WRRCSR No. 1.10:83 Decontamination of Chromium-Contaminated Soil and Water: Pearl Harbor Naval Shipyard, Peart Harbor, Hawai'i, Phase 2

Abstract

Phase 2 of this project represents the analytical monitoring of an estimated 64,800 ft3 (1 835 m3) 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 yd3 (1.53 m3) 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 yd3 dumpster units) were monitored for chromium extract. Only 35 of approximately[sic] 1200 dumpster loads were above the 5-mg/ℓ limit, and these were reprocessed.