The Hinds County Wood Preserving Company, Inc. (HCWP) began operations in the early 1960s and ceased operations around 1978. HCWP treated lumber with creosote in two pressure vessels. Remaining on-site as of 11/06/2006 were both pressure vessels (Tanks 2 and 6), three above-ground storage tanks (AST) (Tanks 1, 3, and 5), the facility boiler (Tank 4), and various pieces of equipment and treated lumber. The removal assessment determined 1) that each of the three ASTs contains some amount of material with a collective total of approximately 14,000 gallons, 2) each of the pressure vessels contains some amount of residual creosoting material and one was actively leaking, 3) seven drums of waste oil-water mixture were left on-site, 4) the boiler unit insulation contained asbestos while the pressure vessel’s insulation did not, and 5) equipment contaminated with creosote remained on-site.
The site is drained by several ditches that converge at the northeast, adjacent to Learned Oakley Road, and flow via culverts into Bitter Creek on the east side of the road. The nearest residence is located 120 yards and uphill from the site. The resident maintains a groundwater well on the property, but the house has been connected to a municipal water supply.
Tank 6 was decontaminated and deconstructed
Concrete from the site continues disposal to a C&D landfill.
Metal continues to be decontaminated and sent off-site for recycling.
Excavation continued and the soil has been stored in two stockpiles. When the weather is dry during the day, the piles are uncovered to encourage evaporation of moisture. When the weather is wet or during the night, the piles are covered with plastic to prevent runoff. Approximately 850 yards of contaminated soil were stockpiled by the end of the week.
A sample has been taken from the stockpile for waste profiling and the results have been sent to three disposal companies. The disposal subcontractors will bid separately for the soil, washwater, drums, and mercury-containing equipment.
- Clearing of vegetation and trees to gain access to contaminated areas. (COMPLETE)
- Removal and bulking of contaminated wastes and/or hazardous substances from tanks and drums. (ONGOING)
- Demolition and removal of tanks and removal contaminated materials such as abandoned equipment. (COMPLETE)
- Excavate, stockpile and re-locate the contaminated surface soil. (ONGOING)
- Collect and analyze confirmation samples from the excavated areas. (ONGOING)
- Restore and backfill excavated areas with clean fill. (ONGOING)
- Conduct additional sampling for waste profiling. (ONGOING)
- Additional sampling to confirm extent and boundary of migrated contaminants. (ONGOING)
- Complete excavation
- Begin backfill
- Recieve, review, and approve disposal bids
- Determine usability of the borrow pit
USCG GST supplied a TVA-1000, DataRAM and MultiRAE to conduct air monitoring during the excavation. Soils at one area of the pit during excavation, near and underneath where Tank 3 had stood, yielded a strong “gaseous” smell at depths of 4-5 feet. The TVA registered high concentrations of organics at headspace, but low levels in the breathing zone. It was determined that the high levels of PAHs causing the odor have likely spread to the soil at an indeterminable depth and breadth. The contaminated subsurface soil could likely exceed several thousand yards. For purposes of this removal, it was determined that a backfill of at least two feet would be substantial enough to eliminate the threat of exposure to the subsurface contamination. Considering the greatest PAH concentrations occurred at depths of 3-4 feet, the backfill in this area will be an appropriate barrier. Physical warnings will be placed below the backfill, such as geo-fabric or construction fencing; and Institutional Controls such as a deed restriction against digging in that area of the property will be pursued in order to maintain the protective cover.
Approximately 16,000 gallons of washwater is being held in the frac-tank. This water could be discharged into the creek if it were to undergo an appropriate treatment system. Currently, the best method for treatment would involve the addition of flocculants, removal of sediment, sand filtering, and activated carbon filtering through at least 4 to 5 drums. In order to maintain a low rate of flow to discharge into the creek, the filtering process would require 4 days of operation. The implementation of this treatment will not occur until the bids for disposal have been received and it is determined that this procedure will cost less over the longer period of time.
|
