Thermal soil remediation technology using activated carbon for creosote removal
What is creosote?
Creosote has been widely used for the treatment of wooden railroad ties and wooden telephone poles to prevent rot. In the past, when there was less environmental awareness, creosotes often contaminated the soil in the wood treatment facilities. Creosotes are a variety of products that are mixtures of many organic chemicals, such as polycyclic aromatic hydrocarbons, phenol, cresols, etc. (See table 1). They are nowadays almost no longer used as a wood preservative because better and safer treatments are now available.
|Aromatic hydrocarbons||Tar acids / phenolics|
|2-Methylnaphthalene||Tar bases / nitrogen-containing heterocycles|
|Benzopyrene||Oxygen-containing heterocycles / furans|
Table 1: some coal tar creosotes chemicals
Soil remediation process: creosote removal and on-site air/water purification
The complete soil remediation process consists of two phases: the actual removal of the creosote (through ET-DSP) and the purification of air/water extracted from the soil (using a mobile purification system
Creosote removal: Electro-Thermal Dynamic Stripping Process (ET-DSP™)
At an old creosote impregnation site of the Belgian RTT (Regie voor Telegraaf en Telefoon), the predecessor of the Belgian telephone company, there is a historical creosote contamination that is being removed using an in-situ thermal remediation technology. This patented technology is specially developed for cleaning up contaminated sites and is called "Electro-Thermal Dynamic Stripping Process" (ET-DSP™). ET-DSP™ uses electrical power to heat the subsurface of the contaminated soil with electrodes. The electrodes are placed at various depths and locations on the contaminated site and the electrical current to each electrode is controlled continuously by computer, resulting in uniform heating of the target contamination zone. In situ thermal remediation site in Belgium (Picture taken by Euremtech BVBA)
On-site air/water purification using activated carbon
The air/water is then extracted and treated with DESOTEC’s activated carbon technologies like the AIRCON® and MOBICON® mobile purification systems. The process is summarised as follows:
Soil remediation process: ET-DSP™ and mobile air/water purification
AIRCON® HC for creosote removal (picture taken by Euremtech BVBA) The on-site purification solutions DESOTEC provided:
- Heavily loaded extraction air treatment Flow: 765 Nm3/h Temperature: <25°C Skid mounted manifold 2 x AIRCON® HC AIRPEL® 20
- Stripping air treatment Flow: 5 m3/h Temperature: <35°C 2 x AIRCON® 2000 AIRPEL® 20
- Creosote removal from water Flow:4 m3/h Temperature: <30°C 2 x MOBICON® 2000 ORGANOSORB® 20-AA
During a six-month operation, more than 30,000 kg of creosote will be extracted and sent to an authorised treatment facility and will be treated in a safe and environmental manner. Curious about DESOTEC’s total purification solutions and other international business services? Feel free to contact us at any time, we’re at your service!
At DESOTEC’s facilities, all used carbon is analysed so the right measures can be taken for handling and removing the saturated carbon out of the mobile filters. All molecules that were adsorbed on the activated carbon at the customers’ site, are desorbed inside DESOTEC’s reactivation furnaces. These contaminants are then fully destroyed, in accordance with National and European legislation, by an incineration and neutralisation setup. The entire installation and it's emissions are under continuous on-line monitoring, which guarantees that only harmless water vapour is seen exiting the chimney.