which lowers the hydraulic conductivity, and the
24 volumes of acidic waste. The lime-amended
hydrophobicity of the product, which resists ab-
soil decreased the permeability, reduced the
sorption of water. During the initial mixing step,
amount of leachate passing through the liner, and
other reagents can be added for specific reactions.
reduced the total dissolved solvent content, trace
metal, and radionuclide concentrations in the
For example, a hydrophobized nucleophilic re-
waste that moved through the liner. The lime-
agent has been used for dehalogenation of PCBs
amended liner was considered to be a very suc-
(Payne et al. 1992). Remediation of heavy metals
cessful method for reducing the discharge of pol-
relies upon the formation of insoluble heavy
lutants from acid waste piles.
metal hydroxides and carbonates; when used to
Quicklime mixed with clay soils has been used
remediate heavy metals, hydrophilic CaO is used
to produce hard, impervious soil liners in stock
as the primary reagent (Marion et al., in prep.).
ponds, small earth dams and irrigation channels
The objectives of this project were to 1) evaluate
(Gutschick 1978). A compacted lime liner was
the DCR process for remediating soils contam-
constructed by BASF Corp. for a hazardous waste
inated with pesticides, petroleum hydrocarbons
landfill on the Island of Flotzgrun near Speyer,
(oils and fuels), and heavy metals in cold regions
Germany (BASF 1983).
and 2) evaluate DCR-treated oil-contaminated
soil as a non-frost-susceptible (NFS) construction
material. These objectives were met with three
DCR technologies
The Dispersion by Chemical Reaction (DCR)
major studies. We evaluated the DCR process to
technologies are a group of patented waste treat-
remediate 1) hydrocarbons at Eareckson AFS on
ment processes developed by F. Boelsing (Univer-
Shemya in the Aleutians, 2) pesticide-contami-
sity of Hannover, Germany) over 18 years ago in
nated soils from Rocky Mt. Arsenal, and 3)
Europe for the immobilization of heavily oiled
heavy-metal-contaminated soils from a former
sludges, water-in-oil emulsions, oil contaminated
zinc smelter site at Palmerton, Pennsylvania.
soil, industrial wastes such as acid-tars and heavy
metals (Boelsing 1988, 1995, Payne et al. 1992).
METHODS AND MATERIALS
Hydrophobized CaO is used in the DCR process
to remediate organic-contaminated materials.
This final CPAR report will focus on the high-
Calcium oxide, in its pure state, is hydrophilic.
lights of the three studies at Shemya, Rocky Mt.
Arsenal, and the Palmerton zinc smelter site, with
Hydrophobic and oleophilic lime is prepared by
primary focus on the chemistry. Other physical
treating CaO with natural fatty acids. This pro-
and chemical testing beyond that described be-
cess delays the hydration step and allows the
low and in the Results and Discussion were done at
fatty acid-coated CaO reagent to preferentially
all these sites. For a complete description of the
adsorb oils during a mixing step. The delayed
experimental work, refer to the following publi-
hydration then produces calcium hydroxide
cations: Payne et al. (1994), Brar and Marion
[Ca(OH)2], which is fractured into submicron
(1995), Marion et al. (1997), Payne and Marion (in
sized particles (eq 1). This hydration reaction is
press), Marion et al. (in prep.).
highly exothermic. Hydrate particles are homo-
geneously charged throughout their internal and
external cavities with the oil phase. The finely
Shemya study
Shemya Island (5.6 2.4 km) is located at the
dispersed Ca(OH)2 then slowly reacts with natu-
western tip of the Aleutian Archipelago, 2400 km
ral CO2 to generate relatively insoluble CaCO3
southwest of Anchorage. Historically Shemya
(eq 2):
has been uninhabited. The earliest written rec-
CaO + H2O → Ca(OH)2 + energy↑
ords of human activity were by Russians who in-
(1)
troduced blue foxes on Shemya for the purposes
Ca(OH)2 + CO2 → CaCO3 + H2O.
(2)
of fur farming in 1775. In 1943, the U.S. Army's
4th Infantry and 18th Engineering Regiments
Thus, the oil components are immobilized in a
developed Shemya and constructed a runway
CaCO3 matrix to levels passing EPA Toxic Char-
and aircraft hangers, which were used during
acteristic Leaching Procedure (TCLP) require-
World War II. Today, the U.S. Air Force occupies
ments. Other physical properties of the DCR
the entire island; the primary mission of the
product that facilitate lower chemical leaching
Eareckson Air Force Station is to monitor space
are the compactibility of the soil-like product,
and missile activities.
3
Previous Page
