Regulatory Agency: California Environmental Protection Agency, Department of Toxic Substances Control (DTSC), South Coast Air Quality Monitoring District State of California Registered Geologist
Contaminants: Chlorinated Volatile Organics, Organic Compounds
Remediation: Soil Gas (Vapor) and Groundwater
Treatment: Offsite Dual-Phase Extraction and Granular Activated Carbon (GAC) Filtration
Scope: Investigate & RemediateProject Summary

  • Investigative activities at the Site identified contaminants in soil gas and ground water, requiring remediation.
  • ESI conducted site investigation, remedial design and remedial action under DTSC approved workplan to achieve compliance status.
  • Soil gas remediation consisted of extraction and GAC filtration.
  • Dual Phase extraction capability successfully mitigated vapor intrusion concern.

Project Details

Soil and groundwater concerns at the Sheraton Universal Hotel in Universal City, California resulted from former dry cleaning operations located in the basement laundry area.

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The preliminary investigation confirmed the presence of chlorinated volatile organic compounds (VOCs). Working with the California Department of Toxic Substances Control (DTSC) and the South Coast Air Quality Monitoring District (SCAQMD), ESI developed and implemented the remedial site investigation with emphasis on both groundwater and the potential for vapor intrusion impact to indoor air quality.

Based on the steeply sloping site conditions the foundation architecture of the hotel is formidable. This combined with the dynamic geology of the San Gabriel Mountains provided a challenging opportunity for specialized remedial solutions.

After successful Pilot treatment program trials, the Remedial Action Workplan and the operating permit were approved. ESI designed and installed a customized Dual-Phase extraction and filtration system in the sub-basement to depressurize the foundation slab and prevent soil gas build-up and intrusion of vapor into the working area.

The system has operated with 99% online efficiency and no violations, reducing the elevated soil gas and groundwater levels more than an order of magnitude.