ENVIRONMENTAL CASE STUDIES

Case Study 1: Major Metropolitan Airport

Project Description:
Jet fuel was released from underground unprotected steel lines which delivered product from bulk storage area to terminal access points. The release impacted underground employee tunnel and passenger elevator sumps. Employees and passengers complained of illness.

Assessment required mapping sub-grade construction structures and buried conduit locations to determine pathway of contaminant migration. Vapor piezometers were installed across the terminal basement, tunnel, and piping route to allow monitoring of migration, and determine location of source.

Once source and migration pathways were located, product and vapor extraction points were placed for recovery of impacted vapors. Extraction of source product was accomplished via recovery vacuum drop tubes. Source area depletion resulted in mitigation of volatile emissions. Continued vapor extraction beneath terminal created negative pressure gradient and resulted in opening area to occupation. System operated for 6 months.

Cost Savings:
Through the use of value engineering, remedial activities were optimized and long term spending reduced. After 6 months of operation, on-going remedial activities included natural attenuation only. Long term costs associated with an active remedial system, and legal defense from employees impacted by health risks were estimated at well over $1,000,000.

Case Study 2:  DNAPL Remediation

Project Description:
Remedial activities in result of a release of chemical used in process of manufacturing lighting equipment in a factory located near Detroit. Storage tank was located beneath factory floor consisting of approximately 24” reinforced concrete. Operation of storage tank continued until plume had migrated to adjacent residential property.

The source area was recovered through the use of enhanced soil vapor extraction directed just above the lower confining layer. Risk assessment models determined that no immediate or long term health risks existed for the neighboring property.

Cost Savings:
Long term remedial expenditures were reduced to annual groundwater sampling program, and community awareness.

Case Study 3: Project Name: Service Station Closures

Project Description:
Environmental program included management of 85 locations statewide. Scope of work included assessment, remediation, closure. Through a three year term, 33 locations had been closed through a negotiated quarterly groundwater sampling analysis program. Contaminant was restricted to petroleum products.

Cost Savings:
Negotiated closure plan provided limited three year expenditure for subject locations.

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