Thermal desorption not only cleans the soils, it eliminates the problem of hydrocarbon contamination under all conditions in a timely manner. The process will clean soils to meet or exceed the most restrictive regulatory guidelines.
Some of the typical contaminates that are routinely encountered are:
- Aviation Gas
- Natural Gas Condensate
- Hydraulic Oil and Gear Oil
- Used Oil.
After excavation, the contaminated soil is placed in a hopper and fed to a rotary dryer unit where it is heated to temperatures that sufficiently volatize the petroleum hydrocarbons. The exhaust gases from the dryer system are then carried through a dust collection system called a “baghouse”. Only the gases are subsequently carried to the thermal oxidizer unit.
In order to ensure total oxidation of the contaminants in the thermal oxidizer, instrumentation measures the levels of oxygen, temperature, and any carbon monoxide in the outlet gas stream. Sampling and analyses of the clean soils exiting the system are conducted to verify remediation, prior to recycling.
Why Thermal Desorption?
Thermal desorption eliminates petroleum contamination every time and in a timely manner while other technologies do not. This is all the more evident in Alaska were natural environmental conditions directly inhibit the success rate of most other technologies. With Alaska’s reduced heating degree days, permafrost and arctic conditions, intense moisture, and shorted field seasons it is our opinion that thermal desorption is the only guaranteed approach.
The recycling and reuse of the soil after thermal desorption prevents the consumption of valuable landfill space. Although landfilling is a legal option, many companies today discourage the use of landfills in their environmental stewardship policies whenever possible. Furthermore, the use of clean burning natural gas and the prevention of uncombusted volatile gases exiting the system appeal to the Green and Sustainable Remediation (GSR) practices that are encouraged by our customers.