Evaluation of Waste Stabilized by the Soliditech SITE Technology

The Soliditech technology demonstration was conducted at the Imperial Oil Company/Champion Chemicals Superfund Site in Monmouth County, New Jersey. Contamination at this site includes PCBs, lead (with various other metals), and oil and grease. The Soliditech process mixes the waste material with proprietary additives, pozzolanic materials, and water, in a batch mixer. Technical criteria used to evaluate its effectiveness include (1) short-term extraction and engineering tests; (2) long-term extraction and leaching tests; (3) petrographic examination; and (4) structural integrity observations. Three different waste types-contaminated soil, waste filter cake material, and oily sludge-and a sand blank were treated. Fourteen cubic yards of treated waste monoliths, and nearly 300 cast cylindrical mold samples were produced. Neither PCBs nor volatile organic compounds were detected in the TCLP extracts of treated wastes. Significantly reduced amounts of metals were detected in the TCLP, EP, BET, and ANS 16.1 extracts of treated wastes compared to untreated. Low concentrations of phenols and cresols were detected in post-treatment TCLP extracts. The pH of treated waste was near 12. Unconfined compressive strength of treated wastes was high; permeability was very low. Weight loss after wet/dry and freeze/thaw cycles was very low. Portland cement contributed several metals to the treated waste. Physical stability of treated wastes was high. Data from all extraction and leaching tests showed negligible release of contaminants. Phenols and cresols appeared to be formed during the stabilization reactions. Morphologic observations confirmed changes in physical stability of large blocks of treated waste over time.