Transport of Enterococcus faecalis in granular activated carbon column: Potential energy, migration, and release

An increasing number of water purification plants use granular activated carbon filtration as an advanced treatment technology. One of the main constraints of carbon filtration is bacterial leakage, which can impact public drinking water safety. In this study, Enterococcus faecalis, commonly detected in natural water, was employed as the target bacteria for investigating the mechanism of deposition and migration of bacteria in granular activated carbon medium. The repulsive barrier, secondary potential well and potential energy change curve under various conditions were depicted by DLVO theory. Moreover, the influence, including ionic strength, ionic charge and flow rate, on bacterial transport was comprehensively discussed. The Enterococcus faecalis penetration curve was in accordance with the van der Waals force and electrostatic repulsion force under different conditions. Finally, 8%-11% of Enterococcus faecalis was released into the effluent when ionic strength declined.