Best of 2005 Awards

Griffiss Landfills

Award of Merit: Environmental

A $21.5 million project to cap landfills at the former Griffiss U.S. Air Force Base in Rome, N.Y., has sealed off tons of military hazardous waste.

Awarded by the U.S. Army Corps of Engineers as part of the federal base closure program, the project to cover landfills over 66 acres began in 2002 and will be substantially complete this year.

The Best of 2005 jury was most impressed by the project team's commitment to use local contractors and workers. New Jersey-based Conti Environment & Infrastructure started with in-house staff but transitioned rapidly to a regional workforce, said Rich Hamlin, site superintendent and project manager.

By the second half of the project, the technical staff, craft workers, and management were about 90 percent local, exceeding the federal Base Realignment and Closure Commission's 70 percent standard.

"Unemployment is very high in that area," one juror said. "They used displaced workers. That's an achievement."

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"Given the kind of work they're doing - they're wearing hazmat suits - it's fairly significant [that they found local expertise]," another juror added.

Landfill 1 was the most complex to cap, requiring a groundwater leachate system. Landfill 2-3 had an asbestos disposal cell, Landfill 5 was a heavily wooded four-acre site, and Landfill 7 spread across 11 acres.

The 22-acre Landfill 1 was the largest sector and entailed the most extensive design, engineering, and remediation work. Crews cleared all vegetation from the partially wooded site, then made earthwork cuts and fills to the meet the state-mandated slope range of 2 to 33 percent.

The cap consists of several layers to control movement of moisture and gas. The first is a geocomposite gas venting layer made of plastic mesh, which helps to control and direct methane and other emissions from the landfill. The system moves those emissions toward a series of PVC pipes sunk 7 ft. into the ground, surrounded by stone and extending upward through higher layers and finally curving in a "candy cane" shape above ground.

The next layer is a 40-mg plastic barrier membrane that prevents moisture or gas from reaching the surface. Above that layer is a geocomposite plastic mesh that controls the speed of surface stormwater flowing over the barrier membrane. Gas monitoring probes line the perimeter.

The cap is finished off by another 12 in. of soil, 6 in. of topsoil, and landscaping. A 1,350-lin.-ft., 18- to 22-ft.-deep leachate trench and a 2,400-sq.-ft. leachate treatment system collects and removes contaminated groundwater.

Hamlin said the least routine part of the job was wetlands restoration, in which crews collected and consolidated landfill debris on an acre of the wetlands, reconstructed the natural topography with heavily loaded peat, spread a special grass seed mix, and planted native vegetation.

Key Players

Developer: U.S. Army Corps of Engineers

General Contractor: Conti Environment and Infrastructure

Design Engineer: EA Engineering

Geosynthetic Installation: Chenango Contracting

Surveying: LaFave, White, & McGivern

Common Fill-Barrier Protection-Topsoil: Harvey Construction

Seed-Mulch: Miller's Landscaping