Hot Gas Decontamination - ex situ
Hot gas decontamination involves raising the temperature of a contaminated material to 260 °C (500 °F) by exposing it to hot gases (e.g. propane or natural gas) for a specified period of time. The contaminant(s) are thermally decomposed or volatilized. The gas effluent from the material is extracted and treated in a system that destroys all volatilized contaminants. This technology is specifically applied to the remediation of materials contaminated with explosives such as demilitarized mines (i.e. after removal of explosives), shells, or soil from battlefields and training grounds. The hot gas decontamination treatment is also applicable to the remediation of buildings or structures associated with munitions plants, arsenals and depots involved in the manufacture, processing, loading, and storage of pyrotechnics, explosives and propellants.
A hot-gas system designed by the U.S. Army Environmental Center (USAEC) includes a hot-gas furnace, ducts and fans, a control system and a thermal oxidizer (afterburner). Treatment of contaminated gas emissions occurs in the afterburner, which has a continuous emission monitoring system to control the concentration(s) of contaminant(s) in the exhaust air before releasing it into the atmosphere. The furnace design must take into consideration possible explosions from improperly demilitarized mines or shells.
- 4.21 Hot Gas Decontamination - FRTR Remediation Technologies Screening Matrix and Reference Guide, Version 4.0
- Hot Gas Decontamination - Techtree - Center for Public Environmental Oversight (CPEO)
- Contaminant concentrations Footnotes1
- Soil granulometry
- Contaminant physical characteristics Footnotes2
- Gas permeability trials
- Evaluation of the radius of influence
- Air flow rate
- Evaluation of operating pressure/vacuum
- Hot gas decontamination is specifically used for treating residual explosives contamination, such as TNT, royal demolition explosive (RDX), trinitrophenyl-N-methylnitramine (Tetryl), Ammonium Picrate (Yellow D), Smokeless Powder and Mustard (H or HD);
- Operating conditions are site-specific;
- The contaminant(s) is completely destroyed during treatment.
- In situ
- Ex situ
- Dissolved contamination
- Free Phase
- Residual contamination
- < 1 year
- 1 to 3 years
- 3 to 5 years
- > 5 years
- The largest concern is atmospheric emissions from the afterburner;
- If chlorinated compounds are present, formation of dioxins and furans are of concern.
- The cost of this method is higher when compared to other types of explosive remediation treatments such as open pit burning;
- The rate at which equipment or material can be decontaminated is slower when compared to other types of explosive remediation treatments such as open pit burning;
- The hot gas furnace chamber design must take into consideration possible explosions from improperly demilitarized mines or shells.
- Incineration of the gas emissions.
- Collection and treatment of gas emissions;
- Because there is a variety of materials being volatized, thorough analysis and continuous monitoring of emissions are recommended.
- Low-Cost Hot Gas Decontamination of Explosives-Contaminated Firing Range Scrap - Enabling technology MR-200032 - SERDP-ESTCP organisation - USA
- Federal Remediation Technologies Roundtable (FRTR). 2002. Remediation Technology Matrix and Reference Guide, Version 4.0. U.S.A.
- Center for Public Environment Oversight (CPEO). 2002. Techtree: Hot Gas Decontamination. U.S.A.
- U.S. Army Environmental Command. 2006. Restoration Technology: Hot Gas Decontamination. U.S.A. (Document link no longer available)
Recommended Analyses for Detailed Characterization
Recommended Trials for Detailed Characterization
State of Technology
| Aliphatic chlorinated hydrocarbons |
Monocyclic aromatic hydrocarbons
| Non metalic inorganic compounds |
Policyclic aromatic hydrocarbons
Secondary By-products and/or Metabolites
Limitations of the Technology
Complementary Technologies that Improve Treatment Effectiveness
Required Secondary Treatments
Application examples are available at this address:
This process is between the pilot scale and field demonstration stages. The United States Army Environmental Center sponsored several demonstrations showing that 99.9% decontamination of structural components is possible. Items decontaminated for 6 hours at a minimum temperature of 260 °C (500 °F) were found to be safe for public release as scrap.
Josée Thibodeau, M.Sc
National Research Council
Latest update provided by:
Martin Désilets, B.Sc.
National Research Council
- Date modified