Electronics Manufacturing Facility Solvent Assessment, Masaryktown, Florida
CES conducted an assessment of solvents released at an electronics manufacturing facility. Solvent contamination occurred over several decades due to the improper disposal of spent products. The contamination was initially discovered in the 300-foot-deep on-site potable supply well, which had to be abandoned. Assessment activities included test borings advanced use direct-push technology and split-spoon samplers; installation of single- and multi-cased monitor wells using mud rotary and sonic drilling methods; and the collection and analysis of soil and groundwater samples. Soil and groundwater plumes were fully delineated and proved that the contamination had not migrated offsite. Monitoring demonstrated that the groundwater plume was stable. A $1 million cleanup was avoided through the use of engineering and institutional controls to achieve site closure.
Municipal Maintenance Facility Hazardous Waste and Petroleum Assessment, Brooksville, Florida
CES conducted an assessment of 5-acre former fleet maintenance facility that featured 31 Areas of Concern (AOC’s), including leaking underground storage tanks (LUSTs), vehicle maintenance garage, pesticides storage and mixing area, leaking asphalt emulsion storage tanks, industrial wastewater discharges, and paint marking equipment storage and maintenance areas. Contaminants of concern were petroleum hydrocarbons, solvents, pesticides, and metals including arsenic, barium, chromium, lead and selenium. Affected media included perched zone and Floridan aquifer groundwater; shallow and deep soil and limestone; and offsite stream sediment. Work included completion of more than 500 soil borings using a combination of direct-push technology, hollow-stem auger/split spoon, sonic coring, and hand auger methods; installation of 89 monitoring wells, including 19 vertical delineation wells; collection and analyses of soil and groundwater samples; aquifer performance tests (APTs), and discrete-interval aquifer packer tests. An interim source removal was completed along site perimeter and in surrounding residential areas to eliminate exposure and the site was closed through the use of engineering and institutional controls.
Filling Station Petroleum Assessment and Remediation, Brooksville, Florida
CES completed an assessment and cleanup of a petroleum release at a country store located within the cone of depression of a large municipal well field. The assessment included soil sampling using direct-push technology and split-spoon samplers and the installation of shallow and deep monitor wells using hollow stem augers, mud rotary and sonic methods. The assessment demonstrated that the petroleum contaminants had breached the confining unit and entered the Floridan aquifer, putting the well field at risk. CES developed and implemented a remedial action plan (RAP) to address soils and perched zone and Floridan aquifer groundwater. This was a difficult remediation project due to the depth to groundwater (58 feet), the heterogeneous subsurface lithology (sands and clays overlying limestone), and migration of the plume beneath a state highway. Work activities included evaluation of remedial alternatives, installation of pilot test wells, air sparge/soil vapor extraction pilot testing, preparation of a remedial action plan recommending air sparging and soil vapor extraction (AS/SVE) augmented with multi-phase extraction (MPS), development of design drawings, solicitation of construction bids, selection of contractors, installation of AS and SVE wells, system installation and construction oversight, and system commissioning and start-up and, at the end of the cleanup, system removal and well abandonment.
Asphalt Plant Oil/Water Separator Assessment and Remediation, Gainesville, Florida
CES provided assessment, remediation, and post-cleanup monitoring services for discharges associated with former truck wash and oil/water separator at an active asphalt plant. Assessment included installation and sampling of 53 shallow soil borings and 14 groundwater monitoring wells. Following approval of site assessment, CES designed a site remediation strategy consisting of soil excavation to remove impacted soils that were acting as a source of hydrocarbons to groundwater, and application of bio-enhancement products to remediate residual hydrocarbons in soil and groundwater. A total of 16,990 gallons of groundwater was recovered by the dewatering system and properly disposed of. Confirmatory side-wall and pit bottom samples showed that all petroleum-impacted soils were successfully removed. Post-excavation groundwater monitoring showed that dissolved hydrocarbon concentrations were all below cleanup target levels.
Limestone Mine Arsenic Assessment and Remediation, Aripeka, Florida
High levels of arsenic were detected in confirmatory samples collected following the excavation of used-oil impacted soil at the maintenance shop used by the mining company. Assessment of the arsenic required the installation of 74 soil borings and 32 monitor wells, including vertical delineation wells, and the collection and analysis of soil, sediment, groundwater and surface water samples. The arsenic plumes were fully delineated in all media and all impacts were determined to be onsite. Based on arsenic distribution and chemical trends, the arsenic was proven to be naturally occurring and associated with a marl layer situated between surficial sands and the deeper limestone. The arsenic was spread across the site as a consequence of the mining activity. CES prepared a remedial action plan that called for placement of impacted soils below pavement planned for county park and boat ramp. A restriction on the use of the groundwater will be used to prevent exposure to the arsenic present in the aquifer.