MORE | Summer 2022

Testing the Effect of Water Temperature and Disinfectants on Biofilm Formation by Different Bacteria in Different Pipe Materials

Health icon, disabled. A red heart with a cardiac rhythm running through it.

With the increase in world population, waterborne diseases are also increasing. Drinking water distribution systems (DWDS) biofilms can harbor pathogens, and opportunistic pathogens such as Legionella spp. and E. coli potentially release them back into the water, resulting in human exposure. In addition, water quality conditions can affect water pipes and water mains due to corrosion of metal surfaces which can be enhanced by the activity of sulfate-reducing and other bacteria in these biofilms. Therefore, we constantly need new and improved methods and treatments to bridge the gap in improving our understanding of the DWDS microbiome.

One way to increase biofilm and biomass quantity and get a more diverse community is the presence of chlorine residual to suppress biofilm accumulation. However, biofilms in drinking water distribution systems could exacerbate pathogens, bacteria persistence, and associated risks. This research aims to detect Legionella, E. Coli, and heterotrophic bacteria in the biofilms formed in a bioreactor system with three pipe materials like Stainless Steel, Copper, and Cross-linked polyethylene (PEX); using different disinfectants to eliminate biofilm or prevent biofilm from further growth while measuring the effect of temperature on formation, in each pipe, by using standard aquarium heaters.

The positive results of biofilm reduction through water distribution systems will play a key role in improving the world’s water safety, lessening contamination, and improving sustainability.

Student researcher

Bita Kolahi Kouchaki

Environmental engineering

Hometown: Phoenix, Arizona, United States

Graduation date: Fall 2022