Rittenhouse (1993) wrote about CaO as an effec-
of heavy metals. The process using soluble sili-
tive reagent for the destruction of CCl4. He dis-
cate and cement additives gave the best contain-
ment of the heavy metals.
cussed the work of O. Koper, Y.-Xi Li, and K.J.
Crawley et al. (1984) outlined techniques for
Klabunde at Kansas State University.
using hydrated, high calcium lime to treat acidic
Soundararajan (1991) found a strong interac-
sludges. Remedial action using hydrated lime in-
tion between high calciumfly ash and polychlo-
jection proved very effective in preventing
rinated biphenyls (PCBs) resulting in the total de-
groundwater pollution under and around acid
struction of PCBs. Although he concluded that a
waste pits. Morgan et al. (1984) developed and
catalyst was probably responsible for the PCB de-
tested a variety of lime and by-product mixtures
struction, the specific catalyst responsible is un-
in treating oil refinery sludges. Blacklock et al.
known. Einhaus et al. (1991) reported that PCB-
(1982, 1984) described a technique for injecting a
contaminated soil treated with quicklime and
lime/fly ash grout into landfills. Francis (1984)
water significantly reduced (60 to 80%) PCB con-
reported an interesting application of hydrated
centrations after five hours of treatment. How-
lime and limestone (oyster shell) to a landfill cap
ever, they concluded that use of reactive quick-
to maintain alkaline conditions inside an indus-
lime as an in-situ treatment may be counterpro-
trial waste landfill.
ductive due to the potential for migration of PCBs
In 1971, EIF (Ecology of France) developed
as vapor or airborne particulates. Sediak et al.
lime based fixation technology to detoxify wastes
(1991) attributed most PCB losses to volatiliza-
rich in organic content (Separation and Recovery
tion due to the high heat of reaction for the CaO
Systems 1987). The examples of organic wastes
hydration reaction. They concluded that the
treated with the technology include crude oil,
"quicklime" treatment, per se, was not an effec-
refinery intermediate or final products, halogen-
tive treatment for PCB-contaminated soil.
ated chemicals (e.g., PCBs), pesticides, sludges,
Lime and lime products are useful in the engi-
tars, painting wastes, and acid sludges. The per-
neered disposal of nonhazardous and hazardous
meability of the treated and compacted refinery
wastes. In some cases lime can be used to convert
impoundment sludge waste was less than 1.0
hazardous waste to nonhazardous waste. Malone
1012 cm s1.
(1984) reported that lime has great potential as a
neutralizing and cementing agent in waste man-
In Dallas, Texas, Morgan et al. (1984) used sev-
eral solidification agents to treat 19 million liters
agement. Furthermore, he suggested that appli-
of 30-year-old refinery oil sludge. The best solid-
cation of lime in hazardous waste reduction pro-
ifying agent found was fresh and stale cement
cesses should increase because new ideas of its
kiln dust. Furthermore, the kiln dust was also
use in liners, lime/fly ash grout injection, and
tested in combination with small amounts of sul-
enhancement of methane production have been
fur, cement and lime. Excellent solidification was
evaluated and found safe and useful. Lime stimu-
observed with cement and lime. Sulfur did not in-
lates activity of anaerobic methane generating
crease the strength significantly. The solidifica-
bacteria responsible for the decay of refuse. Meth-
tion process is simple, economical, and poten-
anogenic bacteria function best in the pH ranges
tially applicable to other waste-disposal sites.
of 6.4 to 7.4; however, some methane producers
Zenobia and Turco (1985) studied the lime-
can operate at high pHs of 9.0 (Klass 1984). Lime
based stabilization technique to remediate haz-
in the form of quicklime is also used in drying
ardous waste site containing basins of inorganic
semisolid wastes. The hydration reaction of
sludges, incineration residues, and spent bio-
quicklime eliminates water from the system and
mass. They found that fly ash in combination
produces a dry product which is easy to handle.
with lime and lime kiln dust were the best stabi-
Malone and May (1991) found that the por-
lizing agents. In France, Such and Roux (1981)
osity and permeability of lime-amended soil
treated oil spills with quicklime and hydrophobic
were greatly reduced by precipitation of contam-
lime (Boelsing reagent, see DCR Technologies).
inants in intergranular spaces in the soil. Initially
the amended soil had a permeability of 3.5 106
They reported that the chemical reaction of dehy-
cm s1; after 20 pore volumes of an acidic waste
dration occurred immediately in quicklime and
relatively delayed with hydrophobic lime.
had passed the column, the permeability
decreased to 4.0 108 cm s1. In contrast, the per-
Koper et al. (1993) reported that CaO is an
meability of the untreated soil ranged from 4.0
effective solid reagent for destruction of chloro-
106 cm s1 to 1.0 106 cm s1 after contact with
carbons (CCln). Furthermore, in a editorial note,
2
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