Thermal remediation of a dioxin megasite in Vietnam
Jan Haemers, Mael Makoudi, Aline Jordens, Aurélien Vandekerckhove (Haemers Technologies, Brussels, Belgium)
More than forty years after the Vietnam War, several former airbases remain heavily contaminated by dioxins associated with the storage and handling of Agent Orange. These sites represent some of the most challenging contaminated megasites worldwide due to the toxicity of the pollutants, the large volumes of impacted soils, and the complexity of managing remediation activities within active or sensitive environments.
This paper presents the application of ex-situ thermal desorption (ESTD) for the treatment of dioxincontaminated soils at Vietnamese airbases. The technology relies on conductive heating of excavated soils to approximately 335 °C. At this temperature, dioxins volatilise and are extracted from the soil mass. The contaminated vapours are then treated in a dedicated vapour treatment unit equipped with a thermal oxidizer operating above 1100 °C, ensuring the destruction of the contaminants and preventing atmospheric release.
A pilot treatment campaign carried out at Biên Hòa airbase confirmed the effectiveness of the approach. Soils initially containing more than 11,400 ppt TEQ of dioxins were successfully treated to concentrations below remediation targets, with destruction efficiencies exceeding 99 %. Monitoring performed during the operation confirmed compliant air emissions and no measurable impact on ambient air quality.
Following this pilot phase, preparations are underway to implement the technology at a larger scale at the Phu Cat site. The project involves a preparatory phase covering engineering design, permitting, equipment mobilisation and local capacity building prior to treatment operations.
This case study provides practical insights into the use of thermal technologies for large-scale remediation of soils contaminated by persistent organic pollutants. It also highlights some of the technical and operational considerations associated with implementing remediation solutions at megasites, where treatment performance, environmental safety and long-term land management objectives must be addressed simultaneously.