28 Feb 95
(2) Permeability. A maximum allowable permeability is
sometimes specified for treated material by regulators. However,
permeability testing should be used with caution since higher
permeability is not necessarily related to leachability and the
placement of low permeability waste within a landfill may result
in ponded water within the landfill. The permeability of treated
material is generally measured with a flexible wall permeameter
using the test procedure described in ASTM D 5084-90. If
permeability testing is to be performed as part of a treatability
study, consideration needs to be given to the appropriate
confining pressure, gradient, and permeating fluid which will be
representative of field conditions.
(3) Durability. Durability tests are sometimes performed on
treated samples during a treatability study. These tests are
often used by comparing results with other test specimens (i.e.,
how many cycles can one mixture withstand versus a different
mixture). The test procedures specified for durability testing
of waste are entitled: Test Method for Determining the
Resistance of Solid Wastes to Freezing and Thawing (ASTM D 4842-
90) and Test Method for Wetting and Drying Test of Solid Wastes
(ASTM D 4843-88).
(4) Moisture-Density (Compaction Tests). Compaction tests
are run on treated and untreated material to determine compaction
requirements for treatability study test specimens.
material is often compacted to around 90 percent of maximum
density during a treatability study. It should be noted that
optimum water content for compaction is often not the optimum
water content required for hydration reactions. The two most
commonly used compaction test methods are the standard (ASTM D
698-91) and modified (ASTM D 1557-91) compaction tests.
(5) Index Properties. Various index properties may be
valuable in characterizing both untreated and treated material.
The following is a partial list of these tests. Additional
information on these test methods can be found in EPA/625/6-
(a) Moisture Content (ASTM D 2216-90): Generally used as a
classification tool to determine the amount of free water present
in a material. This test is often used to determine if
pretreatment to remove free liquids is necessary. Moisture
content can also be used to determine how well a sample has been
homogenized prior to initial characterization testing.
(b) Apparent Specific Gravity and Bulk Density (ASTM D 5057-
90): Bulk density is used to relate weight to volume for