The way things work The way things work (April 30, 2004)

Public gets a behind-the-scenes look at TCE clean-up systems in MV

By Grace Rauh

Under a bright blue sky, a crowd of curious spectators cross the Nokia parking lot and huddle around a groundwater treatment system on the technology company's property.

The clean-up facility is surrounded by a tall fence and would hardly prompt a second glance from most people, but the group gathered there last Wednesday was aching for a peek and an explanation. This was, after all, the first public behind-the-scenes tour of two new clean-up systems used to remove the cancer-causing solvent TCE from Mountain View's ground water.

"When you see it, it's impressive. The technology is impressive," said Jane Horton, a Northeast Mountain View Advisory Council board member. "And the safeguards that are with it, it was good to see that."

The council tracks the cleanup of TCE-contaminated sites in the northeast region of the city.

To the untrained eye, the clean-up systems at the old Fairchild Semiconductor plant and Raytheon are a jumble of pipes, pumps and tanks. But following two lessons from treatment system experts, tour-goers learned exactly how the TCE is removed in the area bounded by Whisman Road, Middlefield Road, and Ellis Street.

"I'm glad to have the opportunity to find out more about what is going on here," said Mary Williams, who used to live in northeast Mountain View, but moved from the city in 1999.

Although no longer a resident, Williams returns regularly for tai chi classes and follows the TCE clean-up efforts. She and a friend would take walks along Whisman Road and "we just used to wonder, do I want to be walking here? I don't know," she said.

Staying on top of new clean-up systems has helped Williams appease her curiosity and allay old fears about the contamination.

"When I lived there, it was always something to worry about," she said.

The treatment systems employ two different methods to remove TCE. At the Fairchild site, water is pumped into a sediment filter from 10 wells spread throughout the property. Once sediment is removed, the water passes through three vessels that contain 5,000 pounds of carbon each and clean water is then discharged into the storm drain system. Raytheon uses an oxidation process to remove TCE.

Although both systems successfully remove the cancer-causing solvent, the carbon treatment doesn't remove a certain chemical --1,4-dioxane -- that has been found in small amounts near the Raytheon facility. The oxidation process removes both.

The treatment systems were installed in 2003 after a group of residents grew increasingly concerned about the "air strippers" formerly used in the clean-up efforts. The air strippers were designed to emit TCE in amounts below the safe level, but residents called for new treatment systems to entirely remove the chemical.

Environmental Protection Agency officials and experts on the treatment facilities led the tour that drew roughly 20 people, most of whom are active NMAC members. Many live near the clean-up facilities or work for companies that own office space above the contaminated plume.

E-mail Grace Rauh at grauh@mv-voice.com

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