Ridding tap water of bacteria with chemicals is a common practice in America, but one Biodesign Institute researcher is finding benefits to putting the bacteria back in.
The use of microbial agents to decontaminate tap water has long been the standard in Europe, but an American bias against bacteria has led to the use of chemicals to treat water instead, said Bruce Rittman, director of the Center for Environmental Biotechnology in the Biodesign Institute.
“We’re trying to manage the microorganisms to do the job we want them to do, and be happy about it,” Rittmann said Monday in a lecture on the Tempe campus.
As the director of the Center for Environmental Biology, Rittman researches biological methods that can be used to address some of society’s most important and intriguing challenges, like how to better ensure the decontamination of tap water.
In America, water from the tap must contain at least one milligram of chlorine, but in Europe it cannot contain more than one-tenth of a milligram. Using microbial agents or bacteria is a natural, chemical-free way to purify tap water, Rittman said.
“It turns out that what the microorganisms call food, we call pollution,” he said.
As worldwide concern for the safety of drinking water grows, Rittmann said the best way to approach the issue is to use the already-existing organic bacteria as a filter — an opinion he expressed in a research paper in 1984.
In the lecture, Rittman addressed the short-term risks associated with bacteria in drinking water that cause illness or death quickly, such as cholera or amoebic dysentery.
He contrasted those risks with the long-term risks of drinking chemically treated water, which include cancer, reproductive problems and neurological problems from the accumulation of exposure to low levels of chemicals.
The short-term risks of bacteria in drinking water are mostly protected against by what Rittmann calls the “four barriers of safety.” However, the long-term risks of chemicals in the drinking water have not yet been explored, he said, mostly because source water recently has been contaminated by extensive agricultural use of land.
One example is the recent appearance of high levels of nitrogen in drinking water. This is a result of farming, Rittman proved in a recent experiment sponsored by the city of Glendale, and is an issue that can be solved by filtering the water through microbial agents that feed on nitrogen.
Rittmann also warned against heavy reliance upon chemical disinfection and shocked the audience with a story of contaminated tap water in Milwaukee that left 400,000 people sick and killed 100 in 1993.
“This is America,” he said. “People aren’t supposed to get sick from tap water.”
Sustainability freshman Jaleila Brumand, a member of the ASU chapter of Take Back the Tap, a national student organization that encourages people to drink tap water in support of raising public awareness about the environmental dangers of using plastic bottles, said Rittmann’s research is a great cause.
“We need to use more processes that mimic nature,” she said.
Reach the reporter at npmendo@asu.edu
