LNAPL Transmissivity

The rate at which a volume of light nonaqueous phase liquid, such as oil, will flow through a unit width of porous material, such as soil, for a unit gradient is termed LNAPL transmissivity. Being able to measure LNAPL transmissivity is an important aspect of environmental assessment work. It is possible to measure LNAPL transmissivity via several methodologies (for example, baildown tests, recovery data, soil core and tracer test analyses), but currently no consensus exists on standard methodologies.

Subcommittee E50.04 on Corrective Action is currently working on such a proposed standard, WK26425, Guide for Evaluating LNAPL Transmissivity. The subcommittee is part of ASTM International Committee E50 on Environmental Assessment, Risk Management and Corrective Action. "By calculating such a rate, engineers and geologists can make improved decisions on the selection and design of subsurface remediation technologies and determine when hydraulic recovery is no longer practical," says Tripp Fischer, project manager, Brownfield Associates Inc., and chairman, E50.04. "The proposed standard will assist users in conducting field experiments, calculating transmissivity and validating whether or not the assumptions in the calculations match field observations."

Anyone who makes decisions regarding sites that contain LNAPL in the subsurface will be potential users of WK26425. Regulators will be able to use WK26425 to validate claims made in reports received from industry while private industry engineers and geologists will be able to use the proposed standard as a technical reference. Subcommittee E50.04 invites all interested parties to participate in its standards developing activities.

CONTACT Technical Information: Tripp Fischer, Brownfield Associates Inc. • West Grove, Pa. • Phone: 610-869-3322 • E-mail: tfischer@brownfield-assoc.com O ASTM Staff: Daniel Smith • Phone: 610-832-9727 • E-mail: dsmith@astm.org O Upcoming Meeting: April 19-22 • April Committee Week • St. Louis, Mo.

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