Tapwater and Terrorists: UI Finds Ways to Protect Water

Tapwater and Terrorists: UI Finds Ways to Protect Water
Tapwater and Terrorists: UI Finds Ways to Protect Water

June 5, 2003

Urbana - When President Bush began his campaign for a homeland security agency, he did so from a Kansas City location with an ominous backdrop--a water treatment facility on a busy street that was protected by only a rusty chain-link fence.

It was symbolism at work. But real concerns lie behind this symbolism--concerns that our tapwater constitutes a large, vulnerable target for terrorists.

To protect the system of pipes that crisscross the underground world beneath our cities, University of Illinois researchers are active on several fronts. They're working on sensors to detect biological agents, such as anthrax bacteria. They're finding better, more effective ways to kill dangerous microorganisms with combinations of disinfectants. And they're even doing work to protect specific water systems in high-visibility, high-risk buildings in major cities.

When it comes to a threat on our drinking water, biological agents, such as Bacillus anthracis (the bacterium that causes anthrax), are a much greater concern than chemical agents, such as cyanide or arsenic, said Benito Mariñas, U of I professor in civil and environmental engineering.

With chemicals, Mariñas said, terrorists would have to use much larger quantities, making them highly impractical. What's more, the water system would dilute any chemical, subsequently diluting its impact.

Of the biological agents, viruses do not pose a major risk because chlorine in the water system does a good job of killing them. But certain bacteria, most notably anthrax bacteria, are the chief concern, Mariñas said. Anthrax spores are highly resistant to chlorine.

Today, chlorine, in its free or combined form, is the only disinfectant being used in water distribution systems because other options have severe limitations. For instance, Mariñas said, ozone is highly effective in killing anthrax spores. Unfortunately, it doesn't last long in the system.

"You put ozone into the water distribution system and it's gone," he said. "It will react with the walls of the pipes. It will react with everything."

Mariñas is leading a group that is experimenting with combinations of different disinfectants, looking for ways to increase their effectiveness and even make it possible to destroy anthrax spores.

By combining various disinfectants, he is finding a "synergistic" effect. In other words, when you use two disinfectants together, their effectiveness is much greater than the combined effect of using each disinfectant alone.

The U of I began this research well before September 11, 2001, he said, but funding opportunities for this type of work has gone up dramatically since then, along with the sense of urgency.

"Two years ago, I would have said it would have taken at least a decade for these technologies to be commercially available," Mariñas noted. "But with the level of federal funding we have now, I think a breakthrough is going to happen much sooner."