Performance Evaluation of a Pilot-Scale Permeable Reactive Barrier at Former Naval Air Station Moffett Field, Mountain View, California. Volume 1

This is a NAVAL FACILITIES ENGINEERING SERVICE CENTER PORT HUENEME CA report procured by the Pentagon and made available for public release. It has been reproduced in the best form available to the Pentagon. It is not spiral-bound, but rather assembled with Velobinding in a soft, white linen cover. The Storming Media report number is A954663. The abstract provided by the Pentagon follows: A pilot scale permeable reactive barrier (PRB) or treatment wall demonstration project was initiated by the U.S. Navy EFA West at the former Naval Air Station Moffett Field site in Mountain View, California about 3 years ago. Performance evaluations and cost-benefit analyses were performed by the U. S. Naval Facilities Engineering Service Center (NFESC) and were sponsored by the Department of Defense (DoD) Environmental Security Technology Certification Program (ESTCP). The Moffett Field PRB uses a funnel-and-gate design, where the funnel is made of interlocking steel sheet piles and the gate consists of a reactive cell filled with zero-valent granular iron. Since its construction in April 1996, groundwater monitoring was conducted on a quarterly basis to demonstrate the effectiveness of the barrier technology in capturing and remediating groundwater that contained dissolved chlorinated hydrocarbon compounds. The primary contaminants of concern at Moffett Field in the vicinity of the PRB are trichloroethene (TCE), cis-1,2 dichloroethene (cDCE), and perchloroethene (PCE) at upgradient concentrations of about 2900 micrograms per liter (micrograms/L), 280 micrograms/L, and 26 microgram/L, respectively. Quarterly monitoring events included water level measurements, field parameter testing, and groundwater sampling at about 75 monitoring points. Two tracer tests using bromide solutions and flow meter testing were also completed in April and August 1997 at the site. Iron cell coring samples were collected and analyzed in December 1997 for use as indicators of reactivity and longevity.