TCLP (EPA Method 1311 Extraction for
DCR-treated material was requested, with the pro-
Volatiles [8240] and Semivolatiles [8270])
viso that the cylinder be crushed to the minimum
TCLP (EPA Method 1311 Extraction for Met-
extent necessary to pass through the 9.5 mm sieve
als, ICP EPA Method 6010)
(specified in the TCLP test) before leaching.
TCLP (EPA Method 1311 Extraction for Pesti-
cides, EPA Method 8081).
RESULTS AND DISCUSSION
After the sample was shipped, several addi-
tional larger-scale (1.5 kg) scoping experiments
64.7% DCR-treated product
were completed with SOUND/epic's high-inten-
Two basic analytical approaches are currently
sity Eirich mixer. Through these later determina-
utilized by the U.S. EPA to evaluate reduction in
tions it was found that, at the larger batch size
contaminant mobility and total constituent
and with more aggressive mixing, an acceptable
concentrations. These are total waste analyses (or-
product could be obtained with only a 23% CaO
ganic solvent extraction followed by GC or GC/
addition to lime-milk pretreated soil (total CaO
MS analyses) and leachability, usually by the Toxic
addition, including preparation of lime milk was
Characteristic Leaching Procedure (TCLP). Table
27.4%).
3 presents the results of the SOUND/epic and
Because the 27.4% CaO addition is more repre-
Corps of Engineers Environmental Laboratory
sentative of what might be utilized in field appli-
analyses of RMA sample 24216 before and after
cations, samples of this DCR-treated material were
DCR treatment with 64.7% CaO. For these analy-
used to determine the following geophysical
ses, the raw soil and treated product were first
properties:
analyzed for total volatile constituents using stan-
dard U.S. EPA 8260 methods, and then additional
Optimum Moisture (ASTM 1557--Std. Proctor
samples were extracted with an appropriate ex-
Density Measurement)
traction solvent (e.g., methylene chloride) for
Compressive Strength (ASTM 2166--Use ex-
semivolatile constituent analyses using U.S. EPA
truded Proctor Test samples)
3550/8270 procedures.
Permeability (ASTM D 5084--Use extruded
Proctor Test samples).
Total waste analyses
The volatile lower molecular weight alky-
On 23 March 1995 approximately 13.6 kg of
lated and chlorinated benzenes in the RMA soil
the 27.4% DCR-treated soil was delivered to
sample are essentially eliminated during the
Southern California Soil and Testing in San Di-
DCR process (Table 3). This is due to volatiliza-
ego, California. This material was used for Proc-
tion and/or steam stripping during the exo-
tor maximum density/optimum moisture content
thermic hydration of calcium oxide to calcium
determinations, and one of the compacted 4-in.-
hydroxide, and in field implementation these
diam. cylinders from these tests was then used
constituents can be captured using transport-
for determination of unconfined compressive
able treatment units (TTUs) equipped with
strength. One of the other Proctor cylinders was
modular emissions control systems. Their re-
prepared for permeability analysis and shipped
moval is important in that they constitute the
via Federal Express under full chain of custody
more water-soluble constituents, which can con-
to WallaceKuhl & Associates in Sacramento,
tribute to leachate or groundwater contamina-
California.
tion if not otherwise controlled.
A third Proctor cylinder was allowed to cure
With regard to the pesticides and semivolatile
and was set aside for additional chemical analy-
organics in the RMA soils, it should be empha-
ses to assess the effects of lower DCR reagent
sized again that the DCR process is not a destruc-
utilization and sample compaction on pesticide
tive technology. Any liquid (or solubilized) or-
sequestering and leachability. This third com-
ganic wastes treated by the DCR process are
pacted cylinder sample was shipped via Federal
homogeneously dispersed into very fine (submi-
Express under chain of custody to the U.S. Army
cron-sized), hydrophobic particles. Since the pes-
Corps of Engineers Environmental Laboratory in
ticides present in the RMA soil samples are for
Hubbardston, Massachusetts, on 10 April 1995.
the most part solids under ambient-temperature
The same suite of analyses used for the raw un-
conditions, the ADM soy oils were added in an
treated soil sample and loose (uncompacted) 64.7%
effort to partially "solubilize" them and facilitate
8
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