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Title: The Excavation and Remediation of the Sandia National Laboratories Chemical Waste Landfill

The Chemical Waste Landfill (CWL) at Sandia National Laboratories/New Mexico (SNL/NM) is a 1.9-acre disposal site that was used for the disposal of chemical wastes generated by many of SNL/NM research laboratories from 1962 until 1985. These laboratories were primarily involved in the design, research and development of non-nuclear components of nuclear weapons and the waste generated by these labs included small quantities of a wide assortment of chemical products. A Resource Conservation and Recovery Act (RCRA) Closure Plan for the Chemical Waste Landfill was approved by the New Mexico Environment Department (NMED) in 1992. Subsequent site characterization activities identified the presence of significant amounts of chromium in the soil as far as 80 feet below ground surface (fbgs) and the delineation of a solvent plume in the vadose zone that extends to groundwater approximately 500 fbgs. Trichloroethylene (TCE) was detected in some groundwater samples at concentrations slightly above the drinking water limit of 5 parts per billion. In 1997 an active vapor extraction system reduced the size of the TCE vapor plume and for the last six quarterly sampling events groundwater samples have not detected TCE above the drinking water standard. A source term removal, being conducted as amore » Voluntary Corrective Measure (VCM), began in September 1998 and is expected to take up to two years. Four distinct disposal areas were identified from historical data and the contents of disposal pits and trenches in these areas, in addition to much of the highly contaminated soil surrounding the disposal cells, are currently being excavated. Buried waste and debris are expected to extend to a depth of 12 to 15 fbgs. Excavation will focus on the removal of buried debris and contaminated soil in a sequential, area by area manner and will proceed to whatever depth is required in order to remove all pit contents. Up to 50,000 cubic yards of soil and debris will be removed and managed during the excavation of the CWL. As part of the excavation process, soil is being separated from the buried debris using a 2-inch mechanical screen. After separation from the soil, debris items are further-segregated by matrix into the following categories: wood, scrap metal, concrete/aggregates, resins, compatible debris, intact chemical containers, radioactive and mixed waste, and high hazard items. One of the greatest sources of hazards throughout the excavation process is the removal of numerous intact chemical containers with unknown contents. A large portion of the excavated soil is contaminated with metals and/or solvents, Polychlorinated biphenyls (PCBs) are also known to be present. Most of the contaminated soils being excavated will be taken to the nearby Corrective Action Management Unit (CAMU) for treatment and management while a majority of the containers will be taken to the Hazardous Waste Management Facility or the Radioactive and Mixed Waste Management Facility for proper treatment and/or disposal at permitted offsite facilities.« less
Authors:
; ; ;
Publication Date:
OSTI Identifier:
14991
Report Number(s):
SAND99-3020C
TRN: AH200130%%198
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Waste Management 2000, Tucson, AZ (US), 02/27/2000--03/02/2000; Other Information: PBD: 23 Nov 1999
Research Org:
Sandia National Labs., Albuquerque, NM (US); Sandia National Labs., Livermore, CA (US)
Sponsoring Org:
US Department of Energy (US)
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; CHEMICAL WASTES; DRINKING WATER; EXCAVATION; MANAGEMENT; NEW MEXICO; NUCLEAR WEAPONS; POLYCHLORINATED BIPHENYLS; RESOURCE CONSERVATION; SANDIA NATIONAL LABORATORIES; SANITARY LANDFILLS; SCRAP METALS; SITE CHARACTERIZATION; SOURCE TERMS; WASTE MANAGEMENT; WASTES