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Examples of Groundwater Cleanup Approaches
E-mail note from Robert Springer, Director of the Office of Solid Waste (name changed to Office of Resource Conservation and Recovery on January 18, 2009) sent to Regional EPA RCRA Senior Policy Advisors (June 16, 2003). The intent of this note is to share many examples of groundwater cleanup approaches being implemented around the country that are consistent with the protective yet flexible policy framework provided in the Handbook of Groundwater Protection and Cleanup Policies for RCRA Corrective Action.
Groundwater Example Note (PDF) (1 pg, 9K, About PDF)
If you would like the Agency to consider posting your RCRA-related groundwater cleanup example on this web site, please submit the following information to Dave Hockey (hockey.david@epa.gov):
- a 250-word or less description, with web link for more information if available;
- contact information (name, phone # and email address) for the individual submitting the example as well as for the EPA or State official most knowledgeable about the example;
- and, the category under which you believe the example would fit best. The individual submitting the example will be notified prior to posting.
In addition, below are more examples:
- Categories of Examples
- Facilities Sometimes Need to Take Extensive Actions to Ensure Protection
- Source Control Can Often Lead to Cost-effective Long-term Solutions
- Results-based Milestones Can Help Focus Efforts and Demonstrate Progress
- Groundwater Cleanups and Land Revitalization
- Cleanup Goals Acknowledge Technical Limitations in Addition to Groundwater Use
- Groundwater Quality and Use Can Be Significant Factors in Cleanup Decisions
- States Managing Contaminated Groundwater in Defined "Zones" and "Areas"
Categories of Examples
- Facilities sometimes need to take extensive actions
to ensure protection
- Source control can often lead to cost-effective
long-term solutions
- Results-based milestones can help focus efforts
and demonstrate progress
- Groundwater cleanups and land revitalization
- Cleanup goals acknowledge technical limitations in
addition to groundwater use
- Groundwater quality and use can be significant
factors in cleanup decisions
Facilities Sometimes Need to Take Extensive Actions to Ensure Protection
- At Reese Air Force base in northwest Texas, the Base Realignment and
Closure (BRAC) Cleanup Team, consisting of EPA, DOD and Texas representatives,
addressed extensive groundwater contamination present in an aquifer
that is used as a drinking water source. The major groundwater problems
included two TCE plumes and a Benzene plume. One of the TCE plumes extended
off-site approximately 2.5 miles and impacted numerous drinking water
wells. The cleanup team's approach involved open communications between
team members as well as with interested members of the public. The complex
groundwater remedy is multi-faceted. In particular, the remedy involves
an on- and off-site groundwater pump-and-treat system with 50 extraction
and injection wells and over 10 miles of piping. The reinjection of
the treated groundwater is an important aspect of the remedy to maintain
groundwater levels in the aquifer. Another critical aspect of the remedy
to help ensure human health protection included sampling of over 500
residential wells within 45 days, providing alternative water supply
or in-home treatment systems to affected homes, and real estate negotiations
for over 200 rights of entry and 19 easement purchases. More information.
- Texaco installed a 3,400-foot "sealed-joint" sheet-pile barrier wall along the North Platte River to contain contaminated groundwater and free product at its refinery in Casper, Wyoming. This barrier wall, which is one of the largest in the world, was essential to achieving the Migration of Contaminated Groundwater Under Control environmental indicator, and will be an important component of Texaco's long-term cleanup efforts. Additional information regarding this cleanup (PDF) (15 pp, 1.1MB, About PDF)
Source Control Can Often Lead to Cost-effective Long-term Solutions
- The groundwater cleanup at the Kings Bay Submarine Base in Kings
Bay, Georgia combined innovative source treatment with monitored natural
attenuation. The groundwater problem at the facility originated from
an old 35-acre municipal landfill that the facility acquired with land
it purchased from the county. As an outcome of the partnering efforts
by the State, United States Geologic Survey, and the Navy as well as
the Navy's contractor, the selected remedy involved aggressive source
treatment (injection of hydrogen peroxide - Fenton's Reagant - into
a portion of the landfill found to contain dry cleaning wastes) and
monitored natural attenuation for the dissolved plume. Levels of total
chlorinated hydrocarbons in the most-contaminated area have been reduced
from nearly 200,000 ppb in 1999 to 120 ppb in 2002. Furthermore, in
the three years since source treatment began, the off-site plume is
currently below drinking water standards and the on-site plume is approaching
those same cleanup levels.
- At a DuPont facility in Kinston, North Carolina, a TCE plume was being treated and contained by a pump-and-treat system for approximately 8 years as an interim measure. Because the system was costly and ineffective at removing the contamination, DuPont decided to review other potential technologies for containment and treatment. In 1999, DuPont installed a permeable treatment wall within the plume, and at the same time attacked the source by using an innovative technology that combines contaminant stabilization with destruction. Since the source area was relatively small (i.e., less than one acre) and well defined, the treatment technology chosen was more cost-effective than the pump-and-treat system and provided the added benefit of reducing long-term liability. Current data indicate: approximately 90% of source area soil sampling points were cleaned up to below detection limits for TCE and daughter products; the treatment wall is degrading TCE that is migrating downgradient; and, plume concentrations between the source area and the treatment wall are decreasing.
Results-based Milestones Can Help Focus Efforts and Demonstrate Progress
- The groundwater cleanup at the ESAB Welding Products facility in South Carolina is an example of establishing "Intermediate Performance Goals"as helpful milestones between short-term protection and final cleanup goals. In response to concerns expressed from an adjacent land owner, the facility established the milestone of cleaning up the contaminated groundwater that had extended beyond ESAB property. Four years after the installation of the pump and treat system, the State approved the shutting off and abandonment of the off-site extraction well because no off-site contamination was detected above levels of concern.
Groundwater Cleanups and Land Revitalization
- The cleanup of the Sparton Technology, Inc. facility in Albuquerque, New Mexico, was designed to be compatible with property reuse. The groundwater remedy involved a containment and restoration system that addressed the entire contaminant plume, along with a soil vapor extraction system to further reduce the remaining source material beneath the facility, and indoor air sampling at a new automobile dealership to ensure that the contaminated groundwater did not create unacceptable exposure. Furthermore, the groundwater collection, treatment and discharge (several infiltration basins) systems were all designed to blend in with the revitalized property (i.e., the new auto dealership) and the surrounding neighborhood. More information.
Cleanup Goals Acknowledge Technical Limitations in Addition to Groundwater Use
- At the Seagate Technology facility in Nebraska (a State not authorized
for corrective action), EPA concluded that because of low yield, the
shallow formation was not a reasonably expected source of drinking water.
In addition to the groundwater use determination, EPA recognized the
limitations of cleanup technologies associated with removing non-aqueous
phase liquid contamination in this low permeability formation. Therefore,
EPA selected a remedy designed to protect the underlying formation that
is used as a regional source of drinking water.
- In Region III, EPA collaborated with Pennsylvania's Act 2 Land Recycling Program in achieving cleanup goals at the PECO facility in Chester. This facility was the former location of a resin manufacturing plant and hazardous waste recycler. The groundwater is contaminated by organic compounds and LNAPL, some of which discharged to adjacent surface water. The final remedy recognizes the technical limitations associated with groundwater restoration and establishes final cleanup goals for groundwater based on protection of surface water to which the plume discharges. The City of Chester code restricts people from using the groundwater as a source of drinking water. This use restriction is an important component of institutional controls to prevent exposure to groundwater contamination for the final remedy. More information about the PECO facility (PDF) (3 pp, 12K, About PDF)
Groundwater Quality and Use Can Be Significant Factors in Cleanup Decisions
- In Connecticut – a State not yet authorized for corrective action
– EPA generally relies on the State's groundwater classification
system in setting cleanup levels. For example, groundwater beneath the
Dow Chemical facility in Ledyard is classified under the State system
as not being a drinking water source. Therefore, after documenting that
there were no existing drinking water supply wells, EPA established
cleanup levels and a point of compliance for this facility based on
protection of the surface water body into which the groundwater discharges.
For more information, see Connecticut's classification system.
- While Georgia generally defines its groundwaters as a potential source
of drinking water, the State also allows the use of site-specific factors
to establish alternate groundwater cleanup objectives. For example,
the final remedy at the Atlantic Steel facility in downtown Atlanta
involved containing contaminated groundwater rather than restoring the
groundwater to drinking water levels. Some of the factors Georgia considered
in approving the remedy included the lack of anticipated use of the
groundwater beneath the facility, the reliability of containment, and
the ability of the remedy to ensure long-term protection.
- Michigan generally assumes as a starting point that all groundwater
is a potential source of drinking water. However, the State allows a
facility owner or operator to petition it either to grant a waiver of
the presumed drinking water classification or to recognize that certain
groundwater beneath a particular site is not in an aquifer; the result
of either the waiver or a Groundwater Not in An Aquifer determination
would be that the groundwater ingestion exposure pathway is not considered
in establishing groundwater cleanup goals. For example, at the Selfridge
Air National Guard Base in Mt. Clemens, Michigan granted a petition
that the groundwater at a portion of the site is not in an aquifer and
therefore the ingestion pathway cleanup criteria do not apply in establishing
cleanup levels.
- The cleanup of the GM facility in Moraine, Ohio illustrates recognition
of different groundwater uses and associated exposure scenarios. In
this situation, the shallow groundwater is not used as a drinking water
supply due to naturally high iron and calcium carbonate, but the local
county recognizes the lower aquifer as a backup water supply. As such,
the groundwater cleanup objective for shallow groundwater is based on
protection of the lower aquifer. The remedy for the shallow groundwater
involves aggressive source area treatment and halting further lateral
migration of the plume by three permeable treatment walls. An important
element of this remedy is the long-term monitoring of groundwater conditions
and implementation of institutional controls to prevent against unacceptable
exposures
- The Washington State Department of Ecology Model Toxics Control Act
(MTCA) generally identifies drinking water criteria as default standards
for groundwater cleanups. Nevertheless, the regulations also include
criteria that can be used to apply alternate cleanup standards for certain
groundwaters. For example, the MTCA program includes a regulatory process
that allows for the highest beneficial use of groundwater at specific
sites, including some along the Duwamish Industrial Corridor, to be
identified as "discharge to surface water." These negotiated
site-specific determinations allow for groundwater cleanup standards
to be established based on protection of surface water into which the
groundwater is discharging. This regulatory process, combined with site-specific
groundwater use designations, provides a consistent framework for setting
groundwater cleanup goals that can enhance the use and re-use of industrial
properties in the corridor. More information about the MTCA program
and regulatory provisions concerning groundwater use determinations (PDF) (300 pp, 2,5MB, About PDF)
- see section 720 regarding groundwater cleanup.
States Managing Contaminated Groundwater in Defined "Zones" and "Areas"
- A number of States are using various approaches to acknowledge the presence of contamination above cleanup goals in a way that helps ensure protection while supporting longer-term cleanup actions such as monitored natural attenuation. An example includes: