Federal Creosote Superfund Site

Significant Project Features

• Excavation, characterization, transportation and disposal of 450,000 cy of contaminated material from 2 lagoons and 100 residential and commercial properties for offsite thermal treatment or landfill disposal
• Work area and perimeter air monitoring system implemented to protect project personnel and community residents during remediation activities
• Design, construction, operation and maintenance of a 450 GPM groundwater treatment and excavation dewatering system
• Design and installation of a soldier pile, steel sheeting, and lagging system to protect an active railroad during deep excavations
• Multi-media sampling and chemical analysis of air, soils, and water

Project Gallery

History & Location Details

Project Description

Key areas of remediation included:

• WASTEWATER TREATMENT
  Sevenson designed, operated, and maintained a temporary groundwater treatment and dewatering system to dewater excavation areas. A series of 80 dewatering wells and dual-containment force mains were installed in and around the lagoon areas. Over 80 M gallons of construction water was extracted and treated using oil/water separation, organo-clay and bag filtration, and liquid phase carbon polishing prior to surface discharge to the Millstone River under a B4B Qualifying Permit.
• EXCAVATION OPERATIONS
  Deep excavation of the lagoon area (up to 34 feet BGS) required the design and installation of soldier pile, steel sheeting and wood lagging system. The lagging system protected the active railroad that bounds the Claremont Development; the sheeting protected non-rail sides of the excavations. Working in Level C or D (modified) PPE and using conventional construction equipment, contaminated soil was excavated and stockpiled according to classification (thermal, Subtitle C, or Subtitle D) prior to loading and offsite transportation. Soils were transported in lined dump trailers to licensed/approved disposal facilities.Primary excavation limits at each property was based on cut lines derived from GeoProbe® characterizations. Secondary excavation was based on confirmatory grid sampling as outlined in Sevenson’s approved SAP. Imported backfill was tested prior to acceptance at the site. As the fill was placed and compacted, Sevenson’s QC conducted Troxler compaction testing to ensure the structural stability of restored areas.
• PERIMETER AIR MONITORING
  Sevenson developed a Perimeter Air Monitoring Program for airborne contaminants. This program included real time monitoring for both particulates and volatile organic compounds and documentation monitoring using EPA methods T0-13, T0-14 and PM-10. A unique feature of the real time monitoring was the use of telemetry to transmit the VOC results to a central command. This enabled Sevenson to implement odor and/or vapor control programs quickly, when required. Due to the close proximity of the residential community, odor control measures (a foaming system was used for extended periods of exposure to odors and a misting system was used in conjunction with foaming during excavation/loadout operations, as necessary) were implemented to control creosote emissions during the excavation work.
• SITE RESTORATION
  Excavation areas were backfilled with compacted common fill to rough grade elevations. Coordination with local utility companies was required to replace buried utility mains, manhole structures and service laterals to each property, as well as overhead utility poles and lines. Concrete structures, (i.e. curb, gutter, sidewalk, driveway, apron, and patio), demolished prior to excavation activities, were replaced. Landscaping, topsoil and sod were installed to meet or exceed preconstruction conditions.
• CHEMICAL QUALITY MANAGEMENT
  Sevenson managed data for 3,600 air, soil, and water samples. Electronic delivery of analytical results were provided by Sevenson’s in-house laboratory. Chemical QC inspections verified that all aspects of the approved SAP were followed and data met project requirements.