Overview of Soil Remediation Systems
Remediation of contaminated soils generally is accomplished
by using one or more of three types of systems: 1) in
situ, 2) prepared bed, and 3) in-tank reactor.3
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An in situ treatment system consists of treating contaminated
soil in place, where the contamination is located, i.e..
the contaminated soil is not moved from the ground. Milestone
publications containing scientific and engineering information
specifically addressing in situ treatment include:
"Review of In-Place Treatment Techniques for Contaminated
Surface Soils, Volume 1: Technical Evaluation and
Volume 2: Background Information for In Situ Treatment,"23"
24
an update of Volume 1, "Handbook on In Situ
Treatment of Hazardous Waste-Contaminated Soils,"3
"Bioremediation of Contaminated Surface Soils,"22
and "In
Situ Biological Treatment of Hazardous Waste-Contaminated
Soils."32
In a prepared bed system, the contaminated soil may be
either: 1) physically moved from its original site to a newly
prepared area, which has been designed to enhance treatment
and/or to prevent transport of contaminants from the
site; or 2) removed from the site to a storage area while the
original location is prepared for use, then returned to the
bed, where treatment is accomplished. Preparation of the
bed may consist of such activities as placement of a clay or
plastic liner to retard transport of contaminants from the
site, or addition of uncontaminated soil to provide additional
treatment medium. Treatment may be enhanced with
biological and/or physical/chemical methods, as with in situ
systems.22
Prepared bed treatment approaches are based on
modifications of principles developed in the area of land
application of solid and liquid wastes, and in the area of land
treatment of hazardous wastes.22
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In-tank treatment systems
are used for treatment of contaminated soil, where the
soil is physically removed and placed in an enclosed reactor
based upon batch, complete mix, or plug flow systems commonly
used in chemical and environmental engineering systems;
the soil may be in an unsaturated or a saturated physical
form. Common tank treatment systems include composting,
slurry-phase treatment, and solid-phase treatment