10% of biofilm detachment was achieved in the control experiment without microbubbles. Images taken with a confocal laser scanning microscope (CLSM) clearly showed that nearly all extracellular polysaccharides and proteins in biofilms were removed from the membrane surface, indicating a complete disruption of the extracellular polymeric matrix of biofilms. It was further demonstrated that microbubbling is much more efficient than chemical cleaning with 0.5% NaOCl solution in terms of removal of fixed biomass and extracellular polysaccharides and proteins. This study provides experimental evidence showing that self-collapsing air MBs is a chemical-free and eco-friendly technology for biofilm detachment.
Journal of materials chemistry
© 2012 Royal Society of Chemistry.