Standard Guide for Estimation of LNAPL Transmissivity

SIGNIFICANCE AND USE
Application:
LNAPL transmissivity is an accurate metric for understanding LNAPL recovery, is directly proportional to LNAPL recoverability and tracking remediation progress towards residual LNAPL saturation.
LNAPL transmissivity can be used to estimate the rate of recovery for a given drawdown from various technologies.
LNAPL transmissivity is not an intrinsic aquifer property but rather a summary metric based on the aquifer properties, LNAPL physical properties, and the magnitude of LNAPL saturation over a given interval of aquifer.
LNAPL transmissivity will vary over time with changing conditions such as, seasonal fluctuations in water table, changing hydrogeologic conditions and with variability in LNAPL impacts (that is, interval that LNAPL flows over in the formation and LNAPL pore space saturation) within the formation.
Any observed temporal or spatial variability in values derived from consistent data collection and analysis methods of LNAPL transmissivity is not erroneous rather is indicative of the actual variability in subsurface conditions related to the parameters encompassed by LNAPL transmissivity (that is, fluid pore space saturation, soil permeability, fluid density, fluid viscosity, and the interval that LNAPL flows over in the formation).
LNAPL transmissivity is a more accurate metric for evaluating recoverability and mobile LNAPL than gauged LNAPL thickness. Gauged LNAPL thickness does not account for soil permeability, magnitude of LNAPL saturation above residual saturation, or physical fluid properties of LNAPL (that is, density, interfacial tension, and viscosity).
The accurate calculation of LNAPL transmissivity requires certain aspects of the LNAPL Conceptual Site Model (LSCM) to be completely understood and defined in order to calculate LNAPL drawdown correctly. The methodologies for development of the LSCM are provided in Guide E2531. The general conceptual site model aspects applicable to this guide include:
Equilibrium ...
SCOPE
1.1 This guide provides field data collection and calculation methodologies for the estimation of light non-aqueous phase liquid (LNAPL) transmissivity in unconsolidated porous sediments. The methodologies presented herein may, or may not be, applicable to other hydrogeologic regimes (for example, karst, fracture flow). LNAPL transmissivity represents the volume of LNAPL (L3) through a unit width (L) of aquifer per unit time (t) per unit drawdown (L) with units of (L2/T). LNAPL transmissivity is a directly proportional metric for LNAPL recoverability whereas other metrics such as apparent LNAPL thickness gauged in wells do not exhibit a consistent relationship to recoverability. The recoverability for a given gauged LNAPL thickness in a well will vary between different soil types, LNAPL types or hydrogeologic conditions. LNAPL transmissivity accounts for those parameters and conditions. LNAPL transmissivity values can be used in the following five ways: (1) Estimate LNAPL recovery rate for multiple technologies; (2) Identify trends in recoverability via mapping; (3) Applied as a leading (startup) indicator for recovery; (4) Applied as a lagging (shutdown) indicator for LNAPL recovery; and (5) Applied as a robust calibration metric for multi-phase models (Hawthorne and Kirkman, 2011 (1) and ITRC ((2)). The methodologies for LNAPL transmissivity estimation provided in this document include short-term aquifer testing methods (LNAPL baildown/slug testing and manual LNAPL skimming testing), and long-term methods (that is, LNAPL recovery system performance analysis, and LNAPL tracer testing). The magnitude of transmissivity of any fluid in the subsurface is controlled by the same variables (that is, fluid pore space saturation, soil permeability, fluid density, fluid viscosity, the interval that LNAPL flows over in the formation and the gravitational acceleration constant). A direct mathematical relationship exists between the...

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E2856 – 11
Standard Guide for
1
Estimation of LNAPL Transmissivity
This standard is issued under the fixed designation E2856; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope ing the relationship of discharge versus drawdown for the
occurrence of LNAPLin a well, which can be used to estimate
1.1 This guide provides field data collection and calculation
the transmissivity of LNAPL in the formation. The focus,
methodologies for the estimation of light non-aqueous phase
therefore,istoprovidestandardmethodologyonhowtoobtain
liquid (LNAPL) transmissivity in unconsolidated porous sedi-
accurate measurements of these two parameters (that is,
ments. The methodologies presented herein may, or may not
discharge and drawdown) for multi-phase occurrences to
be, applicable to other hydrogeologic regimes (for example,
estimate LNAPL transmissivity.
karst, fracture flow). LNAPL transmissivity represents the
3
1.2 Organization of this Guide:
volume of LNAPL(L ) through a unit width (L) of aquifer per
2
1.2.1 Section 2 presents documents referenced.
unit time (t) per unit drawdown (L) with units of (L /T).
1.2.2 Section 3 presents terminology used.
LNAPL transmissivity is a directly proportional metric for
1.2.3 Section 4 presents significance and use.
LNAPL recoverability whereas other metrics such as apparent
1.2.4 Section 5 presents general information on four meth-
LNAPL thickness gauged in wells do not exhibit a consistent
ods for data collection related to LNAPL transmissivity calcu-
relationship to recoverability. The recoverability for a given
lation. This section compares and contrasts the methods in a
gauged LNAPLthickness in a well will vary between different
way that will allow a user of this guide to assess which method
soil types, LNAPLtypes or hydrogeologic conditions. LNAPL
most closely aligns with the site conditions and available data
transmissivity accounts for those parameters and conditions.
collection opportunities.
LNAPLtransmissivity values can be used in the following five
1.2.5 Sections 6 and 7 presents the test methods for each of
ways: (1) Estimate LNAPL recovery rate for multiple tech-
the four data collection options.After reviewing Section 5 and
nologies; (2) Identify trends in recoverability via mapping; (3)
selecting a test method, a user of this guide shall then proceed
Applied as a leading (startup) indicator for recovery; (4)
to the applicable portion of Sections 6 and 7 which describes
Applied as a lagging (shutdown) indicator for LNAPL recov-
the detailed test methodology for the selected method.
ery; and (5) Applied as a robust calibration metric for multi-
2 1.2.6 Section 8 presents data evaluation methods. After
phase models (Hawthorne and Kirkman, 2011 (1) and ITRC
reviewing Section 5 and the pertinent test method section(s) of
((2)). The methodologies for LNAPLtransmissivity estimation
Sections6and7,theuserofthisguideshallthenproceedtothe
provided in this document include short-term aquifer testing
applicable portion(s) of Section 8 to understand the method-
methods (LNAPL baildown/slug testing and manual LNAPL
ologies for evaluation of the data which will be collected. It is
skimming testing), and long-term methods (that is, LNAPL
highly recommended that the test methods and data evaluation
recovery system performance analysis, and LNAPL tracer
procedures be understood prior to initiating data collection.
testing). The magnitude of transmissivity of any fluid in the
1.3 The values stated in inch-pound units are to be regarded
subsurface is controlled by the same variables (that is, fluid
as standard. The values given in parentheses are mathematical
pore space saturation, soil permeability, fluid density, fluid
conversions to SI units that are provided for information only
viscosity, the interval that LNAPL flows over in the formation
and are not considered standard.
and the gravitational acceleration constant). A direct math-
1.4 This standard does not purport to address all of the
ematical relationship exists between the transmissivity of a
safety concerns, if any, associated with its use. It is the
fluid and the discharge of that fluid for a given induced
responsibility of the user of this standard to establish appro-
drawdown. The methodologies are generally aimed at measur-
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1
ThisguideisunderthejurisdictionofASTMCommitteeE50onEnvironmental
1.5 This document is applicable to wells exhibiting LNAPL
Assessment, Risk Management and CorrectiveAction and is
...

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