In 2010, USAID carried out an Environmental Assessment that analyzed conditions at Danang Airport and evaluated a number of possible dioxin remediation technologies. Thermal desorption treatment was determined to be the most effective and scientifically proven method for destroying dioxin and to have the lowest potential impact on human health and the environment given the specific conditions of the site.

The technology is an innovative dioxin destruction technology that uses conductive heating and vacuum extraction to remediate soil and sediment contaminated with dioxins. The excavated soil and sediment is placed into a completely enclosed above-ground pile structure. Heating rods operating at temperatures of approximately 750 to 800 degrees Celsius (°C) (1400 to 1500 degrees Fahrenheit [°F]) raise the temperature of the entire pile to at least 335°C (635°F).  At that temperature, the molecular bonds holding the dioxin compound together break, causing the dioxin compound to decompose into other, harmless substances, primarily CO2, H2O and Cl2.

The contaminated soil and sediment will be placed into the pile structure in two phases, and heated at this high temperature for several months to destroy the dioxin. After testing confirms that the soil is clean, the phase 1 clean soil and sediment will be removed and the phase 2 contaminated soil and sediment will be placed in the pile structure to undergo the same heating process.

It is expected that over 95 percent of the dioxin will be destroyed through the thermal desorption heating process. Any dioxin that vaporizes will be vacuumed out and captured in a secondary treatment system for liquids and vapors extracted from the pile. The secondary treatment system will ensure that no dioxin or other contaminants are released into the environment.

See also:

• Progress Reports for the Environmental Remediation Project at Danang Airport
• Project Timeline
• Remediation Areas
• How Health and Safety Concerns Have Been Addressed
• Frequently Asked Questions
• Key Facts about the Environmental Remediation Project in Danang