Analysis and control of biofilms in a model drinking water system

Abstract

Biofilms existing in the drinking water distribution system affect the biostability of water. Conventional disinfecting strategies are not effective sufficiently for biofilm control. In this project, a preliminary survey was conducted to investigate the biofilm situation in a local drinking water distribution system. Thereafter, an annular reactor system, which could simulate the condition of the drinking water distribution system, was set up. A series of biofilm analysis methods, including biofilm sampling, heterotrophic plate counts, total carbohydrates content test, epifluoresence microscopy (LIVE/DEAD kit), and scanning electron microscopy , were adopted and modified. The biofilm control abilities of three different chlorine based agents (free chlorine, monochloramine, and free chlorine a?? silver ion combination) and three alternative high slug dose strategies were compared.