ETL 1110-1-158
28 Feb 95
oversize material by sieving are performed to create uniform
samples for the treatability study.
(a) Particle size reduction is performed so that samples can
be easily molded for testing. However, consideration should be
given to how this will affect the properties of the sample
relative to the waste that will be treated during full scale
remediation. For example, if a material is going to pass a 2
inch field screen during full scale remediation, then it would be
inappropriate to grind the sample in a mortar and pestle prior to
testing during the treatability study.
(b) Samples are typically homogenized by a mechanical mixer
in the laboratory. In some instances, samples have been
homogenized in the field so that extra material can be stored on-
site. This material has then been provided to potential bidders
so that they could perform treatability studies using their own
S/S reagents and mix ratios.
(3) Initial Sample Characterization. Initial sample
characterization consists of performing both physical and
chemical tests. Physical characterization tests typically
performed include moisture content, grain size distribution,
Atterberg limits, compaction, and possibly other tests depending
on the project. Chemical testing typically performed includes
total chemical analysis and leaching tests for the contaminants
of concern. Refer to Paragraph 4.i. of this letter for
additional information on typical characterization testing.
(4) Replicate Testing. Replicate testing is performed
during various stages of a treatability study to determine the
reproducibility of the chemical and physical test results. The
amount of replicate testing depends on the type and phase of the
project and on the amount of sample available. Replicate testing
is typically performed during initial characterization to verify
the uniformity of the samples being tested. Two or three sets of
replicate tests are generally performed. Replicate testing can
be performed by dividing the homogenized sample into two or three
subsamples and performing identical sets of tests on each
subsample.
g. Treatability Study Procedures. Following initial
characterization, several reagents are selected and numerous mix
ratios of waste, reagents, and water are prepared and tested to
determine the optimum mix ratio. Mix ratio (MR) is defined as
follows:
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