Comparison of biofilm cell quantification methods for drinking water distribution systems

Due to variability in results obtained from each method, multiple methods are recommended to assess biofilm growth in drinking water distribution systems. Of the methods investigated here, HPC and CLSM and recommended for further development towards application in full-scale systems. HPC is a sample and widely applied method that quantifies viable culturable cells. CLSM analysis allows the elimination of experimental variables associated with cell detachment and affords the opportunity to evaluate biofilm components such as extracellular polymeric substances through the addition of specific probes. These two methods can be applied together to assess biofilms known to degrade treated water quality during conveyance in full-scale drinking water treatment systems. The significance of improved biofilm assessment methods for drinking water distribution systems lies in advancing understanding of biofilm growth and control mechanisms that may lead to improved water quality during conveyance and at the tap for greater public health protection.