In the broadest use of term, in-situ chemical oxidation (ISCO) refers to the use of chemical oxidation (addition of oxygens) for the in place remediation of contaminants. In practice, the term is often used to describe process of injection or direct mixing of reactive chemical oxidants with the soil and groundwater for the purpose of destroying (oxidizing) chemical contaminants in place. Within the context of soil mixing, this term refers to the use of chemical oxidants delivered and mixed with the soil, via soil mixing, for the purposes of in place treatment. The most common type of soil mixing used for ISCO is large diameter single auger soil mixing, but the technique can be accomplished using excavator buckets and rotary tools too. Soil mixing offers numerous technical advantages over alternative oxidant delivery methods, with the largest advantage being that intimate contact between the oxidant and contaminants in guaranteed with soil mixing, independent of soil lithology. Other methods like direct injection are not effective in certain soil types and, even in soil types that are conducive to direct injection, the injection program can have variable effectiveness in achieving oxidant / contaminant contact.
Geo-Solutions has completed a number of soil mixing projects for accomplishing in-situ chemical oxidation objectives. Some of the more common oxidant reagents that Geo-Solutions has used include potassium permanaganate, calcium peroxide, hydrogen peroxide, and sodium persulfate.
