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EPA/540/R-02/501A
SITE Technology Capsule:
Demonstration of Rocky Mountain Remediation Services Soil Amendment Process
(PDF, 57 Kb, 10 pp)
July 2002
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Abstract
RMRS developed the EnvirobondT process to treat heavy metals in soil. This phosphate-based technology consists of a proprietary powder and solution that binds with metals in contaminated waste. RMRS claims that the EnvirobondT process converts metal contaminants from their leachable form to a stable, nonhazardous one.
The EPA SITE Program evaluated a pilot-scale application of the EnvirobondT process at two locations in September 1998. The EnvirobondT process was applied to the soil surface and tilled 6 inches into the lead-contaminated soil.
Personnel used the Toxicity Characteristic Leaching Procedure (TCLP) to analyze treated and untreated soil samples for lead and a method for bioavailable lead to support two primary objectives. Primary objective 1 (P1) evaluated whether EnvirobondT can treat lead-contaminated soil to meet the Resource Conservation and Recovery Act (RCRA)/Hazardous and Solid Waste Amendments (HSWA) alternative universal treatment standards (UTS) for land disposal of lead-contaminated soils. The alternative UTS for soil contaminated with lead is determined from the results of the TCLP. The alternative UTS is met if the concentration of lead in the TCLP extract is no higher than one of these: (1) 7.5 milligrams per liter (mg/L), or (2) 10 percent of the lead concentration in the TCLP extract from the untreated soil. Contaminated soils with TCLP lead concentrations below the alternative UTS meet the RCRA land disposal restrictions (LDR), and are eligible for disposal in a land-based RCRA hazardous waste disposal unit. The alternative UTS is defined further under Title 40 of the Code of Federal Regulations (CFR), Chapter I, part 268.49 (40 CFR 268.49). To meet that objective, soil samples were collected before and after the application of EnvirobondT. The soil samples were analyzed for TCLP lead concentrations to judge whether the technology met objective P1. Analysis of the data showed EnvirobondT reduced the mean TCLP lead concentration at the inactive pottery factory from 382 mg/L to 1.4 mg/L. The treated soil meets the alternative UTS for soil at the inactive pottery factory. Data from the trailer park were not used to evaluate P1 because TCLP lead concentrations in all treated and untreated soil samples from this location were either at or slightly higher than the detection limit of 0.05 mg/L.
In primary objective 2 (P2), staff evaluated whether EnvirobondT decreased soil lead bioaccessibility by 25 percent or more, as defined by the Solubility/Bioaccessibility Research Consortium's (SBRC) Simplified In-Vitro Test Method for Determining Soil Lead and Arsenic Bioaccessibility (simplified in vitro method [SIVM]). EPA Lead Sites Workgroup (LSW) and Technical Review Workgroup for lead (TRW) do not endorse an in-vitro test for finding soil lead bioaccessibility (Interstate Technology and Regulatory Cooperation [ITRC] 1997). To meet objective P2, personnel collected soil samples before and after applying EnvirobondT. They analyzed soil samples for soil lead bioaccessibility to find whether the technology met objective P2. Analyzing data showed that EnvirobondT reduced the soil lead bioaccessibility by about 12.1 percent, which is less than the project goal of at least a 25 percent reduction in soil lead bioaccessibility.
The staff examined 12 cost categories for a plan in which the EnvirobondT process was applied at full scale to treat leadcontaminated soil at a Superfund site. The cost estimate assumed the size of the site was 1 acre, and that the treatment was applied to a depth of 6 inches, which results in an estimated treated volume of about 807 cubic yards. The estimate assumes the site's soil characteristics and lead concentrations were similar to those of the CRPAC evaluation. Based on these assumptions, the total costs would be $33,220, which is $41.16 per cubic yard of soil treated. Costs for applying the EnvirobondT process may vary.
Contact:Edwin Barth
barth..ed@epa.gov}