Town Water Treatment System Shut Down

Ground water contaminated by gasoline additive


A ground water clean-up project that was pumping 75 gallons a minute of drinkable water into town stores has been stopped temporarily because high levels of a gasoline additive have been found in the water.

The town and the Arizona Department of Environmental Quality have been filtering ground water that's tainted with dry-cleaning solvent through a treatment plant in south Payson to purify it.

The gasoline additive, methyl tertiary butyl ether, or MTBE, was discovered Sept. 1 and the plant was closed Sept. 2.

Long-term exposure to MTBE at levels above 35 micrograms per liter can cause health problems, said Michael Nesky, the project manager of the Payson site for ADEQ.

The water is tested before it enters the system, while it's in the system and at drinking-water test sites, he said. The testing system is programmed to warn operators if MTBE levels go above 17 micrograms per liter, which they did in August. The town received the test results Sept. 1 and operators shut down the plant the next day.

"We set the trigger level (at 17) because we did not even want to come close to those (maximum) levels," he said.

Preliminary test results indicate that the plant will be back on line and producing drinkable water by the end of next week, Payson Public Works Director Buzz Walker said.

The town and ADEQ built the interim ground water treatment system to monitor and remove the dry-cleaning solvent tetrachloroethylene from the ground water in the area, ADEQ spokesman Bruce Clendenning said.

The solvent was found in high concentrations in 1990 in two unused town wells near Aero Drive. The treatment plant was completed in 1997 to treat the contaminated ground water.

The contamination plume's underground boundaries range roughly from Frontier Street to the north, Beeline Highway to the east, Aero Drive to the south and McLane Road to the west.

Continuing tests indicate that the town's water supply hasn't been affected by the dry-cleaning solvent and that the solvent is not moving past its boundaries, Clendenning said.

The culprit for the MTBE contamination is still unknown, but Nesky said he thinks it was caused by a gasoline station.

"It could be any number of gas stations north of Nugget Street or along the Beeline Highway," he said. He said the Underground Storage Tank division of ADEQ is actively investigating the source of contamination.

Lightning knocks second water treatment plant off-line

Lightning strikes in recent weeks have interrupted production at Payson's expanded water treatment plant, which produces 200 gallons of treated drinking water a minute.

Three different lightning strikes fried controls for the expanded water treatment system, said Michael Nesky, project manager for ADEQ.

"Lightning rods become affordable after three strikes," he said.

The National Weather Service reported as many as 3,000 strikes in the Green Valley Park area at the height of the storm season, Nesky said.

The plant should be up and running again by the end of next week, said Buzz Walker, public works director for the Town of Payson.

The town may buy better surge protection equipment to protect the plant from lightning strikes, Nesky said.

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