BTEX Remediation under Challenging Site Conditions Using In-Situ Ozone Injection and Soil Vapor Extraction Technologies: A Case Study

Abstract

Remediation was successfully completed in a petroleum-contaminated site using ozone sparging combined with soil vapor extraction technologies. The site contained high levels of BTEX contamination in dissolved, adsorbed, and free phases. The presence of fine-grained soil, smear zone contamination, and shallow groundwater posed challenging site conditions for this remediation. Active remediation was performed for approximately 18 months followed by one year of post-remediation monitoring. Application of soil vapor extraction technology effectively removed free phase contamination. Biodegradation during active and post-remediation periods also played a role in bringing down the contaminant levels and achieving closure of the release. The cost of this remediation approach was estimated to be $2.04 per cubic foot ($72.08 per cubic meter) and found to be cost-effective. Timely completion of the project prevented the spreading of contaminants towards the down-gradient residential and school properties.

Keywords:

• Contaminant removal
• cost of remediation
• biodegradation
• horizontal SVE
• vertical SVE
• fine-grained soils
• shallow groundwater

Acknowledgement

Funding for this project was provided under Arizona's State Assurance Fund and American Recovery and Reinvestment Act. The remediation approach was implemented through Groundwater and Environmental Services, and post-active remediation activities were performed through Blaes Environmental Management, Inc., State Environmental Contractors contracted with the State of Arizona.