Remediation of Chromium-Contaminated Soils— Pilot-Scale Investigation

Abstract

This paper describes the results from the pilot-scale demonstration study performed to remediate chromium-contaminated soil by Cold Top ex situ vitrification. Demonstration tests were performed on soils from two sites, containing residue from two types of chromite-ore processing. The sites were selected by NJDEP under an ongoing program to clean up over 150 hexavalent-chromium-contaminated sites. The primary objective of this demonstration was to determine if the waste processed by the Cold Top vitrification system meet the Resource Conservation and Recovery Act (RCRA) definition of a nonhazardous waste based on leachable chromium content in the waste. The toxicity characteristic leaching procedure (TCLP) was performed on both treated and untreated waste to evaluate if the Cold Top vitrified soils meet the above objective. Excavated soils from two sites were crushed, sieved, dried, and amended with carbon and sand and then shipped to a Cold Top vitrification plant. Cooled castings of the vitrified products were crushed and grounded for chemical analyses. The TCLP test results confirmed the effectiveness of the treatment. Analysis of operating costs indicated the Cold Top treatment cost of chromium-contaminated soil range from $80–207 depending on disposal costs and potential credit for sale of vitrified products.