Environmental Services

Arrowhead, as part of the Kemron-Arrowhead Joint Venture was awarded a 5-year, $30M+ contract for the remediation and restoration of numerous abandoned lead mining sites throughout Newton County, MO. The work is being completed as a task order under the EPA Remediation Environmental Services CLIN 2 ID/IQ contract. The work is being administered by EPA Region VII. Work performed under this task order includes providing all labor, equipment, and materials to excavate and transport contaminated mining wastes and soil to a central repository.  

The mining waste is comprised of differing sizes of rock and chat, to fine sand and silt material. The contamination has washed down through the layers of waste and exists in the upper levels of the underlying soils. The Site limit of disturbance is approximately 350 acres and approximately 1,400,000 cubic yards of rock, chat, and soil is to be transported and disposed at a government-provided repository.  Arrowhead is also responsible for the plugging of mine shafts and vent pipes, as well as filling various subsidence pits that are encountered during excavation and/or reclamation activities. All work is performed in accordance with an EPA-approved Mine Shaft Abandonment Plan. 

Site reclamation activities begin immediately following the excavation and removal of all contaminated soils and plugging of all mine shafts, vent pipes, and subsidence pits. Following the removal of contaminated soil and mine waste, Arrowhead regrades and recontours each excavation site to match the natural drainage contours of the area. When necessary, common is transported from a central staging repository to the property and placed and compacted within 6 inches of the desired grade. If required, top soil and amendments will be placed, and final preparation of the yard completed, to accept seeding and any final landscaping features.  

Arrowhead was awarded the Former Atlas “E” Site 11 Missile Site Groundwater Remediation project as a competitive firm fixed-price task order under an ID/IQ ERS MATOC with USACE Omaha District. The project required engineering and construction of a groundwater remedial action at a former Atlas “E” nuclear missile silo located in northeastern Colorado. VOC contamination resulting from past practices of rinsing the missile fuel tank with TCE, following training exercises, resulted in contamination of the surficial aquifer.  Arrowhead’s scope included a wide variety of tasks, from completion of a bench and pilot scale pilot study, preparation of the Decision Document, and implementation of the full-scale In-Situ Chemical Oxidation (ISCO) remedy. 

Arrowhead’s approach to the remediation was based on an ISCO system that employed injection of oxidant and extraction of groundwater to induce a hydraulic gradient. The approach required all groundwater wells to be constructed for use as injection or extraction wells with centralized chemical batch equipment. The flexibility of this system minimized the number of wells required for treatment and allowed treatment to specific areas of the plume, as such, wide scale over-application of oxidant was not necessary to affect treatment, resulting in reduced chemical usage. 

Arrowhead was also responsible for verifying the site conceptual model prior to full-scale construction, including confirming the nature and extent of VOC contamination. This included site-wide aquifer characteristics and potentiometric surface maps. During completion of this work, we also developed a bedrock topography map which proved instrumental in guiding selection of drilling locations, identification of the preferred groundwater movement pathways, and separation of surficial aquifer units into discrete bodies. 

All infrastructure required for ISCO treatment system was been installed by Arrowhead. In total, 120 groundwater wells were installed, and three centralized chemical batching and pumping equipment structures were constructed.  

Arrowhead was awarded a firm fixed price contract to implement a residential removal action at the USS Lead Superfund site located in East Chicago, IN. The site includes part of the former USS Lead industrial facility along with nearby commercial, municipal, and residential areas. Listed on the National Priorities List in 2009, the site’s primary contaminants of concern were lead and arsenic, and the remediation of site contamination was one of EPA Region 5’s highest priorities. Through a competitive procurement, Arrowhead was selected by the EPA Remedial Action Contractor, CH2M, to perform the project. The site was divided into three zones: a residential neighborhood located between the Elgin, Joliet & Eastern Railway Line on the west, Parrish Avenue on the east, East 149th Place to the south, and East Chicago Avenue to the north were designated as Zone 3. EPA Region 5 had committed to the community a cleanup of 120 properties in Zone 3. Approximately 12,000 cubic yards of soil required removal and off-site disposal from the various properties. Each of the properties was also restored to better-than-original condition following remediation. Arrowhead worked closely with local property owners and coordinated a daily workforce of over 45 employees and specialty subcontractors.  

Under contract with a large midwestern utility company, Arrowhead was awarded a fixed price contract to provide demolition, remediation, and restoration services for a large multi-building service center located in central Iowa. In addition to the demolition of above-grade buildings and features, the SOW also required removal/remediation of subsurface soils and infrastructure associated with a former Manufactured Gas Plant (MGP) as well as underground storage tanks. 

The Site consisted of approximately 11.35 acres of land with four primary structures. The structures were one- and two-story buildings that were slab-on-grade construction with masonry/brick walls and metal framing. The primary buildings consisted of the Fleet Garage and Training Building (11,505 square feet), the North Gas Garage (19,000 square feet), the Gas Service Building (47,814 square feet), and the Electric Service Building (87,568 square feet). Asbestos abatement was completed prior to the demolition of the buildings. Three of the buildings contained Vermiculite insulation inside the cavities of the CMU block walls, which separated office space from warehouse/garage areas. 

Coal tar impacted soil below the building footprint(s) on the western half of the property and was excavated to two feet below existing grade. The material was directly loaded into trucks and hauled to a special waste landfill for disposal.  

Various MGP structures containing an additional ranging from 100 to over 3,000 cubic yards of coal tar sludges and soils were also excavated. The eastern half of the property only required deep excavation in designated “hot spot” areas and did not receive any widespread excavation. The total impacted soil and sludge shipped to the landfill for the entire project was 34,843 tons.  

During this process, over 65,000 gallons of groundwater and rain water that pooled in the structures was collected and pumped into a water treatment system. The onsite treatment system consisted of an oil-water separator, 10-micron bag filters, and two 1-ton granular activated carbon tanks. The groundwater was discharged to the public owned treatment works under a groundwater discharge permit obtained from the local wastewater reclamation authority. 

Restoration of the western half consisted of over 21,800 cubic yards of clean backfill and over 7,400 cubic yards of topsoil to provide a 2-foot cover layer over any possible remaining impacted soil. 

An ambient air monitoring program was maintained throughout the Project. The air monitoring program ensured dust, odor, or other air quality concerns were promptly addressed through dust control, work measures, or other mitigation.