Potassium Permanganate Soil Remediation

The Environmental Protection Agency explains chemical oxidation as a method that "uses chemicals called oxidants to destroy pollution in soil and groundwater. Oxidants help change harmful chemicals into harmless ones, like water and carbon dioxide." This newer technology destroys several types of chemicals, such as fuels, solvents, pesticides and organic contaminants. Potassium permanganate is one effective chemical used in this type of oxidation.

Environmental Cleanup

• In environmental remediation of contamination, sodium permanganate use for oxidation is proven to be highly effective in-situ (below ground) remediation because the chemicals act quickly. Disadvantages of chemical oxidation include its costliness (though oxidation is far less costly than removing the contaminated soil or water to a treatment facility), the complications in controlling some of its chemical reactions and the fact that oxidation is nonselective (everything will be oxidized, not just contaminants). Good testing before and during oxidation and careful preplanning usually make this process safe.

Potassium Permanganate

• Potassium permanganate is one of six chemicals used to oxidize harmful contaminants in aquifers, soil, groundwater and water supply systems. It is injected into aquifers, soil or groundwater as a liquid and mixed in. It has the lowest oxidation potential of the six main chemicals used for oxidation. The costs associated with using potassium permanganate specifically ranges from moderate to high compared to the other oxidation chemicals. It does produce byproducts, such as Mn(VI), and is known to create subsurface fouling because of the MnO2 the process generates.

Preparation

• The Environmental Protection Agency surveys the polluted area and tests the soil and groundwater. This determines what contaminants are present, what oxidant is needed to break them down and where to drill to add the oxidant to the area. How quickly the project can be completed is determined by how bad the contamination is and what drilling method can be used to clean it up. The condition of the soil or water flow in the area also impacts the length of time it takes to clean the area.

Process

• Wells are drilled at several places and at different depths in the area containing the pollution, whether it is soil or a water source. The chemical oxidant is injected into these wells. In the case of potassium permanganate, a liquid form will be flushed into the wells. The potassium permanganate mixes with the harmful chemicals in the soil or water and breaks them down. What is left behind are clean soil and water and some harmless by-products. Sometimes the chemical is flushed into one well and out another well, then the water or soil is re-circulated back into the area through the first well.