Many city drinking water systems add softening agents to keep plumbing free of pipe-clogging mineral buildup.
According to new research, these additives may amplify the risk of pathogen release into drinking water by weakening the grip that bacteria – like those responsible for Legionnaires’ disease – have on pipe interiors.
They are teeming with harmless microbial life and incidents of waterborne illness are rare.
Because of this, water treatment plants add chemicals called polyphosphates to dissolve the minerals to keep the scale buildup under control.” A recent study by co-author and civil and environmental engineering professor Wen-Tso Liu has shown that even with the addition of antimicrobial agents by water companies, the bacteria that grow on the mineral scale can reproduce to harmful levels in supplies that stagnate within indoor plumbing.
In a new study published in the journal Biofilms and Microbiomes, a team of University of Illinois engineers shows that the addition of anti-scalant chemicals cause the biofilms to grow thicker and become softer.
The analytical method, developed by Stephen Boppart, a professor of electrical and computer engineering and study co-author, allowed the team to quantify the effect that polyphosphate has on the strength of biofilms.
To reproduce what happens in engineered plumbing systems, the team used PVC pipe and groundwater from the Champaign-Urbana area source to grow biofilms.
“Of course, one solution could be to replace pipes once they become clogged with mineral buildup,” Nguyen said.
“But that would be a very expensive endeavor for public utilities and property owners in a country as large as the United States.” Nguyen believes that the most affordable and realistic solution will come through a better understanding of water chemistry, not by trying to kill all microbes, ripping out pipes or changing regulations.
“We will not be able to control how long a drinking water user will allow water to stagnate, but we can work to understand how the chemicals we add to our water interact with biofilms.” This article has been republished from materials provided by the University of Illinois.