Soil
Washing Processes and How They Work (Or Don't Work)
David W. Bieber, John Y. Mason, Robert H. Wohleb
Soil
washing is a young technology for the remediation of contaminated soils.
Typical washing schemes have relied on three basic processes to accomplish their
remediation goals. These three processes are contaminant concentration,
contaminant destruction through chemical oxidation, and surfactant activated
bio-enhanced contaminant destruction.
Soil
washing processes that focus on concentration, isolate the
soil
fraction
containing the majority of the contaminants (i.e. clays). They are most
practical for the remediation of non-organic-contaminants.
Soil
Washing using
chemical oxidation relies on the destruction of contamination by strong
oxidizing agents such as hydrogen peroxide. Surfactant activated bio-enhanced
destruction operates on the principle of solubilizing contamination to increase
its surface area, which dramatically increases bioremediation rates. The
chemical oxidation process has traditionally been used to remediate organic
contaminants Chemical oxidation is loosing favor as surfactant activated
bio-enhanced destruction becomes more common.
Like all emerging technologies, soil
washing has had its share of
growing-pains. Initial
soil
washing efforts suffered from high costs and
inefficient equipment. As the actual chemical, biological, and mechanical
processes involved in
soil
washing were understood, the initial problems were
overcome. Current generation, transportable
soil
washing systems are capable of
washing over 500 metric tons of
soil
per day. The primary limiting factor on the
quantity of
soil
that can be processed in a day is the percent of material less
than 100 microns present in the
soil
. When properly applied,
soil
washing is a
quick and cost effective method for remediating contaminated
soil
.
AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995