Bacterial attachment and detachment in aluminum-coated quartz sand in response to ionic strength change

Column experiments were performed to investigate the effect of ionic strength on the attachment and detachment of Staphylococcus aureus ATCC 10537 and Bacillus subtilis ATCC 6633 in aluminum-coated quartz sand. Results showed that the average mass recovery decreased from 80.7 to 45.3% in quartz sand and remained constant in aluminum-coated sand with increasing ionic concentrations of sodium chloride solution from 1 to 100 mmol/L. As the ionic concentrations of leaching solution changed from 100 to 0.1 mmol/L, average mass recovery of 39.1% was obtained from quartz sand (bacterial release), but no detachment was observed from aluminum-coated sand. This lack of detachment can be attributed to inner-sphere complexes between bacteria and aluminum-coated sand, which are minimally affected by ionic strength. This research indicates that aluminum-coated sand has advantages over quartz sand in bacteria removal in water filtration systems.