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. Preliminary investigation confirmed the presence of chlorinated volatile organic compounds (VOCs).

Working with the 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 operating permitting was 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% on-line efficiency and no violations, reducing the elevated soil gas and groundwater levels more than an order of magnitude.