STC REMEDIATION, A DIVISION OF
OMEGA ENVIRONMENTAL, INC.

(formerly SILICATE TECHNOLOGY CORPORATION)
(Organic Stabilization and Chemical Fixation/Solidification)

TECHNOLOGY DESCRIPTION:

STC Remediation, a division of Omega Environmental, Inc. (STC Remediation), has developed both chemical organic stabilization and chemical fixation/solidification technologies that treat inorganic and organic solid hazardous wastes (see photograph below). Leachable organic contaminant concentrations are reduced to well below regulatory limits. The chemical fixation/solidification technology forms insoluble chemical compounds, reducing leachable inorganic contaminant concentrations in soils and sludges.

Treatment of Contaminated Soil

STC Remediation's technology has been successfully implemented on numerous full-scale hazardous waste remediation projects involving up to 100,000 cubic yards of waste per project.

These sites include Superfund sites and industrial sites across the United States and in Italy.

STC Remediation has evaluated various materials handling and mixing systems for use on full-scale remediation projects. Materials handling processes consist of pretreatment processes for screening and crushing contaminated soils, and placement and conveying systems for handling treated material. Mixing systems consist of various batching plants, pug mills, and high-shear batch mixing systems to properly meter and mix reagents with contaminated soils. STC Remediation provides full on-site technical support to ensure effective application of the treatment technologies, documentation, and quality assurance/quality control procedures during the treatment process.

WASTE APPLICABILITY:

STC Remediation's technology can treat a wide variety of hazardous soils, sludges, and wastewaters, including the following:

• Soils and sludges contaminated with inorganics, including most metals, cyanides, fluorides, arsenates, chromates, and selenium
• Soils and sludges contaminated with organics, including halogenated aromatics, polynuclear aromatic hydrocarbons, and aliphatic compounds
• Wastewaters contaminated with heavy metals and emulsified and dissolved organic compounds, excluding low-molecular-weight organic contaminants such as alcohols, ketones, and glycols

STATUS:

This technology was accepted into the SITE Demonstration Program in 1988. STC Remediation's demonstration project was completed in November 1990 at the Selma Pressure Treating (SPT) Superfund site in Selma, California. STC Remediation was subsequently selected for the full-scale remediation of the SPT site, which is contaminated with organics, mainly pentachlorophenol (PCP), and inorganics, mainly arsenic, chromium, and copper. The SPT site was remediated in 1993 using STC Remediation's treatment process. The Applications Analysis Report (EPA/540/AR-92/010) is available through the National Technology Information Service (Order No. PB93-172948). The Technology Evaluation Report (EPA/540/R-92/010) and Demonstration Bulletin (EPA/540/MR-92/010) are available from EPA.

DEMONSTRATION RESULTS:

The SITE demonstration yielded the following results:

• The organic stabilization technology reduced total extractable PCP concentrations up to 97 percent. The chemical fixation/stabilization technology stabilized the residual PCP concentrations to very low leachable levels (from 5 to less than 0.3 milligrams per liter).
• STC Remediation's technology immobilized arsenic and copper, while chromium remained well within regulatory limits.
• Long-term monitoring at 18 and 32 months following the demonstration project provided comparable results for PCP, arsenic, and copper, while chromium remained well within regulatory limits.
• The treated wastes had moderately high unconfined compressive strength, averaging 300 pounds per square inch (psi) after 28 days, increasing to more than 700 psi after 18 months.
• Permeability of the treated waste was low (less than 1.7 x 10^-7 centimeters per second). The relative cumulative weight loss after 12 wet/dry and 12 freeze/thaw cycles was negligible (less than 1 percent).
• Treatment costs depend on specific waste characteristics.

FOR FURTHER INFORMATION:

EPA PROJECT MANAGER:
Edward Bates
U.S. EPA
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7774
Fax: 513-569-7676

TECHNOLOGY DEVELOPER CONTACTS:
Scott Larsen or Stephen Pegler
STC Remediation
7650 East Redfield Road, Suite D-5
Scottsdale, AZ 85260
602-948-7100
Fax: 602-991-3173