 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
NAPL FLUTe™
The NAPL FLUTe system addresses the problem of locating layers, filled fractures or globules of pure product trapped in the formation. The approach is to emplace in a punched or drilled hole, a fabric that reacts with the NAPL to produce a very obvious stain on the fabric where it contacts the pure product. The fabric (also called a cover when emplaced on a liner) is recovered by inverting the liner from the hole.
This peeling process inverts the cover and liner to allow the cover to be removed without touching the hole wall at any other place than the original placement. The emplacement methods range from installation in the interior of a push rod (e.g., a cone penetrometer or Geoprobe) to everting the liner with the outer reactive cover into a core hole. Both techniques allow the cover to be emplaced against the hole wall without contact with any other portion of the hole wall. When the liner and reactive cover are in place, they are as shown in the drawing. The excess head in the liner above the water table in the formation forces the liner strongly against the cover and against the hole wall. After the cover has reacted with the formation fluids, the tubing is lifted upwards, inverting the bottom end of the liner with the covering. As the tubing is pulled from the hole, the inverting liner follows it to the surface. After the entire liner/cover is peeled from the hole, the liner is pulled off the covering, exposing the inside surface of the cover. The stains on the inside surface are easily read for the location of the NAPL in the hole.
The NAPL FLUTe installation via the interior of the push rods is shown in the stepwise drawing of the procedure (shown below). The essential feature of the method is that the liner dilates to support the hole wall, but it does not dilate inside of the rod. If it did, the friction is so large as to tear the liner as the rod is withdrawn. As it works, the liner expands against the hole wall as the rod exposes the wall. In that way, the reactive cover is pressed again any NAPL in the pore space or fractures of the formation.
This technique was first used at Cape Canaveral to locate a thick layer of TCE in the coastal sediments. Since then, it has been used in many states to test for the presence of free product in the formation. Earlier versions of the reactive cover used Sudan IV. Sudan IV has been replaced with a nontoxic dye.
The patented method for emplacing such a large assembly of covering, liner and tube in the interior of the rod and removing it without damage is unique to this system. The reactive cover is covered by another patent pending. Research is in progress for perfection of other reactive coverings to detect other kinds of compounds in the subsurface. Contact us at
for the most up to date procedure for this installation.
The installation into cored holes uses the technique for the everting liner installation very similar to that described in the everting liner method. In the unsaturated zone, the liner and covering are everted into the open hole from an air pressure canister. For installations into water filled holes, the liner is everted into the hole using the "JUST ADD WATER" technique. The results from a water driven eversion into a 3" core hole are displayed here.
TCE stains from fractures in a 3 in. core hole (note the boot toes for scale)
FAQ NAPL FLUTe (pdf)
Contact us at