SITE DESCRIPTION
The Valleycrest Landfill Site is located at 950 Brandt Pike. The site consists of an area of approximately 100 acres that is separated into eastern and western portions by north-south-trending Valleycrest Drive. The eastern portion of the site consists of approximately 35 acres, and the western portion of the site consists of approximately 65 acres. The site is located above the Great Miami Aquifer, which is a sole-source aquifer for the City of Dayton.
The site is located in a mixed urban, industrial, and residential area. The site is bordered on the east and northeast by a residential neighborhood, on the north by several residences, on the southeast by commercial and residential structures and Valley Pike, and on the southwest by the CSX railroad property and residences. The site is bordered on the west by two residences and several industrial facilities, including the Brandt Pike petroleum terminals, Van Dyne Crotty Inc., industrial cleaner facility, and the Hotop demolition landfill.
The site is currently owned by the Keystone Gravel Company of Dayton, Ohio, and was operated as a sand and gravel quarry from before 1935 until the 1970s. In 1966, the site began accepting solid waste, and later, industrial waste, including hazardous waste drums in the eastern portion of the site (Area 1). Filling in the eastern portion of the site continued until approximately 1970. In 1970, the site began accepting waste in the western portion of the site (Area 5) and continued until approximately 1975.
SUMMARY OF COMPLETED REMOVAL ACTIVITIES
Area 5 Drum Removal
From November 1998 through July 2001, a removal action involving the removal of subsurface hazardous waste drums, drummed contents, and industrial waste was completed. The work was conducted pursuant to a U.S. Environmental Protection Agency (EPA) Administrative Order by Consent (AOC) signed by the Valleycrest Removal Action Coalition (VRAC), and dated September 10, 1998.
In Area 5, a total of 26,986 subsurface drums were removed by VRAC contractors from the 82 50- by 50-foot grids, identified as removal action areas based on geophysical anomalies. Drums containing hazardous waste solids (containing combinations of polychlorinated biphenyls [PCB], ignitable waste, sulfides, and/or Toxicity Characteristic Leaching Procedure [TCLP] trichloroethylene [TCE], vinyl chloride, lead, tetrachloroethylene [PCE], benzene, methyl ethyl ketone [MEK], and heptachlor epoxide) accounted for the majority of the total drums removed in Area 5. Drums containing any measurable liquids (containing combinations of flammable liquids, PCBs, and/or TCLP TCE, vinyl chloride, PCE, benzene, MEK, arsenic, barium, cadmium, chromium, and lead) accounted for less than 3 percent of the total drums (totaling approximately 6,700 gallons collected). Liquid waste from an underground storage tank and rinse water used to aid pumping drummed liquids accounted for 2,845 gallons and approximately 4,500 gallons, respectively.
Excavation, stockpiling, and sampling of all nondrummed material was conducted throughout the Area 5 removal to characterize the material and determine the appropriate disposition. Material below RCRA and Toxic Substances Control Act regulatory limits was backfilled. TCLP volatile organic compound (VOC)-impacted material was maintained on site (pending on-site treatment) and other TCLP-impacted soil and debris was sent for off-site disposal. An estimated 40,000 cubic yards of TCLP VOC-impacted soil and debris (greater than TCLP regulatory limits for TCE and PCE) were stockpiled into 7 stockpiles on site for pending VE treatment or backfilling. In addition, approximately 6,900 tons of TCLP TCE soil/debris, 280 tons of TCLP chlordane soil/debris, 320 tons of TCLP lead soil/debris, and 3,790 tons of PCB soil/debris were transported for off-site hazardous waste disposal.
Area 1 Drum Removal
From February 25 through November 15, 2002, a removal action involving the removal of subsurface hazardous waste drums and drummed contents was completed in Area 1. The work was conducted pursuant to a U.S. EPA AOC signed by the VRAC dated September 10, 1998. On December 12, 2001, U.S. EPA approved the Final Area 1 Drum Removal Work Plan.
In Area 1, a total of 15,622 subsurface drums were removed by VRAC contractors from the 62 50- by 50-foot grids, identified as removal action areas based on geographic anomalies. Drums containing hazardous waste solids (containing combinations of PCBs, ignitable waste, and/or TCLP TCE, PCE, MEK, benzene, lead, vinyl chloride, 2,4-D, cadmium, and chloroform) accounted for 95 percent of the total drums removed in Area 1. In addition, drums defined as RCRA empty drums totaled 4 percent. Drums containing any measurable liquid (containing combinations of flammable liquid, PCBs, and/or TCLP TCE, PCE, MEK, or lead) accounted for less than 1 percent of the total drums (totaling approximately 2,250 gallons collected). The excavated drums not containing liquids were shredded and placed into rolloff boxes for disposal. A total of 77 rolloff boxes were filled with shredded drums and sent for off-site disposal.
Excavation, backfilling, and sampling of all nondrummed material was conducted throughout the Area 1 removal to characterize the material and determine the appropriate disposition. A total of 52 grids were sampled by the VRAC contractor. A total of 17 grids showed TCLP TCE contamination and one grid showed a combination of PCBs and TCLP TCE contamination. The TCLP TCE contaminated material was left in situ for on-site treatment. During intrusive work activities, VRAC contractors conducted perimeter air monitoring using real-time gas chromatographs (Scentograph Plus II units) at three downwind and one upwind locations.
Landfill Gas System
Due to subsurface landfill gas levels at the property perimeter exceeding 5 percent methane (methane is explosive between 5 and 15 percent) and pursuant to an U.S. EPA AOC dated September 10, 1998, VRAC contractors initiated work on the installation of a perimeter landfill gas (LFG) abatement system in June 1998. Seven perimeter LFG extraction systems have been installed (along the northern, eastern, southern, and southeastern site perimeters) and manifolded into an enclosed flare. VRAC contractors have conducted 2 emission stack testing events, the last one in October 2002. The LFG abatement system is operated on a daily basis (currently 4 cycles of 3 hours ‘on’ and 3 hours ‘off’) and monitored on a weekly basis. All property perimeter compliance gas probes are less than 5 percent methane. The operation of the landfill gas system is written in the EPA-approved Landfill Gas Operation and Maintenance (O&M) Plan dated September 30, 2003.
Area 5 Soil/Debris Stockpiles
In March 2002, the seven original stockpiles, (stockpiles 1, 2, 3, 4, 7, 8, and 11) were broken up into 44 cells for pre-treatment sampling and analysis for TCLP VOCs. The sample from each cell consisted of a 5-point composite, with two aliquots collected at a depth of approximately 2 to 4 feet and three aliquots collected at a depth of approximately 8 to 10 feet. All sample results representing the material from stockpiles 1, 2, 7, and 11 were below regulatory criteria. Four cells from stockpile 3, three cells from stockpile 4, and six cells from stockpile 8 were also below TCLP criteria. The clean portions, excluding an 8-foot buffer of clean soil and debris adjacent to impacted cells, were subsequently backfilled on site. The remaining cells, including two from stockpile 3, six from stockpile 4, and two from stockpile 8 were subjected to VE treatment.
Operation of the VE treatment system was initiated on August 8, 2002. A stack test was conducted on the VE treatment system acid scrubber in October 2002, and the data were reviewed by an U.S. EPA technical team. VE treatment was initiated in all three stockpiles at the same time and operated a total of 1,555 hours during 11 weeks of operation up to the point of post-treatment sampling in late January 2003. Sampling was performed on the ten cells that exceeded TCLP regulatory criteria for VOCs. Consistent with the March 2002 pre-treatment sampling, each cell consisted of a 5-point composite sample, with two aliquots collected at a depth of 3 feet and three aliquots collected at a depth of 9 feet. Analytical results showed two cells from stockpile 3 and six cells from stockpile 4 still exceeding TCLP regulatory criteria for TCLP TCE. In addition, three of the stockpile 4 cells also exceeded for TCLP vinyl chloride. The two cells in stockpile 8 below TCLP regulatory criteria were backfilled on site.
Dewatering and additional VE treatment activities were conducted from March through August 2003 on the impacted cells in stockpiles 3 and 4. A second round of post treatment sampling was conducted in August 2003, following the same sampling protocols as in January 2003. Post treatment analytical results showed the remaining two cells in stockpile 3 having TCLP concentrations below TCLP regulatory criteria. Stockpile 4 resampling showed 4 of the 6 resampled cells having TCLP concentrations below TCLP regulatory criteria. The six cells having below TCLP regulatory criteria were backfilled on site. The soil/debris within the two cells having above TCLP TCE regulatory criteria (approximately 3,300 cubic yards) were loaded onto trucks for off-site disposal.
In-situ soil vapor extraction continues in Area 1, 2, and 3. Treatment in sub-groups 1A and 1B is almost complete with treatment continuing on one of the eight grids. Area 2 contains six grids. Treatment continues on four of those six grids. Two grids in Area 3, subgroup 3A, are also continuing treatment. Three grids remain to be treated in subgroup 3B.
July 14, 2008 Update: Operation and monitoring of the perimeter landfill gas extraction system continues. This is the only current removal activity at the site since soil vapor extraction work was completed. Monthly monitoring reports will be posted in the documents section.
January 5, 2009 Update: The Emergency Contingency Plan box was relocated from the trailer that CRA once used to the telephone pole just inside the Site entrance (see attached picture in images section of website).
Monthly Reports including Landfill Gas monitoring results are posted in the documents section of this website.
