Lessard Environmental Incorporated: Case Study #2

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Remedial Case Study

Overview:

A heating oil spill in the basement of a residence was partially addressed by excavation. However due to the age of the structure and the condition of the foundation, excavation closer to the fieldstone foundation was not an option. LEI was subcontracted by the primary environmental consulting firm to perform Chemox on the remaining soil contamination adjacent to the building foundation. Cleanup goals were met with just 7 injection events spread over 2 months.

Assessment:

Most of the assessment activities were previously handled by the primary consultant that managed the excavation activities. LEI utilized this data to design an appropriate Chemox delivery system to the affected areas via the strategic placement of pvc injection points. In addition the following activities took place prior to initiating active remediation:

Developed health and safety plan
Established baseline conditions by sampling and monitoring groundwater for key parameters including dissolved oxygen, iron and chlorine

Response Activities:

Typical response activities would have continued with excavation, requiring the expense of supporting the building, replacing or repairing the foundation and any other associated damage caused by this crude approach. However, LEI was able to clean up the remaining petroleum constituents for a reasonable cost while avoiding additional costs and risks of further property damage. Under the guidance of LEI modifications were made to the sidewalls of the excavation by the primary consulting firm to optimize the Chemox delivery system. Final closure reporting was completed by the primary consultant with an appendix covering the Chemox treatment program provided by LEI. Treatment program preparation and administration included the following activities:

Installed PVC injection points
Directed primary consultant to modify excavation walls to optimize the injection delivery system
Designed and implemented ventilation system for safety purposes
Monitored air and groundwater for key parameters during injection events
Conducted post injection groundwater sampling to confirm the return to baseline conditions

Key Monitoring Results:

Current Site Status:

Site Closed — No Further Remedial Actions required