| Popis: |
Contamination of the subsurface by persistent organic contaminants remains a significant problem, even after decades of research on remediation. First, approaches focused on excavation, pump and treat via activated carbon, bioremediation, and natural attenuation. In the 1990s the first reports on in situ chemical oxidation (ISCO) were published, which is a technique involving the introduction of chemical oxidants into the subsurface in order to transform contaminants into less harmful substances. Hydrogen peroxide was the first chemical oxidant investigated and used in full scale. Shortly after ozone and permanganate came into use. In the past few years persulphate has provided yet another option. In this chapter, the chemical reactions of the most common chemical oxidants used in ISCO are reviewed and the applicability of the two most relevant modified Fenton's reagent and activated sodium persulphate are demonstrated using the Kaergaard Plantation megasite in Denmark as case study. This site represents one of the most difficult remediation challenges in Scandinavia and, therefore, regulatory agencies have been evaluating remediation techniques for source area remediation. |
