Remediation of Fractured Bedrock Containing Light Non-Aqueous Phase Liquid (LNAPL)
Monday, September 23, 2013: 3:05 p.m.
Sean R. Carter, PE
,
Matrix Environmental Technologies, Orchard Park, NY
Craig Zink, PG, CPG
,
Matrix Environmental Technologies, Orchard Park, NY
Robert Gill, CPG
,
Matrix Environmental Technologies, Orchard Park, NY
Kinyorda Sliwiak
,
Sunoco, Inc (R&M), Syracuse, NY
Light non-aqueous phase liquid (LNAPL) and elevated volatile organic compounds (VOCs) were detected in groundwater at an active gasoline station in Niagara Falls, New York. The station was closed and the USTs, fuel lines, and one set of fuel dispensers were removed. Surficial geology consists of 5 to 9 feet of fill material or native clay overlying highly fractured, gray to light gray limestone. Groundwater is present in bedrock at approximately 11 feet bgs and flows in a fracture-oriented southeasterly direction. Monitoring wells contained LNAPL up to 2.5 feet in thickness and groundwater BTEX concentrations as high as 82 milligrams per liter (mg/L). A Remedial Action Plan was developed to remove LNAPL and reduce groundwater VOCs using multiple technologies in a phased approach.
Submersible top-loading pneumatic pumps were installed in multiple wells. LNAPL and groundwater was pumped to an on-site treatment system and discharged to a sanitary sewer. The system operated for 47 months, treated nearly 500,000 gallons of groundwater, and reduced site-wide LNAPL thickness to less than 0.10-feet.
The remediation system was then augmented to include vacuum-enhanced groundwater pumping to increase well yield, improve hydraulic control, and extract subsurface vapor-phase VOCs. Financial restrictions associated with permitting necessitated the premature deactivation of the pump and treat portion of the system after 18 months of operation. The system extracted 473 pounds of VOCs, and was successful in removing any remaining LNAPL and reducing groundwater BTEX concentrations to below 0.5 mg/L.
To complete remediation, the injection of oxygen gas into 2 injection wells screened in bedrock fractures was tested in mid-2012, with eventual full scale implementation into 15 injection wells. Groundwater dissolved oxygen has increased to the target level of 5 mg/L and the system will be operated for an estimated 18 months.
Sean R. Carter, PE, Matrix Environmental Technologies, Orchard Park, NY
Mr. Carter is the President of Matrix Environmental Technologies and is an Environmental Engineer with 20 years experience in remediation, water, air and waste treatment processes. He has designed, field-tested and operated biological, chemical and physical treatment systems for a wide range of waste streams. He was the design engineer for the Matrix Oxygen Injection System and Matrix Biofilter. Mr. Carter takes on challenging remediation projects that require creative solutions to meet client and regulatory goals. He also works on projects with shared risks and guaranteed or performance based contracts.
Craig Zink, PG, CPG, Matrix Environmental Technologies, Orchard Park, NY
Mr. Zink is a Professional Geologist and Project Manager with 24 years experience in subsurface investigation and remediation of retail and bulk storage petroleum facilities, commercial and residential properties, railways and landfills. His experience includes subsurface investigations and site characterization, response to petroleum-related emergencies, data analysis, report and proposal preparations, remedial system design, management of remedial system installation, operation and maintenance, and negotiations with regulators.
Robert Gill, CPG, Matrix Environmental Technologies, Orchard Park, NY
Mr. Gill has 12 years of professional experience working with Matrix Environmental Technologies. He provides specialized skills related to his field including knowledge in environmental geochemistry, environmental mineralogy, and quantitative hydrogeology. As a manager of numerous projects, each requiring specific needs and attention, Mr. Gill has the ability to coordinate multiple tasks. Mr. Gill is also experienced in developing remediation work plans/proposals, UST closure assessments, supervising the design, installation, and operation and maintenance of remedial systems, and preparation of technical reports.
Kinyorda Sliwiak, Sunoco, Inc (R&M), Syracuse, NY
Kinyorda has worked in the petroleum remediation industry for more than 12 years. Kinyorda graduated from The Pennsylvania State University with a B.S. in Geo-Environmental Engineering in 1998. Kinyorda began her career with Groundwater & Environmental Services, Inc. where she managed the Sunoco remediation portfolio. For the past 8 years, Kinyorda has been an environmental engineer for Sunoco. At Sunoco, she directly manages 100 remediation projects in Pennsylvania and New York and is the senior technical adviser for 100 projects across Sunoco's retail market.
