You’ve gained an overview of the underground contaminants at your site, and you’ve decided they have to go. What should you consider when choosing the best method for your cleanup operation?

There are three important factors: the depth of the contamination, soil type and nearby installations and buildings. These will be clear from the soil analysis results and the 3D model of the contaminated area. 

Dig it out

If the contamination is just two to four meters below the surface and above the groundwater table, the cheapest and fastest option is almost always excavation. The soil is then simply removed and disposed of at a regulated landfill site or taken for treatment.

Biological removal 

But, if the contaminants are located deeper or are detected in porous soil types containing groundwater that can transport substances further afield, in-situ remediation is a better choice. The same applies if the site is an active filling station, which will have to be closed down while excavation work takes place – bringing loss of income. In-situ remediation involves treating the site with a biological product that eliminates contaminants over a period of months or a few years. Treatment takes place by injection at strategically placed boreholes on the site. When this type of cleanup operation is used, activities on the site can continue as normal with only minimal disturbance. At Ejlskov we use patented Trap & Treat^® technology for this purpose.

Other methods 

Other methods of in-situ remediation include pump and treat, soil vapour extraction and air sparging. All work by slowly removing the contaminants bound in the soil. Due to a cleanup timescale of 15 to 30 years and high running costs, these are options we rarely recommend.

Interested in hearing more about the most cost-efficient cleanup choice for your site? You`re welcome to contact me.