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

Author: Charles Reeter
Publisher:
ISBN: 9781423553304
Category :
Languages : en
Pages : 191

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Book Description
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. Data from the quarterly monitoring, tracer testing, and iron cell coring have been used to determine the overall barrier performance. Since the first sampling event in June 1996, concentrations of all chlorinated compounds were either reduced to non-detect (ND) or to below the drinking water maximum contaminant levels (MCLs) within the first 2-3 feet of the permeable iron cell (gate).