A FEDERAL SUPERFUND SITE IN EAST DAVIS
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CURRENT AND FUTURE WORK AT THE SITEThermal Treatment
The cornerstone of the proposed remedy is thermal treatment which will consist of underground heating at high temperatures using electrical energy to remove contaminants that are a continuing source of contamination to the groundwater. The heat will either degrade the COCs or vaporize them for capture and subsequent treatment above ground. Vapor controls, including air monitoring, an impermeable layer of plastic over the source area, and soil vapor collection and treatment, will be integral to the thermal treatment process. Thermal treatment will begin some time in 2008. It is predicted to take about a year for the heat treatment to be completed. The pump and treat system will continue indefinitely, probably several decades after heating to treat the remaining groundwater to drinking water standards.
There were several concerns related to the heat treatment voiced by community members and the FFSOG in meetings with EPA. They included questions as to safeguards to ensure full vapor containment, response in case of a leak, response in case of power failure, and air monitoring.
To ensure full vapor containment, the plan is to maximize underground thermal destruction using appropriate temperatures. Toxics that do escape underground destruction will be trapped under a plastic cap for extraction and subsequent treatment. If a leak occurred, the heating system would immediately shut off while the vacuum system continued to extract vapors until the heat ramped down. Project personnel would also be immediately notified. In case of power failure in the primary source, auxiliary sources would run the system until the primary power could be restored or the system shut down. Air monitoring would consist of continuous ambient air monitoring along with other forms. Further details will be worked out when a heating vendor is brought on board in the next month or so.
Bioremediation Field Study
In response to comments from the FFSOG, EPA conducted an anaerobic bioremediation field study to examine effects of bioremediation on the chemicals of concern, nitrates, and sulfates. Beer fermentation process waste plus a tracer were injected into a monitoring well and groundwater characteristics were monitored in this and a near-by down-gradient well. Some of the objectives were to confirm that anaerobic conditions can be established and maintained; estimate the extent of the treatment zone; and to evaluate the effectiveness of the treatment. The results of the study did not satisfy the objectives. While the results show inducement of reducing conditions, the extent of these conditions could not be determined. There was no evidence for nitrate or sulfate reduction beyond the injection site. There was no conclusive evidence for reduction of the target COCs of concern at the injection site or beyond. EPA has put this method on hold for the time being.
Redevelopment at the Frontier Fertilizer Site
In July 1999, the City of Davis was awarded by EPA a grant of $100,000 to develop a plan for future redevelopment of the Frontier Fertilizer site. The grant provided Davis with an opportunity to return this site to productive use after clean-up is completed. The FFSOG was asked to review the proposal and to make comments and recommendations. After a series of public meetings and workshops, three ideas were presented: light industry, office park, or a combination with quasi-public uses. Finalization and implementation of any plan depend on EPA’s future decisions regarding the final remedy for the soil and groundwater clean-up.
Proposed Development of RAMCO Property North of the Site
In early 2000, RAMCO Enterprises submitted a proposal for a light industrial/business park in Mace Ranch on the property lying to the north and west of the Frontier Site. EPA has a number of monitoring and extraction wells in that field and will require continued access to the field for many years. In meetings held concerning the development, issues and concerns arose in regard to the project in view of EPA’s efforts to address the contamination in the soil and groundwater associated with the site. One of the original concerns was that development on RAMCO’s property would interfere with EPA’s ability to conduct clean-up activities at the site. Homeowners in the area were also concerned that the development should not interfere in any way with EPA’s work.
As a response to these and other issues, in 2001 the City, RAMCO, EPA and the FFSOG agreed to certain conditions for approval of the development. These included a prohibition of construction in the lots containing EPA’s monitoring and extraction wells and a requirement that the roadway be constructed with two cul-de-sacs ending on either side of the area of concern. Another condition was that the applicant must coordinate all construction activities with EPA and that EPA’s work has priority.
RAMCO officials did decide to move ahead with construction of the roadway and underground utilities in preparation for subsequent development of the industrial/business park. This despite the fact that EPA had made it clear that any work that might interfere with their access or ability to carry out their mission to cleanup this site would be a violation of CERCLA and any improvements constructed by RAMCO on the property that interfere with EPA would be removed, modified, or disabled by EPA and their contractors if necessary. The cost of this removal and future replacement would be borne by the developer. RAMCO submitted several proposals to complete the road (eliminate the cul-de-sacs and build a road through the well field) over the next few years, but these were denied by EPA and the City of Davis.
In 2005, Target Corporation submitted a proposal for development of a Target store and some satellite stores on a portion of RAMCO’s property. That proposal went to the ballot in November 2006 and was narrowly approved.
The footprint for the Target development recently approved by the voters will impact locations of some of the existing wells and other components of the extraction and monitoring systems in the field. These will have to be modified or replaced with new wells by Target’s consultants with close oversight by EPA, the State and the FFSOG. Modifications to the wells must be carefully planned to minimize disruption to clean-up work at the site and to provide for future access for maintenance and monitoring of the system. EPA and the FFSOG have worked to develop a Scope of Work (SOW) for Target’s contractors to ensure that the proposed well replacements will not interfere with EPA’s focus on the remediation process and that the new wells will provide essential hydrologic and water-quality information of the same or better quality as the abandoned wells.
The FFSOG is committed to ensuring that pressures to move ahead with construction of the Target development do not in any way hinder EPA’s work in the clean-up process or compromise future clean-up work at the site.
For informataion regarding the Frontier Site or the FFSOG contact Pam Nieberg.