For environmental remediation of hazardous material, conventional excavation equipment can be slow and harmful. CEG’s supersonic air jet and pneumatic vacuum transport technology makes environmental site remediation easy, fast, non-damaging, and:

• Is able to uncover buried waste containers without fear of puncture
• Contains the soil material as it is excavated to prevent air borne contamination
• Can be made to continuously separate the spoil in stages so that various elements can be selectively separated
• Can be combined with other processes to treat the spoil or waste in a continuous process
• Can achieve excavation rates comparable with much larger pieces of equipment
• May be combined with robot manipulators to dig in ways that conventional backhoes or excavators cannot
• Removes material in carefully controlled layers
• May be remotely controlled to remove the operator from the immediate vicinity of the contamination

Savannah River Demo

In the late 90's, CEG was asked by Savannah River DOE Site to perform a test to see if CEG's Soft Trencher technology could excavate buried drums. A box was constructed that contained a number of 55 gallon drum that were covered with compacted dirt. The CEG Soft Trencher was successful in uncovering the drum tops without damaging them and was much faster than digging by hand.

To watch a video from the excavation click here

Remote Air-Vacuum Excavator for DOE Sites

The Department of Energy manages about 98 million cubic yards of soil contaminated mainly from nuclear weapons production at 64 environmental sites in 25 states. Hanford, Washington and Savannah River, South Carolina have the largest amounts of contaminated media. In Solicitation Number DE-RA26-03NT41755, DOE stated that, “ Excavation technologies for application at actual TRU waste burial grounds have not been successfully demonstrated.” It goes on further to state, “Current technologies such as the Guzzler vacuum / Soft Trencher (CEG Inc.), which can remove soil without disturbing large debris, and the Sonsub soil skimmer (Sonsub) which can remove small layers of soil in a controlled manner, require adaptation for highly radioactive environments for worker and environmental radiation control and decontamination.”

Located in southeastern Washington State, the Department of Energy Hanford 618-10 and 618-11 burial grounds contain low to high-level activity waste from pre-1970 defense production of plutonium. At these sites a total of about 144 vertical pipe units (VPUs) were used for storage of remotely deposited intermediate and high-level radioactive waste. Each vertical pipe unit consisted of five 3-foot high by 22-inch diameter open-ended drums welded end to end. Records are unclear as to whether the pipe units were capped on the bottom, sitting on concrete foundations, or open to the soil. When at capacity, the pipe units were backfilled and topped with concrete. About 4 feet of soil was placed over the site in 1983.

An initial concept for a remotely operated, air-vacuum excavator is shown below for working next to a VPU. The tracked unit would use wide rubber tracks for all terrain operation with low ground pressure for minimum damage to buried waste containers. A light weight, telescoping, composite material boom would extend down from the digging unit. The straight-thru design of the digging boom eliminates the common clogging problem with vacuum systems that use flexible hose. This is very important for a remote system where clogs would require intervention by personnel into a hazardous situation. Multiple supersonic air jets on the end of the boom in the rotary digging head loosen the soil that is then sucked into the boom by the vacuum. Since the intake volume of vacuum airflow is an order of magnitude greater than the airflow from the supersonic jets, dust and possible contamination are taken into the system rather than discharged to atmosphere. Ideally the boom would be also able to dig at an angle to the ground surface to reach spots on the VPUs for detail work. Tables below give some initial specifications for the unit.

Remotely operated air-vacuum tracked unit for work around VPUs or caissons.

Equipment Skid Specifications

Digging Boom Specifications

Linking Legacies. 1997. U.S. Department of Energy. Office of Environmental Management. DOE/EM-0319.

DOE Solicitation Number DE-RA26-03NT41755. In-Situ TRU Delineation and Waste Removal of Radioactive Waste at Hanford 618-10 and 618-11 Burial Grounds. 2003.