Chemical reduction is a pollution treatment method that involves the use of chemicals to reduce contaminants in water or soil to less toxic forms. This method is often used to treat soil and groundwater contaminated by heavy metals, pesticides, chlorinated solvents, polycyclic aromatic hydrocarbons (PAHs) and other organic compounds.
Chemical reduction is based on the reduction of polluting compounds using chemical reducers such as iron, sulfuric acid, ascorbic acid, hydrogen sulfide and other chemicals. This method can be applied in situ (on site) or ex situ (off site).
With in situ chemical reduction, chemical reducers are injected directly into contaminated areas via wells or trenches. The chemical reducers react with the contaminants, reducing them to less toxic forms. This method is often used to treat contaminated soils.
The ex situ application of chemical reduction involves removing contaminated soil or water from the site for treatment in a centralized treatment system. Contaminants are then reduced using chemical reducers such as iron or hydrogen sulfide. This method is often used to treat contaminated groundwater.
Chemical reduction can be effective in removing contaminants from soil and groundwater, but it can also have undesirable side effects. For example, the use of chemical reducers can alter pH and environmental conditions, which can affect groundwater quality. In addition, chemical reducers can sometimes form toxic by-products that can be more difficult to eliminate.
As part of on-site or in-situother treatment methods can be used, such as anaerobic biostimulation, bioventing, composting, containment, thermal desorption, excavation, vacuum extraction, incineration, landfarming, chemical washing, chemical oxidation, phytomanagement, pyrolysis, stabilization, stripping, biological treatment or granulometric sorting.