This process should be of particular interest to the city, which must approve development above a toxic groundwater plume that is a mile-and-a-half long and 2,000 feet wide in the Superfund Study Area bounded by Middlefield Road, Ellis Street, and N. Whisman Road. In prior years, the three companies and the U.S. Navy have filtered the ground water with systems called "pump and treat" to clean up the toxic chemicals under the Superfund site that continues to challenge clean-up agencies.
But this method is losing effectiveness and is not expected to reduce the size of the plume in the next 10 years, according to Penny Ready, project manager for the Environmental Protection Agency, who spoke to the Moffett Field Restoration Advisory Board in May. She said the EPA is studying a new process, in which microbes injected into the ground turn TCE into organic ethane and ethane gases, neither of which damage the ozone layer.
A similar cleanup method has recently proven itself to be effective in the rapid cleanup of test areas at Moffett Field, including a 2,500-square-foot area northwest of Hangar Three. Injecting 23,000 pounds ($57,000 worth) of a product called EHC to break down the TCE, the Hangar Three site was cleaned up to well within drinking water standards in only two years, according to a report given by Navy officials at this month's meeting of the Moffett Field Restoration Advisory Board.
This is a technique that City Council members should support by requiring all new developments over TCE contaminated sites to first clear away as much of the toxic plume as possible with the new technology. It makes much more sense to treat the soil before covering a site with buildings or pavement that would block something like EHC from being placed in the ground.
This week the City Council approved a large office project over one of the most concentrated sections of the toxic plume, and apparently missed an opportunity to push for cleanup of the site with the new technologies. The 29.3-acre property is bounded by N. Whisman Road to the west, Ellis Street to the east and is within 2,000 feet of the Middlefield Road light rail station.
The developers of this property received a Transit-Oriented Development permit to add 181,000 square feet and two parking structures to the project, as well as permission to take down 354 of the 823 trees on the property, including 22 classified as heritage trees. In return for granting these requests, the City Council had a golden opportunity to require the developer work with polluters and the EPA to, at the very least, examine the possibility of using the latest technology to clear away much of the toxic plume underneath the project site.
The cost of such an effort is borne by the polluters, not the developer, so there is little reason for developers not to support it. And for polluters, it could be well worth the investment if it could end their payouts for expensive, long-term treatment.
City officials say it's the role of the EPA to make toxic cleanup requirements. But we suggest the city study this technology and partner with the EPA to promote it so building tenants will not have to face the prospect of working on top of a toxic plume of carcinogenic TCE.