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For a medley of innovative designs
NAPL FLUTe

The NAPL FLUTe system addresses the problem of locating layers, filled fractures or
globules of pure product trapped in the formation.

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Coal tar stain Rye NY

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TCE stains New Jersey

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Oil stains Ft. Wayne IN


The NAPL FLUTe is a covering for a normal blank flexible liner. The liner is “blank” in that there are no attachments to the liner. The blank liner with a NAPL FLUTe cover is normally everted into a borehole to detect the presence of NAPL. There are many applications of the blank liner as described at blank liners. The NAPL FLUTe covering of a blank liner is everted into the borehole on the outside of an ordinary blank liner. The NAPL cover is pressed against the borehole wall by the interior liner pressure. The covering is hydrophobic and quickly wicks any NAPL contacted in the fractures or pore space into the cover. The cover is dye striped on the exterior of the cover. Contact with NAPLs such as TCE or PCE dissolves the dye stripes and carriers the dye to the interior surface of the cover. The cover material is white and the displacement of the dye to the interior surface produces a strong highly visible stain on the interior surface. That stain is the indication that the cover has contacted a NAPL. The size and location of the stain are indicative of the amount of NAPL present and the nature of the source.

Some NAPL materials such as coal tar and creosote are naturally dark colored. When those materials are wicked into the covering, the dark stain appears on both the inside and outside surface of the cover. Other NAPLs such as gasoline and similar less aggressive solvents will also displace the dye stripes to the inside of the thin cover. Other NAPLs, such as coal oil, do not displace the dye stripes. However when absorbed by the cover material, those NAPLs produce a translucent appearance of the cover much like an oil stain on paper. The cover does not absorb water.

The cover only reacts to the pure product of the NAPL and does not provide a significant stain if exposed to the dissolved phase. However, the dissolved phase of chlorinated solvents for long periods will cause the dye strips to blur somewhat or produce a light pink cast due to the red stripes. However, those stains are not as obvious as the contact with the NAPL.

FLUTe has a technique called a
FACT (FLUTe Activated Carbon Technique) which does respond to the dissolved phase of many contaminants. A common practice is to combine the FACT with the NAPL FLUTe cover to map both the NAPL and the distribution of the dissolved phase. See the FACT description for that mechanism for obtaining a replica of the dissolved phase distribution.

The NAPL FLUTe responds quickly to the contact with NAPL. See the video below “How the color reactive liner maps contaminates.”

The NAPL FLUTe systems are more commonly installed in open stable boreholes by eversion. Another procedure for installation through direct push rods has been long in use (see the video above “NAPL FLUTe system”). Both methods can include the FACT. If the NAPL FLUTe cover alone is installed on a blank liner, the residence time in the borehole can range from an hour to a day. A longer exposure is not necessary. However, the FACT method requires a 1.5-2 week residence in the borehole. If the NAPL FLUTe and FACT are combined, the longer exposure is best.

The installation procedure in an open borehole is described in the document,
NAPL Blank install in open hole and in the video available from FLUTe on the blank liner installation and removal procedure. The NAPL FLUTe liner is installed with a pump tube which is not used with the ordinary blank liner. The pump tube allows the liner to be everted to the bottom of the borehole even in a relatively impermeable formation. The FACT installation may not use a pump tube to allow better isolation of the carbon felt.

The blank liner with the NAPL cover is removed from the borehole by inversion as is an ordinary blank liner. At the surface, the cover is inside the inverted liner. The procedure for removal of the cover from inside the inverted liner is described in the publication
NAPL FLUTe procedure.

The inverted cover can be placed next to a tape measure to allow the stains to be photographed with the indicated depth in the borehole. The cover can be rolled for storage, but the stains may fade with long exposure. The dye stains are more durable. The oil-on-paper like stains will disappear. Some of the common stains are shown in the photos on this page.

How the color reactive liner maps contaminates


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TCE plus stains Rome GA

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Xylene stain Stanlow UK

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TCE stains Denver CO