INERT DISPOSAL AREA
SITE DESCRIPTION
The Inert Disposal Area encompasses approximately 20 acres and is located west of C Road, north of Line 3A in the west central part of the installation. It once included an inert (sanitary) landfill, a burning ground, a metal salvage operation, the former Blue Sludge Lagoon, wastewater sludge drying bed, cap extension area (CEA), and an earthen holding area formerly used to store sludge from Line 3 and Line 800.
Soils from other restoration sites are transported to the inert disposal area for segregation according to health risk. Soils classified as a high health risk are placed in the CAMU (Trench 7) to be held for treatment. The CAMU was designated by the USEPA via a letter dated March 8, 1996. Soils classified as a medium health risk are placed in a RCRA-type lined cell (Trench 6) and soils that are classified as a low health risk are placed underneath the overall cap at the inert disposal area.
The inert landfill was in operation from 1941 to September 1992. It employed the trench-and-fill operation technique. Trenches 1 through 5 were filled primarily with sanitary landfill materials such as unsalvageable or unrecoverable materials (cafeteria and residential refuse and garbage, broken pallets, plastic, tin cans, and scrap wood/lumber paper, cardboard, and asbestos insulation in double-lined plastic bags). Ash from OB and incineration was also placed in the landfill. In 1980 a Part A permit was received for the inert landfill and the Blue Sludge Lagoon. Interim status was granted that year. During 1997 a low permeability synthetic cap was placed over trenches 1 through 5 (approximately 17 acres). This area was seeded in 1998.
In 1984 the lagoon holding area was closed following the transfer of the blue sludge to a concrete-lined sludge drying bed, where it remained until January 1997. The excavated area was backfilled and capped with clay and a vegetative cover was established. In 1997 the blue sludge was excavated from this drying bed and deposited into Trench 6. In 1997 explosives- and metals-contaminated soils from a 1993/1994 multi-site sump removal project were placed in Trench 6.
The north end of Trench 5 contains special waste, such as ash from the contaminated waste processor (CWP) (IAAP-024), explosive waste incinerator (EWI) (IAAP-025), and OB of explosives and explosives-contaminated wastes.
In April 1988 this area was capped and the Resource Conservation and Recovery Act (RCRA) closure plan was completed. In February 1997 the plan was amended to address sampling issues. In 1997 during routine sampling radionuclides were found in GW samples and were determined to be within normal background levels for IAAAP and within safe limits.
In 1996 IRAs (soil removal and capping) at the inert disposal area, Former Line 1 Impoundment Area (IAAP-016), and the Line 800 Lagoon (IAAP-044) were initiated and were completed in 1997.
Soil and debris from the burning grounds was placed underneath the inert landfill cap or in Trench 6, whichever was appropriate, based upon contamination levels. In 1997, the cap construction was completed over trenches 1 through 5. Soils from the East Burn Pads, North Burn Pads, North Burn Pads Landfill and Fire Training Pit were placed into trenches 6 or 7. VOC-contaminated soils from the Fire Training Pit were removed and treated via a low temperature thermal desorption (LTTD) unit at Trench 6. On March 8, 1996 Trench 7 was designated as a CAMU by the USEPA.
In FY02, approximately 6,000 cy of soil contaminated with explosives and metals and stored in the CAMU were treated and segregated per the Interim Soil ROD.
An ESD, signed in 2003, specified enhanced biological treatment as the primary remedy for explosive-contaminated soils.
GW monitoring and long term maintenance costs associated with sites IAAP-001, 002G, 003G, 004G, 010G, 012G, 016, 020, 020G, 032G, 039G, 044G, and 046 are captured in this site.
To date, approximately 205,301 cy of soil have been taken to the inert disposal area. Of this volume,
- 72,861 cy was placed as random fill under the cap of the inert landfill (i.e., Trenches 1-5);
- 77,763 cy was placed in Trench 6 (i.e., 71,450 cy IRP soil; 6,313 cy FUSRAP soil);
- 15,448 cy was placed in Trench 7 for treatment (i.e., 15,207 cy IRP soil; 241 cy FUSRAP soil); and
- 39,229 cy was placed in the CEA (i.e., 37,412 cy IRP soil; 1,817 cy FUSRAP soil).
The soil volume treated to date includes a total of 37,959 cy. This treated soil includes
- 8,854 cy which has undergone biotreatment for soils,
- 13,005 cy which has undergone metals stabilization,
- 15,448 cy which has undergone chemical treatment for explosives, and
- 652 cy which has undergone low temperature thermal desorption.
A portion of this volume came from FUSRAP screening areas (IAAP-012, 032, 036, and 037). Soils from Trench 7 have been transferred to Trench 6. Some treated soils, such as those treated with LTTD, were sent directly to Trench 6 immediately after treatment.
During the August 2004 radiological screening of the inert disposal area conducted by FUSRAP, one isolated area of radiological contamination was identified. This area was limited to a small object and the soils around the object (approximately one square yard). Analysis identified that the object contained Cesium-137. The soil where the object was found originated from remediation activities at the West Burn Pads Area (IAAP-032). The area was sufficiently covered with soil to eliminate exposure.
CLEANUP STRATEGY
This site is under the PBC awarded in 2004. Actions at this site will manage remediation waste awaiting treatment and capping, continue to receive contaminated soil from other sites, to control and treat storm water and leachate and maintain existing cap.
After all contaminated soil has been treated, the plan is to excavate and move the CAMU to Trench 6. Trench 6 and the CEA will be capped. After closure, leachate management and cap maintenance will continue. Programmed costs also include installation-wide remedial action (operation) (RA(O))/long-term management (LTM) for GW monitoring and five-year reviews.
STATUS
RRSE RATING: Medium
CONTAMINANTS: Metals, Explosives
MEDIA OF CONCERN: Soil
COMPLETED IRP PHASE: PA/SI, IRA, RI/FS, RD
CURRENT IRP PHASE: RA(C)
FUTURE IRP PHASE: RA(C), RA(O)