Geothermal Test Facility

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The East Mesa Geothermal Test Facility is an inactive Department of Energy geothermal research facility. It is located in the Imperial Valley, Imperial County, California, approximately 32 kilometers (20 miles) east of El Centro and 2.4 kilometers (1.5 miles) north of Interstate Highway 8.

FACILITY MISSION

In 1968, the United States Bureau of Reclamation constructed the East Mesa Geothermal Test Facility for the investigation and development of geothermal resources in the East Mesa area. The Department of Energy became the site operator in 1978 and continued the site's energy research mission.

The 33-hectare (82­acre) site includes a 2.5-hectare (6­acre), polyvinyl chloride­lined holding pond installed in 1972 for the temporary storage and evaporation of brine blowdown water, and untreated brine extracted in the geothermal exploration process. The Department discontinued geothermal research activities at the site in 1987 as commercial-scale geothermal power developed in the region. Areas requiring remedial action at the site are related to past operations and consist of remediating a storage holding pond, a septic tank, and minor quantities of asbestos in onsite structures.

There are no current or planned nuclear material and facility stabilization or decommissioning projects at the Geothermal Test Facility. All waste management activities are conducted within the scope of the Environmental Restoration program. The Department of Energy, Office of Energy Efficiency is the landlord at the Geothermal Test Facility and is responsible for associated activities and costs.

FUTURE USE

When restoration activities are complete, the Department will turn the facility over to the Bureau of Land Management for unrestricted use. The Department assumes that this area will be reserved as a wildlife management area for several protected and endangered species. The Oakland Office has met with the Bureau of Land Management and the Regional Water Quality Control Board regarding restoration requirements. Current requirements, including a Waste Discharge Requirements Order, prescribe the removal of all brine pond sediment.

ENVIRONMENTAL RESTORATION

No active processes or experiments involving Department of Energy research are currently operating or planned at the Geothermal Test Facility. Sources of contamination are related to past operations at the site. Untreated brine extracted during geothermal exploration and brine blowdown water were stored in a holding pond at the facility. Storage of brine in the holding pond resulted in contamination of sediments with soluble salts and arsenic. Current estimates assume that no contamination is present beneath the brine pond liner. See the Site Map for the location of contamination.

In 1989, the Colorado River Basin Regional Water Quality Control Board issued a Waste Discharge Requirements Order. The Resource Conservation and Recovery Act requirements under Subtitle C are not applicable to the brine pond because it does not contain any hazardous waste. Therefore, the Regional Water Quality Control Board is the lead agency for the cleanup effort. Coordination will be required with the Bureau of Land Management because the Department uses the site under a Right of Way agreement. To terminate the Right of Way agreement, the Bureau of Land Management will have to accept and approve the restoration activities completed at the site.

In addition to the brine pond restoration activities, asbestos will be removed from structures onsite to allow the site landlord to demolish and remove them. Asbestos is fixed in the tiles, panels, and joints, and does not pose an immediate hazard. All asbestos waste will be disposed of at a commercial hazardous waste landfill permitted for such material. The Department does not expect any mixed waste to be generated from either the asbestos or brine pond restoration activities. A septic tank connected to the yellow laboratory building must be sampled to determine if it contains hazardous substances.

ASSESSMENT

A field investigation report on the brine holding pond was prepared in 1992 and a site characterization study of the balance of the site was completed in 1993. Assessment activities included grid sampling of the sediment in the brine pond and direct sampling of potential asbestos contaminated materials. Based on the results of the grid sampling, the Department determined that no Resource Conservation and Recovery Act waste was present in the brine pond. Contamination of the brine pond resulted from salts and minerals concentrated in sediment by evaporation.

Assessment activities have concluded that the most effective long-term solution for remediating the brine pond is to excavate the contents and dispose the material at an appropriate disposal facility. Decontamination activities will

generate two waste streams: nonaqueous soil/debris contaminated with arsenic, and nonaqueous, nonhazardous debris contaminated with salts and minerals.

The Department will not complete any further characterization work prior to initiating remedial action on the brine pond. The Regional Water Quality Control Board is discouraging any further characterization activity and is emphasizing the use of funds to remove the brine sludge from the pond. Data reported in the 1992 field investigation has been deemed acceptable. The Department is currently negotiating a cleanup schedule with the Water Board. Additional sampling will be required beneath the liner of the brine pond once restoration activities have been completed to verify the residual contamination levels. It is highly unlikely that brine pond contaminants have migrated past the pond liner because of the nature of the site and an annual precipitation rate of less than three inches.

In 1992, the Department conducted a visual site survey to identify locations of material suspected of containing asbestos. Nine of 18 samples collected from the suspected locations tested positive for asbestos. The Department collected samples from piping insulation, cooling tower millboard, floor tile and mastic, and various other locations throughout the facility.

Sampling will be required to investigate the contents of a septic tank system that is known to be connected to the yellow laboratory building. No as-built drawings exist that identify the location of the septic tank or piping. A work plan will be developed in FY 1999 to identify the location of the tank and piping and to determine the types of sampling that will be required. This project may be accelerated if funding is available. The projected timeframe is FY 1999 and this report assumes that the work plan and activities will be completed within that year.

REMEDIAL ACTION

A limited feasibility study was completed on the brine pond to evaluate different restoration options. This study has been forwarded to the Regional Water Quality Control Board and a cleanup alternative will be negotiated. This estimate assumes that the Department will excavate the brine pond and dispose of the debris at an offsite commercial disposal facility. Current estimates assume that contamination is contained within the 10-mil liner beneath the brine pond; however, samples have not been taken beneath the liner.

The Waste Discharge Requirements Order requires all brine pond sludge to be removed and disposed of at an offsite permitted facility. Other options included no action, covering the material with a soil cap, and covering the material with an engineered cap. After considering the requirements of the Water Board, the preferences of the Bureau, the long-term effectiveness of all the potential actions, and the cost and impact to human health and environment, it was determined that removal of the sludge presented the best alternative.

The volume of contaminated sediments to be removed from the brine pond is estimated at 9,175 cubic meters (12,019 cubic yards) of hazardous waste. Removal of the brine pond sludge sediment will require approximately 700 truck trailer trips between this site and the designated disposal site.

This report assumes that 40 cubic meters (54 cubic yards) of asbestos­containing materials will be removed and disposed offsite at an appropriate commercial disposal facility. Several areas containing potentially airborne asbestos were previously remediated in 1993. All loose asbestos was doubled bagged and disposed at a permitted offsite commercial disposal facility. A total of 1.1 cubic meters (1.5 cubic yards) of material was removed and included fibrous tar debris and insulation material. Asbestos contaminated locations remain where the asbestos was not loose and would not release fibers unless it was broken up. Materials that will require abatement because of asbestos content include a joint compound used around pipe joints and flanges, cooling tower millboard, and floor tile and mastic inside the yellow laboratory building. These areas will be abated in FY 1999.

The Department will sample the septic tank system to determine if any hazardous materials were disposed of in the system. Upon completion of sampling activities, the septic tank system will be excavated and disposed at a permitted offsite commercial facility. This report assumes that excavation and disposal of the septic tank will not generate any hazardous waste.

On the basis of previous sampling, the quantity of hazardous waste to be generated during environmental restoration activities will be minimal. This report assumes that it will be limited to equipment decontamination activities. Generated hazardous waste will be accumulated in accordance with generator requirements for nonpermitted facilities and will be treated and disposed at appropriate offsite commercial facilities.

Direct Program Management/Support

Because the Geothermal Test Facility is an inactive site, there are no current site management tasks other than planning for restoration efforts. When funding is available for restoration, program management will include typical management tasks such as strategic planning, liaison with regulatory agencies, scheduling, document preparation, budget control, and financial forecasting. Program support will include typical management tasks such as strategic planning, liaison with the Department and external regulatory agencies, scheduling, document preparation, budget control, and financial forecasting.

DESCRIPTION OF PERSONNEL

Current Composition/Future Full-Time Equivalent Needs

There are no Environmental Management employees onsite. A portion of a federal Full-Time Equivalent is allocated to manage facility activities. Because activities have not begun, and no contract has been awarded for restoration activities, no contractor personnel are currently working on this site. Site management structure and future personnel needs will be addressed in greater detail as the requirements are more fully identified. The table below represents the current Full-Time Equivalent required at the site.

*The projections for Full-Time Equivalent employees are based on FY 1996 planning baselines (see Reader's Guide).

Site Management Structure

The Oakland Operations Office is the field organization responsible for implementing Management Plans at the site. The facility landlord is the Office of Energy Efficiency, Golden Field Office which perform site management activities. The Oakland Office is managing office responsible for environmental activities. A contract for site restoration activities has not been awarded to date, but a task order type contract is in the final stages of procurement.

FUNDING ESTIMATE

The following table presents estimated funding information for the Geothermal Test Facility.

COMPARISON WITH PREVIOUS ESTIMATE

Life-cycle costs at the Geothermal Test Facility decreased from approximately $7 million in the FY 1995 estimate to $5 million in the FY 1996 estimate. This reduction is due to the availability of more mature analytical data.