| Soil Types
portion of table now presented: |
| Soil
Classification |
Soil
classification is a semi-empirical measurement of sand,
silt, clay, gravel, and loam content. Several soil
classification schemes are in use and include the ASTM
Standard D 2488-90, Practice for Description and
Identification of Soils (Visual-Manual Procedure), and
the USDA and CSSC systems. |
Yes |
Soil
classification is an important characteristic for
assessing the effect on cost or performance of all
technologies shown on Table D-1. For example, in soil
vapor extraction, sandy soils are typically more amenable
to treatment than clayey soils. (See related information
under clay content and/or particle size distribution.) |
| Clay
Content and/or Particle Size Distribution |
Clay
content and/or particle size distribution is measured
using a variety of soil classification systems, including
ASTM D 2488-90 under soil classification. |
Yes |
Clay and
particle size distribution affect air and fluid flow
through contaminated media. In slurry phase
bioremediation systems, particle size affects ability to
hold media in suspension. In soil washing, the particle
size/contaminant concentration relationship affects
potential for physical separation and volume reduction.
For thermal desorption systems, clay and particle size
affects mass and heat transfer, including agglomeration
and carryover to air pollution control devices. |
| Aggregate
Soil Properties portion of table now presented: |
| Hydraulic
Conductivity /Water Permeability |
Hydraulic
conductivity/water permeability can be determined through
several procedures. Hydraulic conductivity, which is a
measure of the ease of water flow through soil, is
typically calculated as a function of permeability or
transmissivity. ASTM D 5126-90, Guide for Comparison of
Field Methods for Determining Hydraulic Conductivity in
the Vadose Zone, is a guide for determining hydraulic
conductivity. Water permeability is often calculated by
pumping out ground water, measuring ground water
draw-down rates and recharge times through surrounding
monitoring wells, and factoring in the distance between
the wells and the pump. Method 9100 in EPA SW-846 is used
to measure permeability, as well as several ASTM
standards: D 2434-68 (1974), Test Method for Permeability
of Granular Soils (Constant Head); D 4630-86, Test Method
for Determining Transmissivity and Storativity of Low
Permeability Rocks by In Situ Measurements Using the
Constant Head Injection Test; and D 4631-86, Test Method
for Determining Transmissivity and Storativity of Low
Permeability Rocks by In Situ Measurements Using the
Pressure Pulse Technique. |
Yes |
This
characteristic is important in ground water remediation
technologies including in situ ground water
bioremediation, ground water sparging, and pump and treat
systems. Hydraulic conductivity and water permeability
affect the zone of influence of the extraction wells and,
therefore, affect the number of wells needed for the
remediation effort and the cost of operating the
extraction wells. |
| Moisture
Content |
Procedures
for measuring soil moisture content are relatively
standardized. Soil moisture content is typically measured
using a gravimetric ASTM standard, D 2216-90, Test Method
for Laboratory Determination of Water (Moisture) Content
of Soil and Rock. |
No |
The
moisture content of the matrix typically affects the
performance, both directly and indirectly, of
technologies including soil vapor extraction, and ex situ
technologies such as stabilization, incineration, and
thermal desorption. For example, air flow rates during
operation of soil vapor extraction technologies are
affected by moisture content of the soil. Thermal input
requirements and air handling systems for incineration
and desorption technologies can also be affected by soil
moisture content. (Effects of moisture content on
operation of technologies are discussed in Table D-4). |
| Air
Permeability |
Air
permeability is a measure of the ease of air flow through
soil and is a calculated value. For example, air
permeability may be calculated by applying a vacuum to
soil with a pump, measuring vacuum pressures in
surrounding monitoring wells, and fitting the results to
a correlation derived by Johnson et al., 1990. |
Yes |
This
characteristic is important for in situ soil remediation
technologies that involve venting or extraction. Air
permeability affects the zone of influence of the
extraction wells, and, therefore, affects the number of
extraction wells needed for the remediation effort and
the cost of operating the extraction wells. |
| pH |
pH is a
measure of the degree of acidity or alkalinity of a
matrix. Procedures for measuring and reporting pH are
standardized and include EPA SW-846 Method 9045 and ASTM
methods for soil (ASTM D 4972-89, Test Method for pH of
Soils) and ground water (ASTM D 1293-84). |
No |
The pH of
the matrix can impact the solubility of contaminants and
biological activity. Therefore, this characteristic can
affect technologies such as soil bioventing, soil
flushing, land treatment and composting and in situ
ground water bioremediation. pH can also affect the
operation of treatment technologies (see Table D-4). pH
in the corrosive range (e.g., <2 and >12) can
damage equipment and typically requires use of personal
protection equipment and other special handling
procedures. |
| Porosity |
Porosity
is the volume of air- or water-filled voids in a mass of
soil. Procedures for measuring and reporting porosity are
standardized. Porosity is measured by ASTM D 4404-84,
Test Method for Determination of the Pore Volume and Pore
Volume Distribution of Soil and Rock by Mercury Intrusion
Porosimetry |
No |
This
characteristic is important for in situ technologies,
such as soil bioventing, soil vapor extraction, and
ground water sparging, that rely upon use of a driving
force for transferring contaminants into an aqueous or
air-filled space. Porosity affects the driving force and
thus the performance that may be achieved by these
technologies. |
| Transmissivity |
Transmissivity,
the flow from a saturated aquifer, is the product of
hydraulic conductivity and aquifer thickness. |
No - The
measurement of hydraulic conductivity is important to
document, because transmissivity is a product of
hydraulic conductivity and aquifer thickness, it would
not be necessary to document the measurement procedure
for this characteristic. |
This
characteristic is important for ground water pump and
treat systems. Transmissivity affects the zone of
influence in this type of remediation, which impacts the
number of wells and the cost of operating the wells. |
| Organics portion of
table now presented: |
| Total
Organic Carbon (TOC) |
TOC is a
measure of the total organic carbon content of a matrix.
Measurement of TOC is standardized (e.g., Method 9060 in
EPA SW-846) |
No |
TOC
affects the desorption of contaminants from soil and
impacts in situ soil remediation, soil washing, and in
situ ground water bioremediation. |
| Oil &
Grease (O&G) or Total Petroleum Hydrocarbons (TPH) |
Procedures
for measuring O&G and TPH are standardized. O&G
is measured using Method 9070 in EPA SW-846, and TPH is
measured using Method 9073. A TPH analysis is similar to
an O&G analysis with an additional extraction step.
TPH does not include nonpetroleum fractions, such as
animal fats and humic and fulvic acids. |
No |
O&G
and TPH affect the desorption of contaminants from soil.
For thermal desorption, elevated levels of TPH may result
in agglomeration of soil particles, resulting in longer
residence times. |
| Nonaqueous
Phase Liquids (NAPLs) |
There is
no standard measurement method for determining the
presence of NAPLs; rather, their presence is determined
by examining ground water and identifying a separate
phase. The presence of NAPLs is reported as either being
present or not present. |
Yes |
NAPLs may
be a continuing source of contaminants for in situ
technologies. NAPLs may lead to increased contaminant
loads and thus to greater costs or longer operating
periods for achieving cleanup goals. |