Friday, January 11, 2008

Cedar Hill water quality, safety no drop in the bucket

By Steve Snyder of TODAY Newspapers

City water supplies may not be the most “sexy” subject in the world - until people hear about something wrong, or seemingly wrong.

Then, everybody perks up.

That was the case in early November, when the city announced routine water testing for the month had exceeded the Texas Commission on Environmental Quality's standards for coliform bacteria.

Studies have indicated the sexiness of discussing a water supply is directly proportional to the number of hot chicks laying near or frolicking within said supply.

The city is required to take at least 40 samples a month of its water supply. Of these, five October samples were found to contain coliform bacteria, as did two repeat samples. Per state regulation, more than 5 percent of samples testing positive is the benchmark for public notification.

But, Adam Campbell, operations manager of the city's public works department, explained that exceeding state standards on this test didn't equate to “failure.”

“Coliform bacteria is a naturally-occurring, harmless bacteria. It's an indicator organism,” he said. “It's an indicator there might be other bacteria.”

That is, the presence of coliform samples in a higher percentage than what is normal for the general environment may indicate the presence of other bacteria. However, it does not necessarily do so.

Campbell said the water testing procedure is very delicate and that an improperly sealed test container, or gusty wind or other weather conditions, can cause a false positive reading.

He explained what happened after the city water supply exceeded state standards on a required 40 test samples in November.

He said if a resampling also tests positive, then the water is tested for those other potential bacteria, such as the well-known E. coli.

If they are found, the public is notified immediately, rather than through a newspaper public notice, as with the coliform bacteria sample.

“If there had been anything beyond coliform, there would have been immediate public notice,” Campbell said.

Nothing further showed up. If nothing shows up a month after a coliform positive result, the city then posts an “all clear” newspaper public notice similar to the coliform one in the Nov. 22 Cedar Hill Today.

To make sure that there was no problem, even beyond the tight standards of state requirements, Campbell said his staff did additional sampling.

“We did approximately 20 additional tests to make sure there was no problem,” he said.

Campbell and Director of Public Works Ruth Antebi-Guten then described all the different tests done by both the city of Cedar Hill and Dallas Water Utilities, from where Cedar Hill gets its water supply.

Besides the monthly testing for coliform bacteria, the city tests quarterly for byproducts of the Dallas Water Utilities disinfection process, such as trihalomethanes and chloroform and total chlorine residue. It also tests on a three-year basis for lead and copper. Total chlorine content is tested daily to insure disinfectant levels. Dallas Water Utilities tests for nitrates, other disinfectant byproducts and water turbidity.

Antebi-Guten also talked about proactive water quality work the city was doing.

“We're working with (Dallas Water Utilities) to come up with additional treatment measures,” she said.

She explained that these could be mechanical measures, such as equipment or design work to increase circulation in city water tanks and towers and new methods for flushing pipes, or chemical measures, such as giving water a local “booster shot” of chlorine or other treatment chemicals.

With population growing in Cedar Hill and the entire metropolitan area Dallas Water Utilities serves, Antebi-Guten and Campbell know their work will become more challenging in the future with more water in the system and more demands on it.

“I expect the state to increase our testing from 40 to 50 samples per month,” Campbell said.

Because of continued growth, Antebi-Guten said Dallas Water Utilities has been meeting with a consultant for several months to determine new measures it may need to undertake in the future. She said Cedar Hill has been following this closely, to be ready itself to continue to more than adequately meet local water needs

Pegasus News content partner - TODAY Newspapers

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