ROBERT A. EVANGELISTA

STEAM/HOT AIR INJECTION with ACTIVE SOIL MIXING to RECOVER and CONCENTRATE ORGANIC CONTAMINANTS from SOIL into LIQUID FUEL

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GATX Annex Terminal site was located within the Port of Los Angeles in San Pedro, CA. In the 1970s, a massive explosion and fire at the terminal destroyed many of the tanks caused volatile and semi-volatile organic compounds (VOCs and SVOCs) to enter the soil. The purpose of this project was to remove these contaminants that were present in soil at parts per million concentrations and recover them as a liquid fuel for recycling at a cement kiln.

 

Steam/Hot Air Injection with Active Soil Mixing

Steam/hot air injection with active soil mixing technology employed the simultaneous injection of steam, which heated the polluted soil and volatilized (evaporated) the soil-bound VOCs and SVOCs, and the injection of hot air, which pushed the resulting vapors to the surface. A blade auger injected the separate steam and hot air streams into the soil and concurrently mixed the soil in place (in situ). Overlapping blocks of treated soil were “steam cleaned.” The control room monitored the removal of soil contaminants and the auger’s mixing and injection in real time. The toxic chemical vapors released from the soil were transported to and captured at the surface by a vacuum within a rectangular recovery cowling.

The cowling transported the chemical vapors, steam, and hot air to an attached mobile treatment process that removed soil particulates and sequentially cooled the chemical vapors and steam until they condensed into separate liquids. The steam condensate (liquid water) and air were cleaned by separate activated carbon systems and were reheated and reinjected into the soil.

Any blocks of treated soil that did not meet the individual requirements for one or more of the forty nine chemicals of concern were simply resteamed. The results showed that this technology could meet treatment standards set by the State of California and produce a liquid fuel.

Advantages

The advantages of this technology were:

• the minimization of dense non aqueous phase liquid, or DNAPL, pockets remaining in treated soil due to active soil mixing
• the avoidance of harmful volatile chemicals that can escape into the air during soil treatment
• the reuse of the air and the steam’s water
• the recovery of contaminants as a liquid fuel

 

More Information

R. Evangelista, Draft Report of the Pretreatment Soil Sampling and Analyses, the Evaluation of the Extent of the Chemicals of Concern in Pretreatment Soil, and the Proposed Areas (Blocks) that do not Require Remediation for the GATX Annex Terminal, San Pedro, CA. Prepared for GATX Terminals Corporation, 1992. PDF 5.2 MB

Please note, additional reports were written by outside consultants for this project and may be available from the California Department of Toxic Substances Control, Region 4, Site Mitigation Branch.

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