Colonization and disinfection of biofilms hosting coliform-colonized carbon fines

The documented release of carbon fines from granular activated carbon filters is a concern for drinking water utilities. since these particles may carry coliform and even pathogenic bacteria through the disinfection barrier. Such a breakthrough could have ail impact on distribution system biofilms. Using total cell counts, specific monoclonal antibody staining, and computerized image analysis, rye monitored the colonization of introduced Klebsiella pneumoniae associated with carbon fines in mixed-population biofilms. The particles transported the coliforms to the biofilms and allowed successful colonization, Chlorine (0.5 mg/liter) was then applied as a disinfectant, Most ii, pneumoniae along with the carbon fines left the biofilm under these conditions, The impact of chlorine was greater on the coliform bacteria and carbon fines than on the general bacterial population. However, 10% of the introduced coliforms and 20% of the fines remained In biofilm. The possibility that this represents a mechanism far bacteria of public health concern to be involved in regrowth events is discussed.