Construction of In-Pile Thermal Desorption structure and Excavation of contaminated materials in Danang Military Airbase

Project:	Environmental Remediation of Dioxin contamination at Danang Airport
Work item:	Construction of In-Pile Thermal Desorption (IPTD) structure and Excavation of contaminated materials.
Location:	Danang Military Airbase, Danang City
Implementing Partner:	Air Force Air Defense Command (AFADC)
Funding Agency:	United States Agency for International Development (USAID)
Implementing duration:	From 8/2012 to 11/2018

Project Summary

After ground breaking ceremony in August 2012, the project started with its first component which was to build a structure for thermal desorption application (IPTD). The project continued with excavation of contaminated soil and sediment and hauling to IPTD for treatment. The IPTD filled with contaminated material was then capped with insulating concrete and other layers as per designed. The final step of project operation was to remove all treated material from IPTD and demolish entire IPTD structure, returning the site back to the airbase.

The Project successfully treated over 94,000m3 of contaminated soil and sediment (from dioxin concentration of input level of above 1,200ppt to below 150ppt); securely landfilled over 68,000m3 of contaminated soil with concentration of below 1,000ppt.

In this project, Tri Viet in association with its partner provided the following services to the US main contractors:

Construction of the IPTD structure with dimensions of 70m(W) x 105m(L) x 7m (H). The bottom, the wall and also the cap of the IPTD structure were constructed with different layers to ensure the thermal insulation as designed. The insulation layers include 60cm thickness of light weight insulation concrete. On the wall, there were other layers such as 1mm thickness HDPE, inter-locking metal panels. The entire IPTD structure was surrounded by over 28,000 Concrete Mason Unit (CMU) blocks of the dimension 60cm x 60cm x 132cm.
Excavation, hauling and compaction contaminated soil and sediment: over 120,000m3 of contaminated materials were excavated following the design. Over 2/3 of this excavation volume was treated in IPTD and the rest was landfilled at a location to the southwest of the airbase.
Support installation/ and removal of the heater cans
Support the confirmation sampling of the in-pile soil during/post treatment

By the end of the project, a total of 32.4 hectares of “clean” land was handed over back to the airbase for expansion of Danang International Airport and for other land-use purpose. The project helps minimize the risk of environmental and people exposure to dioxin and in the meantime, it helps “remove Danang out of the list of dioxin contaminated hotspots in Vietnam”. This project was one of the largest and most complicated in its kind with an initial estimation based on preliminary design. The actual volume of soil and sediment requiring removal (excavation) and treatment was higher than original estimate, from 72,900m3 to 162,500m3.