Chemical treatment technologies rely on a range of chemical reactions to destroy, transform or immobilise soil contaminants. For remediation they are most commonly applied as:

• PRBs 

• Stabilisation

• Chemical Oxidation

Permeable Reactive Barriers

A permeable reactive barrier (PRB) is an engineered treatment zone installed within the saturated zone that allows groundwater to pass through whilst immobilising or transforming the pollutants. Typical designs include funnel and gate systems or continuous reactive barriers. PRBs comprise physical (e.g. SVE, air sparging), chemical (e.g. lime, zero valent iron) and/or biological treatment technologies (bioventing, biosparging).

Stabilisation

Stabilisation processes immobilise contaminants within the soil matrix by either physical and/or chemical processes.  They generally involve the application of a binding agent (e.g. cement, lime) which reacts with the soil/contaminant and moisture within the soil. Chemically, contaminants can be precipitated as hydroxides or incorporated within cement hydrates. The process also physically encapsulates contaminants within the cement matrix. Stabilisation processes are often used to provide a capping system where they can also improve the engineering properties of a surface soil.

Chemical Oxidation

Certain contaminants in soil and groundwater can be converted into other chemicals with the addition of oxygen. This involves the breaking of chemical bonds and removal of electrons which are transferred from the contaminant to the oxidant. Commonly used oxidants for remediation include hydrogen peroxide, persulphate, potassium permanganate and ozone. Products manufactured specifically for remediation using this technology (primarily in-situ) are also available (e.g. Regenesis RegenOx™). Chemical oxidation can be applied in-situ or ex-situ but is only effective on certain hydrocarbons within soils with a low organic content.