Project Merit: Remediation

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TRC Companies Inc. (Lowell, MA) for its remediation design and construction work at a former manufactured gas plant (MGP) and Superfund site in Vermont, located close to a large lake and drinking water supply. The MGP wastes impacted sediments in a lake tributary and were capped in place in 2002. Within four years, low part-per-billion levels of BTEX contaminants were detected in two monitoring wells 80 feet from the lake, and concentrations were increasing considerably. Based upon this data, TRC determined that a vertical barrier was necessary to prevent further contaminant migration. The worksite was a railroad embankment that presented construction challenges since it was less than 100 feet wide, surrounded on both sides by water, and had three active railroad lines, a recreation path, and a 34kV overhead electric transmission line running through the site. After completing field investigations and evaluating options, TRC recommended and designed a partially penetrating, 300-foot-long, 40-foot-deep jet grout barrier wall to block NAPL migration in permeable sands and redirect the dissolved BTEX fraction up and into an overlying peat layer with a high organic carbon content to provide treatment. The unusual "funnel and gate" design accounts for groundwater flow reversals, requires no power, halts the migration of NAPLs, and is sustainable and cost effective.

Cabrera Services Inc. (East Hartford, CT) for its completion of turnkey remediation activities at the Linde Formerly Utilized Site Remedial Action Program (FUSRAP) site in Tonawanda, New York, thereby securing unrestricted release of the 135-acre manufacturing facility. Serving as the prime contractor under a multiple-award remediation contract awarded by the Army Corps of Engineers' Buffalo District, Cabrera managed all aspects of the remediation; including safety, quality, radiological release, restoration, transport, and disposal tasks. Using precision excavation techniques, Cabrera removed 25,440 tons of radiologically contaminated soil in close proximity to buildings, utility lines, and rail spurs. The company also secured state approval for the beneficial reuse of 29,800 tons of soil and crushed concrete as on-site backfill, and for the off-site recycling of 16,857 tons of non-contaminated debris, thereby achieving more than $10 million in cost savings. Cabrera was commended by the Corps of Engineers for achieving a stellar safety record, with zero lost-time incidents in the 231,864 hours worked on the project. Cabrera completed the project more than three years ahead of the task order's period-of-performance end date of September 30, 2017.

O'Brien & Gere (Syracuse, NY) for its design of the remedial program strategy for implementing a combination of in situ remedial technologies at the largest in situ thermal remediation site in the world, the Teterboro Landing site in Teterboro, New Jersey. For 70 years, the 63-acre site was used for manufacturing aircraft technology. In 2007, it was purchased for redevelopment, with an accelerated timeframe of 3.5 years needed to complete the site investigation and cleanup. O'Brien & Gere was contracted as the project's lead environmental consultant, and to provide Licensed Site Remediation Professional (LSRP) oversight services to remediate the site and prepare it for commercial redevelopment. The company successfully managed a variety of innovative investigation and remediation technologies to complete the characterization and remediation of large, multi-acre chlorinated-solvent source zones within the required redevelopment timeframe. A significant component of the remediation involved in-situ thermal treatment, where remedial goals were met through an in situ thermal desorption (ISTD) treatment program. Approximately 35,000 pounds of chlorinated volatile organic compounds (CVOCs) were removed over 3.2 acres with depths extending to 40 feet. The company also identified a secondary area that warranted in-situ chemical oxidation treatment due to the discrete nature of the CVOC impacts.

TerraTherm Inc. (Gardner, MA) for its role in delivering and implementing the ISTD remedial solution at the Teterboro Landing site (see above). TerraTherm's lump-sum, fixed-price contract value was $15.5 million for turnkey service and guaranteed cleanup, covering an area of 3.2 acres with a treated volume of 122,000 cubic yards of contaminated soil. The contamination consisted of chlorinated compounds including tetrachloroethylene, trichloroethylene, vinyl chloride, and Freon-113. The cleanup at the site, which operated for less than eight months and was completed in 2014, constituted the largest ISTD project ever completed. In order to confirm complete treatment and achievement of the regulatory-required remedial goal of 1 milligram per kilogram (mg/kg) of chlorinated solvents or less, more than 270 soil samples were collected from 56 locations. Comparing the pre- and post-treatment soil concentrations, the four principal CVOCs were each reduced by greater than 99.99%.