WRRCSR No.1:10:83 Decontamination of Chromium Contaminated Soil and Water: Pearl Harbor Naval Shipyard, Pearl Harbor, Hawaii, Phase 2

Abstract

Phase 2 of this project represents the analytical monitoring of an estimated 64,800 ft^3 (1,835 m^3) of chromium-contaminated soil, classified as a hazardous waste (>5 mg/l chromium extract concentration as measured by the standard EP toxicity test), that was treated at the Pearl Harbor Naval Shipyard during a two-month period in late 1982. Although the treatment process details (wash-water-detention times, number of wash-water-flow through times, and type and amount of chemicals) were the contractor's proprietary information, the analytical monitoring treatment process essentially followed the general treatment methods developed in Phase 1 (laboratory and pilot plant studies). The treatment performed by Advanced Environmental Consultants, Inc., of Pittsburgh, Pennsylvania consisted of utilizing 2 yd^3 (1.53 m^3) modified dumpsters as the soil receptacles, using upflow/ downflow washing to leach the chromium from the soil, adding a reducing agent to chemically reduce chromium Cr+6 to Cr+3, raising the pH to approximately 8.5 to precipitate the chromium from solution and to dewater the chromium laden sludge. Each processed soil batch (nearly all 2 yd^3 dumpster units) were monitored for chromium extract. Only 35 of approximatley 1200 dumpster loads were above the 5-mg/l limit, and these were reprocessed.