The Charlie Burch Site is owned by an independent landowner. The Site was used for waste disposal by an independent hauler in the mid-1960s, who used it to dispose of waste generated by several manufacturers. In 1967, the Site was closed by the landowner by order of a Montgomery County judge. In the early 1980s, the county constructed a drainage channel through the Site, and Rohm and Haas and several other parties were ordered to conduct a site investigation and to develop a closure plan. The result was an engineered landfill constructed onsite that was approved by the state.
In the early 1990s, the Texas Water Commission asked Rohm and Haas to conduct additional soil and groundwater investigation work. The site was accepted into the Voluntary Cleanup Program (VCP) administered by the Texas Natural Resource Conservation Commission (TNRCC) in 1997 and Rohm and Haas began site investigations under this program. These investigations detected the presence of an organic compound named 1,2-dichloroethane (1,2-DCA) that had migrated off the site and into the shallow groundwater zone between 25 to 65 feet below the surface. The groundwater flow in this zone is advancing in a southeasterly direction. The investigations found concentrations of the compound that were above the drinking water standard of 5 parts per billion.
The drinking water supply for the area comes from an aquifer that lies approximately 290 to 425 feet below the surface, much deeper than the zone where 1,2-DCA has been found. No detectable levels of 1,2-DCA have been found in water wells installed in this deeper aquifer when sampled and tested by independent third parties and the Texas Commission of Environmental Quality (TCEQ). The TCEQ, however, still requires that a remediation plan be developed and implemented even when drinking water is not affected.
We believe there are no reasons for anyone to be concerned. Investigations revealed that groundwater moving southeast from the site contained a compound called 1,2-DCA. The 1,2-DCA is found in a narrow band between approximately 25 feet and 65 feet beneath the surface. Extensive testing shows that there is no soil contamination either at the surface or within approximately 25 feet of the surface.
Data from studies indicate that the 1,2-DCA does not represent a risk to people in the area because the 1,2-DCA is located in a zone NOT used for drinking water supplies. The water used for drinking comes from a zone several hundred feet deeper. Water supplies also are routinely tested by municipal authorities to make sure that the water they provide is safe to drink. Being 25 feet or so beneath the ground, the 1,2-DCA is isolated from the surface by clean soil, so there is no risk that anyone could come into direct contact with it. Finally, multiple studies have shown that the concentrations of 1,2-DCA in the groundwater are so low that they are unlikely to move through the soil and to the surface at levels that would represent a health concern.
We are required to provide notifications under the TCEQ’s rules for the Voluntary Cleanup Program, because the groundwater in the shallow water bearing zones has concentrations of 1,2-DCA that exceed water quality standards.
Rohm and Haas is one of several companies whose waste was taken to the Charlie Burch Site in the 1960’s. We have agreed to assume the role of lead party in the site investigation and cleanup under the VCP.
Please contact Brad Wilkinson of Rohm and Haas Texas (a subsidiary of the Dow Chemical Company) at email@example.com. The TCEQ Project Manager for this project is Joe Bell, who can be reached at (512) 239-6753 or firstname.lastname@example.org. They will ensure that your questions are answered and your concerns addressed.
The equipment used to perform the well installation and injection activities include compact drilling rigs, support trucks, and a trailer containing the injection equipment, such as tanks, hoses, and pumps. Work crews consist of 4-5 people during drilling and up to 6 people during injection activities.
The injections performed use much lower injection pressures compared to any process used in the oil and gas industry. The injection approach specifically uses low pressures and low injection rates to prevent fracturing of the soil and the project team monitors the down-hole injection pressures continuously during injection of materials to avoid over-pressure situations that could lead to fracturing.
Rohm and Haas is committed to restoration of site conditions to pre-well installation and injection activities. To this end, a pre-survey will be conducted to document the conditions of the areas where work is planned. At the completion of the work in a particular area, a post-survey of the area will be conducted, and restoration work will be performed to repair any property that had been damaged, including but not limited to curbs, sidewalks, and landscaping.
The cleanup of the groundwater will require at least five years. Some portions of the plume may require longer to cleanup than others. Response Action Effectiveness Reports are due to TCEQ every third year after startup of treatment to provide an update on cleanup status, and those reports will be available for review on this website.
In 1999, approximately 91,000 cubic yards of material were excavated from the site, and hauled away to licensed secure disposal sites outside of the area. The former disposal area was backfilled with clean fill, graded and capped with low permeability soils.
Despite having no known history of using 1,2-DCA and suspecting that others may have been the source of the compound, Rohm and Haas nevertheless responded by building two groundwater recovery systems to remove the 1,2-DCA from the groundwater. One is located at the former disposal area and the other is located towards the downgradient edge of the groundwater plume. The former disposal area system was redesigned and replaced with a new system to improve performance and to enhance capture of the on-site 1,2-DCA plume. This upgraded system became operational in February 2012. Since start-up, the systems have removed and cleaned over 300 million gallons of water through June 2016.
This removal action, combined with the active groundwater recovery systems, has reduced the levels of 1,2-DCA in groundwater. Investigations to identify the precise limits of the impacted groundwater were completed in 2007. Finally, Rohm and Haas submitted to TCEQ, and TCEQ approved in April 2011, a Final Response Action Plan, which presents the proposed response actions for dealing with 1,2-DCA in the groundwater. The main features of the plan include:
Removal of significant amounts of 1,2-DCA through continued operation and optimization of the groundwater recovery (pump and treat) systems installed at the Site;
Maintenance of groundwater recovery and treatment systems to limit the migration of the 1,2-DCA plume;
Ongoing evaluation of other treatment options at the Site;
Treatment of groundwater between the Site and the Subdivision, and between the Subdivision and the 13-Acre Tract, using injections of food-grade materials to enhance natural processes of 1,2-DCA removal; and
Continued use of food-grade material treatment systems as needed to achieve remediation goals for the Site.
To address portions of the groundwater plume between the Site and the Subdivision, and between the Subdivision and the 13-Acre Tract, a process called enhanced anaerobic bioremediation (EAB) has been tested and approved for use at the Charlie Burch site by the TCEQ. The EAB application involves the injection of harmless organic materials, including vegetable and soybean oils, into the underlying groundwater to provide a long-term source of food that enables the microbial populations to more effectively decompose DCA. As groundwater flows through the treatment zones, microorganisms break them down converting them to harmless end products.
The EAB application is being implemented in a phased approach to facilitate optimization and incorporation of process improvements into subsequent phases. This phased approach allows for flexibility in treating areas predicted to take longest to clean up. The EAB application is designed to inject sufficient organic materials and amendments to persist in the groundwater for up to 4 years, requiring replenishment of those materials (re-injection) on an on-going basis until the groundwater is determined to be clean by the TCEQ. Injection activities associated with the implementation of Phases 1 and 2 of the EAB application were conducted between March and June 2012. Phase 5 EAB applications were completed in early 2014, and Phase 4 EAB applications were completed in November 2016. Phase 3 EAB applications remain pending. Performance monitoring is conducted periodically to measure application effectiveness.
Several treatments may be necessary to replenish the treatment materials before the EAB process is complete.