ARCTIC FOUNDATIONS INC.

(Cryogenic Barrier)

TECHNOLOGY DESCRIPTION:

Long-term containment and immobilization of hazardous wastes using ground-freezing technology is a relatively new field, even though ground-freezing has been used as a temporary construction aid for several years. Ground-freezing is ideally suited to control waterborne pollutants, since changing water from a liquid to a solid has an obvious immobilizing effect. The challenge for conventional ground-freezing technologies is to be technically and economically viable in the long-term. Arctic Foundations, Inc. (AFI), has developed a ground-freezing technology that has been used as a permanent, long-term solution for containing and immobilizing hazardous wastes.

Buried hazardous waste may be totally confined by surrounding it with a frozen barrier. A frozen barrier is created by reducing the ground temperature around the waste to the correct freezing temperature and subsequently freezing the intervening waste. Artificial injection of water is usually unnecessary since moisture is present in sufficient quantities in most soils. The ground-freezing process is naturally suited to controlling hazardous waste because in-ground moisture is transformed from serving as a potential waste mobilizing agent to serving as a protective agent.

A typical containment system consists of multiple thermoprobes, and active (powered) condenser, an interconnecting piping system, two-phase working fluid, and a control system. The thermoprobes (AFI's heat removal devices) and piping are inserted into the soil on all sides and underneath the waste. Two-phase working fluid circulates through the piping and reduces the temperature of the surrounding soil, creating a frozen barrier around the waste. The thermoprobes may be installed in any position and spacing to create a frozen barrier wall of almost any required shape and size. The selection of working fluids depends on the specific waste application, site conditions, and desired soil temperatures, and may consist of freon, butane, propane, carbon dioxide, or ammonia.

WASTE APPLICABILITY:

The cryogenic barrier can provide subsurface containment for a variety of sites and wastes, including the following: underground storage tanks; nuclear waste sites; plume control; burial trenches, pits, and ponds; in situ waste treatment areas; chemically contaminated sites; and spent fuel storage ponds.  The barrier is adaptable to any geometry; drilling technology presents the only constraint.

STATUS:

The system was accepted in the SITE Demonstration Program in 1996. The demonstration will evaluate the barrier's ability to contain radionuclides from the Oak Ridge National Laboratory (ORNL) Waste Area Grouping 9 Homogeneous Reactor Experiment (HRE) pond. Hydrological data indicate that radioactive contaminants are being released from the HRE pond to the groundwater and surface water.

FOR FURTHER INFORMATION:

EPA PROJECT MANAGER:
Steven Rock
U.S. EPA
National Risk Management Research
Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7149
Fax: 513-569-7105

TECHNOLOGY DEVELOPER CONTACT:
Ed Yarmak
Arctic Foundations Inc.
5621 Arctic Blvd.
Anchorage, AK 99518
907-562-2741
Fax: 907-562-0153