Projects Investigating and Remediating Petroleum Contamination of Surficial (Overburden) and Bedrock Groundwater

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Site: Former Bulk Oil Aboveground Storage Tank Facility, Belfast, Maine

ERI designed and supervised a hand-driven temporary micro-well network across a former bulk oil storage AST area. We also designed and directed a second phase of investigation by installing permanent Geoprobe micro-wells that delineated the full extents of the free-phase petroleum release. We performed well gauging, directed test pits, and designed a 600-linear foot oil recovery trench remedial system. The ERI installed remedial system consists of four oil recovery trenches/wells, two total fluid pumps, an oil/water separator and three aqueous phase granular activated carbon (GAC) filters. ERI staff currently performs monthly operation and maintenance and monitoring. The system has been in operation for about 18 months and has recovered approximately 170 gallons of weathered fuel oil.

Site: Former Bulk Oil Underground Storage Tank Facility, Lisbon Falls, Maine

ERI staff co-designed, installed and provided operation and maintenance for a vapor extraction enhanced groundwater pump and treat and oil recovery system at the site. The system controlled the groundwater contaminant plume and oil recovery through groundwater depression and product recovery pumps. The vapor extraction system enhanced remediation while controlling vapor migration. After recovering approximately 250 gallons of oil in 2.5 years the site is on an annual groundwater monitoring/sampling program for closure assessment.


Company experience investigating and remediating petroleum contamination of bedrock groundwater.

Site: Convenience Store, Chelsea, Maine

MTBE was discovered in the store's on-site bedrock water supply and in one other off-site private bedrock well. A UST tightness test revealed one of two USTs was leaking. ERI conducted a hydrogeological investigation of the soils on the store property and sampled area private drinking water supply wells. We directed a subcontractor to advance soil borings to delineate the extents of the soil contamination, determine depth to bedrock and soil types and estimate a volume of soil for future remediation. In addition, ERI supervised UST removals and approximately 300 tons of contaminated soil from the site.

In 1998 ERI performed a bedrock characterization investigation and sited three new replacement water supply wells. We supervised geophysical surveys of old wells, the driller, electrician, plumber and water treatment vendors. In addition, we performed fracture trace analysis, water sampling, pump testing, construction of water treatment sheds and trouble-shot system start-up problems and assisted the residences and new store owners with Chapter 691 issues and long-term water system subsidy programs.

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