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 particl es may carry coliform and even pathogenic bacteria through the disinfe ction barrier. Such a breakthrough could have ail impact on distributi on system biofilms. Using total cell counts, specific monoclonal antib ody staining, and computerized image analysis, rye monitored the colon ization of introduced Klebsiella pneumoniae associated with carbon fin es in mixed-population biofilms. The particles transported the colifor ms to the biofilms and allowed successful colonization, Chlorine (0.5 mg/liter) was then applied as a disinfectant, Most ii, pneumoniae alon g with the carbon fines left the biofilm under these conditions, The i mpact of chlorine was greater on the coliform bacteria and carbon fine s than on the general bacterial population. However, 10% of the introd uced coliforms and 20% of the fines remained In biofilm. The possibili ty that this represents a mechanism far bacteria of public health conc ern to be involved in regrowth events is discussed.