Impending federal drinking water regulations and concerns about microbial contamination in its water supply underscored the Greater Cincinnati Water Works’ (GCWW) need to handle emerging microbial contaminants.

Malcolm Pirnie designed a disinfection planning project to evaluate the treatment barriers’ effectiveness against pathogens associated with waterborne illnesses. The Pirnie team collaborated with university experts to investigate UV disinfection as a potential additional treatment barrier, and evaluated the effect of sequential inactivation on disinfection by-product (DBP) formation and microbial regrowth.

The researchers identified UV disinfection addition as an effective approach to creating a multiple barrier for chlorine-resistant microorganisms. They also found UV and free chlorine effective for all bacteria, protozoa and viruses tested. GCWW can use this information to develop a UV system for its treatment plant, with multiple successful disinfectant barriers for treating the city’s water.