Cabot/Koppers Site Video Transcript
Hello, I’m Scott Miller the EPA’s remedial project manager for the Cabot-Koppers Superfund Site. We’re here today to give you a guided tour of the Koppers Plant and former Cabot site to discuss past operations at these two areas, past and current cleanups and the current operations of the Koppers plant. Koppers is an active wood-treating plant that impregnates telephone polls with copper chromated arsenic. This wood-treating facility has changed hands many times since its construction in 1916.
Today’s operation owned and operated by Koppers Inc. takes utility poles from railcars, impregnates the phone polls under high temperature and pressure conditions in an enclosed vessel, allows the utility polls to dry over a drip track which collects the dripping CCA solution and removes the utility polls to the property where they await shipment back out into railcars to customers who use them. As part of today’s operation, Koppers operates a watering truck designed to keep the dust from becoming entrained in the air where it may be blown off-site.
Today’s operation is much more environmentally-friendly than past operations have been. Previous operations consisted of impregnating utility polls and other wood items in four separate open-pit unlined lagoons. This approach to wood-treating while consistent with the practice for the time period created groundwater and soil pollution. The previous operations used pentachlorophenol, creosote and copper-chromated arsenic to impregnate the wood. This aerial map shows the approximate location of the four source areas where the wood was treated. Where I am standing is the former North Lagoon. While the pits have been closed soil and groundwater contamination remain. There are current pilot tests that have been conducted and are being conducted at the North Lagoon to determine if certain technologies will be able to address groundwater and soil contamination.
Specifically, a recent pilot test was successfully completed for in-situ biogeochemical stabilization. The concept is to create a reactive chemical box around contaminated soil which contains and prevents dense non-aqueous phase liquids from leaching to soil and penetrating into deeper groundwater aquifers. Permangenate is squeezed into the ground at constant pressure. The liquid permanganate follows the same path that the DNAPL follows when it went down into the soil. Once the permanganate makes contact with the DNAPL, it forms a crust which renders the new compound into a steady-state insoluble compound. This approach in essence changes the DNAPL so that it is immobilized and reacts to be a harmless insoluble precipitate. This technology has been demonstrated at other Superfund sites to be effective in treating DNAPL.
Other technologies that have been deployed at other wood-treating sites and that are being tested are active and passive DNAPL recovery from the Hawthorn and Surficial aquifers.
Here is the current surficial aquifer containment system, it removes groundwater from 8 recovery wells at the eastern boundary of the Koppers Site, treats the groundwater and releases it to the GRU to treat. This system has been in operation since 1995. As part of interim remedial measures to be implemented by December, there will be additional recovery trenches installed closer to the four primary source areas to increase the effectiveness of groundwater capture. In addition, an interim remedial measure to pump and treat contaminated groundwater from areas of the Florida aquifer
The soils that come from this effort along with sediments from an onsite ditch will be blended and made part of a soil solidification/stabilization pilot to take place at the South Lagoon which was one of the source areas. Solidification/stabilization is a technology that EPA and other parties have deployed at numerous Superfund sites across the Country including Brunswick Wood in Brunswick, Georgia. It is a soil treatment that combines contaminated soil with cement or other solidification agent to in effect “freeze contamination in place. In this instance, it would immobilize DNAPL in the soil preventing it from migrating into groundwater aquifers. This pilot test is designed to determine site-specific parameters that would be necessary to determine mixing ratio etc. to optimize such an approach at this particular Site.
One issue related primarily to the former Cabot operations occurred in 1967 when a developer breached the former Cabot lagoons and some of the content of the lagoons made its way to Springstead and Hogtown Creeks. Alachua County through a cooperative agreement with EPA is taking sediment samples in both Springstead and Hogtown Creeks to obtain information related to possible site effects from both the former Cabot and Koppers site operations. The contaminant concentrations found will be included in a human health risk assessment that EPA will conduct. Alachua County will also be conducting a stormwater study at the Koppers Superfund Site.
Beazer East has installed these Floridan aquifer wells along the direction of groundwater flow between the Koppers Site and GRU’s Murphee Wellfield. GRU’s Murphee Wellfield is the souce of drinking water for the Gainesville greater area. These wells are designed to intercept any Koppers site related contamination years in advance of it making its way to the Murphee Wellfield so that action could occur to avoid such an event. It is important to remember that to date no Koppers Site-related contamination has been detected at the GRU Murphee Wellfield. GRU routinely samples and analyzes the groundwater there prior to withdrawl and treatment to ensure that they deliver a clean product to consumers.Here we are at the former Cabot lagoons. All of the former Cabot Site has been redeveloped into a shopping center and multiple car dealerships along the east side of North Main Street, North of 23rd Avenue. Cabot excavated the lagoons in 1994. Since that time, Cabot has operated a groundwater interceptor trench along North Main Street. Groundwater contaminant concentrations have gone down over time. As part of its Five-Year review items, Cabot is evaluating the capture effectiveness of groundwater interceptor trench in capturing contaminated groundwater from Cabot’s operations.