- Company: Charter Contracting Company, LLC
- Industry: Water/Wastewater
- Location: Tewksbury, Massachusetts
- Expected Completion Date: December 21, 2015
- Project Website
Along a winding, tree-lined road in Tewksbury, MA, the Sutton Brook Disposal Area Superfund Site emerges as an astonishingly vast 53 acre multi-lobe landfill with surrounding wetland areas and a rushing brook running through the middle of the site. This former landfill received municipal and industrial wastes from 1957 to 1988 and was never properly closed, impacting the nearby wetlands, surface water, groundwater, sediments, and soils. Charter was selected to perform landfill excavation, consolidation, and capping; anchor trench construction; contaminated soil and buried drum removal; water diversion and treatment; vertical barrier wall installation; groundwater extraction; and wetlands restoration. The final capping and closure of this expansive Superfund Site protects human health and the environment from exposure to industrial contamination and impacted water.
What impact does this project have on America?
When the Sutton Brook Disposal Area was operating, there were documented occurrences of landfill burning, uncovered waste areas, filling of on-site wetlands, waste disposal below the water table, and landfill slopes that exceeded operation plans. During a MassDEP inspection, underground burning was observed through fissures in the ground in the southern landfill lobe. Subsequent investigations revealed demolition debris and soil stockpiles that were encroaching on wetland areas. The presence of improperly managed industrial waste required remedial action to properly excavate, cap, and close the landfill lobes and restore the surrounding wetlands and waterways to protect human health and the environment. The project involved a series of challenging and impactful tasks to complete site remediation, improve surface water drainage, clean-up waterways, and preserve an essential wetland habitat including the following:
• 53 Acres of Clearing, Grubbing, and Grading
• 107,000 Gallons of Contaminated Water analyzed, treated, and discharged
• 89,317 SF of Stormwater Basins and 800 LF of Gravity Sewer Installed
• 16,625 LF of stormwater control benches and 1200 LF of stormwater downchutes
• 57,770 SF of Soil Bentonite Slurry Wall Installed to 48ft to Isolate Groundwater
• 170,000 Tons of Gas Venting/ Protective Cover Sand
• 50 Enhanced and Passive Gas Vents Installed
• 1,760,000 SF of Multi-Layer Cap Installed: GCL, 40-mil HDPE and Geocomposite
• 39,415 CY of contaminated materials consolidated into landfill from drum disposal area
• 132,000 SF of Wetlands Construction and Restoration
• 15,558 On-Road Truck Loads Delivered to the Site
• 6,822 LF of Anchor Trench, up to 16’
• 1 bridge crossing consisting of 146’ of precast concrete culvert
• 230,000 CY of material reshaped on two landfill lobes
• 0 OSHA Recordable Incident Ratev
What interesting obstacles or unusual circumstances did you overcome to complete the project?
The project required installation of 170,000 tons of protective cover sand and more than 1,800,000 SF of geosynthetic clay liner, 40-mil HDPE and geocomposite across 53 acres covering 2 landfill lobes. Due to the significant amount of sloped surfaces impacted by surface water run-off, Charter experienced schedule set-backs following major storm events. Charter overcame this obstacle by installing a series of drainage benches and downchutes that directed stormwater run-off through designated flow areas into a lined anchor trench and surrounding wetland areas. Water bars were also installed to control and manage water entering the site. By managing water flow during storm events, Charter maintained the project schedule and protected cap layers from erosion prior to establishment of vegetation.
To contain groundwater and prevent contaminant migration into Sutton Brook, Charter installed a Soil Bentonite Slurry Wall to 48ft below the ground surface. At a length of 1,700 LF, the subsurface wall posed significant challenges including the removal of obstructions, proper mixing of slurry components, excavating a trench to 48ft, and working along the banks of a flowing brook. Charter used specialized long-reach equipment and support from a key team member to redesign the slurry wall components and install each feature to effectively isolate contamination and protect future impacts.
What dangers and risks did you encounter, and describe any extraordinary methods used to keep workers safe?
Charter implemented the site Health and Safety Program for 45 full-time laborers, operators, and truck drivers and multiple vendors responsible for delivering up to 150 truckloads per day. With more than 15,500 total deliveries to the site and miles of haul roads, traffic management was a constant focus for the project team and safety staff. Visual reminders, frequent communication, and clearly defined traffic plans were all used to create a zero accident environment. Charter excavated multiple former burial and dumping areas, encountering unknown materials and unforeseen conditions. In addition to finding buried drums, Charter uncovered and removed pieces of construction equipment and buried tires. Personal protective equipment was utilized for site activities and upgraded when indicated by monitoring results.
Our designated site Health and Safety Officers performed work zone and personnel air monitoring, managed orientation for new workers, recorded worker certification and training documents, coordinated medical monitoring, conducted daily safety meetings, prepared job hazard analysis, supervised confined space entry, and exercised final authority as needed when planning and executing work tasks to enforce safety regulations. Making safety the responsibility of every person on-site, Charter completed more than 41,000 work hours and closed out the project with zero lost time incidents.
How did you leverage new technologies to work faster and reduce waste?
The project called for installation of a water line from the groundwater extraction system to the municipal sewer. To save time on the project schedule and avoid disturbing the sensitive wetlands area, Charter performed horizontal directional drilling beneath the wetlands. As a result of applying this new technology, Charter completed installation of the groundwater extraction system, extraction well forcemain, and gravity sewer line without impact to the schedule or wetland habitat.
The Sutton Brook project team diligently worked together to develop a combined earth support and geosynthetics installation system. The system allowed for two different rolled geosynthetic materials to be installed vertically in a trench, to a depth of up to 12 feet below ground surface. Through team participation and collaboration to modify the original idea, the final design was implemented to more safely and efficiently install this unusually complex trench system.
To achieve exact grades at this 53 acre site, Charter utilized a Leica GPS base station to control three automated GPS equipped bulldozers and one GPS equipped excavator. Project engineers and surveyors used two GPS rover units and a GPS robotic total station to confirm limits of contaminated areas and collect as-built data. Using these combined GPS devices and experience project team members, Charter precisely controlled grades, minimized over-excavation and re-work, and efficiently completed work areas with real-time data confirmation.