Record of Decision System (RODS)
RENTOKIL, INC. (VIRGINIA WOOD PRESERVING DIVISION)
|Site Name:||RENTOKIL, INC. (VIRGINIA WOOD PRESERVING DIVISION)|
|Address:||OAKVIEW AVE & PEYTON STS|
|City & State:||RICHMOND VA 23228|
|NPL Status:||Currently on the Final NPL|
|ROD Type:||Record of Decision|
|Media:||Soil, Sediment, Debris, Sludge, GW, SW|
|Contaminant:||VOCs, Other Organics, Metals|
|Abstract:||The Rentokil Virginia Wood Preserving Division site is a former wood treating facility located in Henrico County, Virginia. Land use in the area is mixed light industrial, commercial, and low density residential. In addition, site features include woodlands, wetland areas, a floodplain, Talley's Pond, and an unnamed tributary referred to as North Run Creek. Residents living just north of the site use the municipal watersupply system to obtain their drinking water. From 1957 to 1990, onsite wood treatment operations used products such as PCP, fuel oil, chromium zinc arsenate, copper chromated arsenate (CCA), fire retardant, creosote, and xylene. Wastes from the early wood treatment operations reportedly were discharged to the blowdown sump, which is an open earthen pit used for the discharge of waste processing fluids, located to the north of the treatment cylinders. In 1963, the State required that the pit be cleared, cleaned, and replaced with the concrete holding pond due to fish kills in Talley's Pond. In 1976 or 1977, approximately 1,100 to 1,400 pounds of CCA, that was allowed to precipitate in a process tank before it was rendered unusable, was disposed of in a pit located along the north fence line of the site. When soil was excavated during the removal of one of three production wells, a black substance, assumed to be creosote, was observed seeping into the wall of the excavation at a depth of approximately five feet. In 1987, the contents of the covered holding lagoon were transported to offsite treatment and disposal facilities. Because clean closure of the lagoon was not attempted, and the cover was not replaced, the lagoon re-filled with water. As a result, a hazardous K001 sludge, containing creosote and/or PCP, remains at the bottom of the lagoon due to the treatment of wastewater from the wood preserving processes. Throughout site operations, treated wood was stored in open areas onsite and was allowed to drip onto the ground, contaminating the soil. In 1987, sampling during the RI indicated elevated levels of arsenic, chromium, copper, and zinc in the sediment and surface water of North Run Creek. In 1989, the owners of Talley's Pond dredged the sediment and sludge that had accumulated at the bottom of the pond, placed them around the pond, and seeded the area. In 1990, when onsite operations ceased, a cover was placed over the drip pad to shield it from precipitation, and a roof was constructed over the concrete holding pond. In 1991, all of the wood treatment equipment was removed offsite, and a layer of clean gravel was placed over the entire surface of the site. In 1992, EPA required Rentokil to design and construct sediment control structures to prevent additional migration of sediment containing metals from the site into the North Run Creek, and to provide site security by posting the area with warning signs and maintaining the existing fencing. In addition, the CCA disposal areas were covered with heavy duty plastic sheeting anchored with a gravel covering to minimize the continued migration of contaminated sediment. This ROD addresses the contamination in several site areas, including the area of the former blowdown sump, the drip pad, the unlined pond, the CCA Disposal Area, the Fill Area, the perched and saprolite units, the three wetland areas, North Run Creek, and the remaining structures onsite. The primary contaminants of concern affecting the soil, sediment, debris, sludge, ground water, and surface water are VOCs, including benzene, toluene, and xylenes; other organics, including dioxin, PAHs, and phenols; and metals, including arsenic and chromium. SELECTED REMEDIAL ACTION: The selected remedial action for this site includes demolishing, decontaminating, and disposing of existing structures offsite; excavating and incinerating offsite approximately 70 yd of K001 sediment and sludge, with prior onsite treatment using dechlorination, if the level of dioxins/furans would cause a violation of the incinerator's RCRA permit; extracting and treating surface water in the unlined pond onsite using carbon adsorption, with onsite discharge of residuals to North Run Creek and closure of the pond; dewatering, excavating, and consolidating approximately 7,200 yd of surface soil from the three wetland areas to the area to be capped; treating the pond water in an onsite water treatment system, prior to discharge to North Run Creek; re-vegetating the excavated wetland areas; constructing a slurry wall, which includes a dewatering systemaround the cap; treating contaminated ground water onsite using carbon adsorption, with precipitation of metals, if necessary, with onsite discharge of the treated water to North Run Creek; regenerating the spent carbon offsite, with offsite disposal of sludge generated during the treatment process in an approved facility; excavating and treating onsite approximately 5,150 yd of the soil removed during installation of the dewatering system and slurry wall, along with soil located in the CCA Disposal Area and Fill Area, and the DNAPL-contaminated soil using low temperature thermal desorption to remove PCP and carcinogenic PAHs; treating onsite the remaining soil which exceeds the arsenic cleanup level using chemical fixation; disposing of and capping the treated soil onsite, with disposal of any treated soil which does not meet the established cleanup levels in an offsite RCRA facility; disposing of excavated drums from the Fill Area offsite; excavating and disposing of sediment in North Run Creek onsite; excavating, treating, and disposing of sediment in and around Talley's Pond offsite; providing for a contingency remedy to treat onsite the K001 waste from the unlined pond using dechlorination, if the level of dioxins/furans exceed the level which the incinerator is permitted to accept; monitoring ground water; and implementing institutional controls, including ground water and land use restrictions. The estimated present worth cost for this remedial action is $10,907,000, which includes an estimated annual O&M cost of $72,200 for 30 years. The estimated present worth cost for the contingency remedy is $1,499,500. PERFORMANCE STANDARDS OR GOALS: Chemical-specific cleanup goals for the site are based on a human health risk of 10[-6], and include arsenic 33 mg/kg; PAHs 48 mg/kg; and PCP 48 mg/kg. INSTITUTIONAL CONTROLS: Institutional controls, including ground water and land userestrictions, will be implemented to prohibit use of the ground water and residential development of the site.|
This remedy will address all of the media impacted by the contamination at the Site. It is not warranted at this time to divide the Site into smaller components called operable units to address individual media. Based on the information derived through the Remedial Investigation, the CCA Disposal Area, Fill Area, and the dense nonaqueous phase liquids (DNAPLs) pose principal threats to human health. Since wastes will be left in place, long-term monitoring of the ground water must be performed.
The selected remedy includes the following major components:
. Demolition, decontamination, and offsite disposal of the existing structures.
. Excavation, dechlorination treatment (if necessary), and offsite incineration of K001 waste from the unlined pond. Removal and onsite carbon adsorption treatment of surface water in the unlined pond.
. Construction of a RCRA Subtitle C cap.
. Excavation and onsite disposal of surface soil beyond extent of cap.
. Excavation, low temperature thermal desorption (LTTD) and fixation treatment, and onsite disposal of CCA Disposal Area, Fill Area, and the DNAPL soil within 25 feet of concrete drip pad, unlined pond, and former blowdown sump.
. Offsite disposal of drums excavated from the Fill Area.
. Construction of a slurry wall.
. Construction of a dewatering system within the cap/slurry wall; onsite carbon adsorption treatment of ground water.
. Excavation and onsite disposal of sediments in the oxbow of North Run Creek. Sampling of sediments in Talley's Pond and those sediments previously dredged by the owner with excavation, treatment, and offsite disposal if sediments exceed cleanup levels.
. Institutional controls to prohibit residential development of Site and use of the ground water at the Site.
. Long-term ground water monitoring.
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