Evaluation of chlorine dioxide (ClO₂) for the control of biofilms

A continuous culture chemostat model was used to simulate a flowing water pipe system such as those found in buildings. A primary vessel was set up to grow an inoculum that would represent a water storage tank feeding secondary and tertiary vessels downstream that simulated the water system. Filter-sterilised tap water was used as the growth medium in the continuous culture vessels with no exogenous carbon sources. In addition, the microbial culture consisted of a mixed consortium obtained from a potable water system. Secondary and tertiary vessels enabled the biofilms to be formed before being challenged with appropriate biocides. Even when testing the efficacy of the different biocides, the vessels were still being challenged with the microbial consortium which was constantly flowing from the primary reservoir vessel. This configuration ensured the reproducibility of the model when testing to destruction in the secondary vessels. The flexibility of the system enabled chlorine dioxide to be tested.