Soil Remediation and Disposal

For the treatment of contaminated sites, securing as well as remediation methods are applied. While remediation achieves decontamination or reduction of pollutants, securing sets up technical barriers for the protection of the environment. Since the source of contamination remains in place and the technical barriers are subject to aging and environmental influences, securing measures often represent only a time restricted solution and future remediation activities become necessary. Remediation methods are classified according to their operation location as well as to processing aspects. Thus, ex situ and in situ processes are available on the one hand, and thermal, chemical, physical, and biological processes on the other. The ex situ processes require excavation of the contaminated soil and soil treatment either at the site (on-site remediation) or at an external soil treatment plant (off-site remediation). In contrast, in situ treatment takes place at the site in the contaminated soil itself, without any soil excavation. Thermal processes are used for the treatment of highly concentrated organic pollutants, but they are suitable only to a small extent for the elimination of heavy metals. With soil scrubbing, the coarse-grain fraction >63 μm is purified, transferring the pollutants into the water phase and/or into the fine-grain fraction. This fine fraction is highly loaded with pollutants and thus has to be treated and disposed of afterwards. The biopile process is applied on a large scale as a state-of-the-art technology. It is an effective process for the treatment of biologically degradable pollutants such as mineral oil and its derivatives, aliphatic hydrocarbons, phenols, formaldehyde, and other soil contaminants. In remediation practice, there is a trend toward actions with a minimum of requirements. Contaminated sites are remediated or secured, depending on the intended after-use, e.g., housing, development of commercial or industrial facilities, or as recreational areas. Depending on the kind of use, specific target values have to be met after treatment. If the contaminated site is not being used and so far no major dangerous contamination of the groundwater, surface water, etc. has occurred, 259