Understanding and Management of Holistic Water Quality and Legionella in Public Building Systems

This research aims to develop an understanding of how interventions designed to improve water quality in buildings can be used to mitigate Legionella pneumophila concentrations. Intervention methods can be described as any approach that can be used to improve microbial water quality. In order to provide a foundation of background knowledge, a literature review was conducted to identify similar studies and collect relevant and timely research similar to the subject. The information gathered from the literature review was used to structure the sampling process and parameters. Using the research collected from the literature review, a review table was created to summarize the differences in the studies conducted and to determine research gaps. To categorize the studies, intervention methods, contaminants addressed, and water quality meta-data were differentiated for each of the articles. For the purpose of the sampling process, the three interventions analyzed consist of flushing, water heater set point change, and both flushing and water heater set point change. The locations of the sampling consisted of the city drinking water inlet, the basement janitor's closet, basement shower, 2nd floor, 3rd floor, and 7th floor break rooms and restrooms of the Interdisciplinary Science and Technology Building IV at ASU. For the flushing intervention, the sampling results demonstrated an increase in free and total chlorine concentration post flushing which aligns with the research found in the literature review. In addition, it was observed that iron concentrations drastically increased for both the cold and hot water by flushing. There was a significant decrease detected for ATP concentrations post flush in the hot line. However through the sampling session, the flushing intervention did not yield statistically significant results for Legionella concentrations.