Operator error blamed for water contamination

May 2008

U.S. Water News Online

PHOENIX — A malfunction at a Scottsdale plant that resulted in a three-day water ban affecting nearly 5,000 customers is being blamed on operator error.

That's the conclusion of an investigation made for Motorola Inc. and other companies that were the source of the trichloroethylene contamination decades ago. The companies are paying for cleanup of the contaminated groundwater, including the treatment facility.

The malfunction occurred Jan. 15 at a plant owned and operated by the Arizona American Water Co. that treats groundwater contaminated with TCE, an industrial solvent and a suspected cancer-causing chemical.

A separate investigation made for Arizona American concluded the plant's systems and components were not designed or operated in an optimal manner.

The U.S. Environmental Protection Agency and the Arizona Department of Environmental Quality will review both reports.

A malfunctioning blower on one of three forced-air stripping towers used to remove TCE was cited as the problem.

That malfunction allowed untreated water from a well known as PCX-1 to flow into the public water supply. In addition, a trio of alarms failed to alert operators.

In a letter submitted with its report, Arizona American president Paul Townsley said the evidence does not reveal how the blower shut down, leaving the well pumping. Arizona American no longer uses PCX-1 as a water source.