In-Situ Solidification (ISS)

ISS is the process of blending treatment reagents into impacted media to impart physical and/or chemical changes that most often result in reduced mobility and leachability of constituents of concern (COCs), increased soil strength, and reduced permeability of the soil matrix. While grouped together in name, In-Situ Solidification binds the contaminants in a solid block to trap it in place, whereas In-Situ Stabilization uses chemical reactions that makes contaminants less likely to be leached into the environment.

In-Situ Chemical Chemical Oxidation (ISCO)

In Situ Chemical Oxidation (ISCO) is a remedial technique that introduces a chemical oxidant into the subsurface to oxidize contaminants as a method of converting them to innocuous byproducts such as carbon dioxide, chloride, or water. In situ processes involve placement of oxidants in direct contact with the contaminated soil and groundwater and can be applied in the saturated or unsaturated portion of the subsurface. The most common oxidants used for ISCO are permanganate (MnO4 – ), persulfate (S2O8 2- ), hydrogen peroxide (H2O2), and ozone (O3).  

1) Soil mixing by blending an oxidant into the soil matrix using specialized mixing tools from the ground surface This application is typical in shallow source zones, low permeability material that makes injection difficult, or source areas with significant heterogeneity.

2) Injection through dedicated injection wells or temporary direct push injection points The use of temporary direct push injection wells versus dedicated injection wells will vary based on the site geology/hydrogeology, site access, the ability to install and maintain permanent infrastructure on the site, and the anticipated number of injection events needed to meet the remedial objectives.

3)Recirculation that includes coupled injection and extraction wells This delivery method would be used to expedite pore volume flushes across a source area or when surface obstructions do not provide access for complete coverage of the target treatment area.