PBIE Article – Intermediate Progress Report
During the US-Vietnam War, millions of liters of herbicides were dropped over Vietnam: The Rainbow agents. Those Rainbow Agents were sprayed throughout the Operation Ranch Hand to clear thick jungle, by defoliating crops and forest.
Among these Rainbow agents, Agent Orange was proven to cause severe health issues, including birth defects, neurological problems and cancers.
Indeed, Agent Orange contained dioxins which are highly toxic environmental persistent organic pollutants. More than four decades after the Vietnam War ended (in 1975), the stability and bioaccumulation of dioxins still affect the inhabitants. Measures had to be taken to improve living conditions for residents, starting with the remediation of dioxin contaminated soil.
A pilot of Ex Situ Thermal Desorption (ESTD), in partial combination with soil washing, is conducted by Haemers Technologies © at Biên Hòa Airbase to remediate dioxin contaminated soil.
Objective
The key objective of the trial treatment is to demonstrate the effectiveness of The Smart BurnersTM treatment technology and design in order to meet the site-specific dioxins target levels.
Therefore, Haemers Technologies has designed a thermal treatment pilot plant composed of two main units:
- The soil pile (ESTD) to be heated up to 330°C in order to desorb and vaporize the dioxins
- The vapour treatment unit where dioxins are destroyed in a Thermal Oxidizer
ESTD design
The Ex-Situ Thermal Desorption (ESTD) is conducted in a landfill area, where contaminated soils have been stored and restrained over the years. This pilot-pile is composed of various contaminated materials: 60% are contaminated soils directly extracted from the polluted area, 20% are contaminated sludges and another 20% are contaminated residues from a soil washing facility.
Vaport treatment
The purpose of the Vapor Treatment Unit is to destroy the contaminated vapors produced by heating the soil. All that while remaining within the strictest legal emission standards. For this pilot project, Haemers Technologies has designed a Thermal Oxidizer to incinerate and destroy all vapors and condensates, i.e. all dioxins. The Thermal Oxidizer operates at a minimum temperature of 1200°C, with a residence time in excess of 2 seconds. This guarantees full destruction of all dioxins and furans, resulting in a zero-waste process.
Project stage
Treatment has began in February 2022 and is currently underway. The results obtained so far are very promising!
The average temperature in the ESTD after 22 days of heating is 253°C. We estimate the end of the treatment by early/mid-March.
The emissions collected at the outlet of our clean-up installation are within the strictest Vietnam, European and US emission standards, validating our vapor treatment system.
We look forward to share with you all our results, once our pilot project will be completed!