Product Lines

Geotextiles  GMT, Inc. has two unique geotextile products which serve different segments of the market: • High strength/puncture resistant "landfill liner" - not a membrane but a layer to be placed on top of the membrane that lines a landfill. Made from a blend of synthetic fiber and coarse stainless steel fibers, this material forms a thick (1/2" or more if desired) puncture barrier over the membrane along with creating a porous laminar flow zone right against the membrane. Water and leachate, pulled down by gravity, flows through the laminar flow zone into the collection system at the bottom of the landfill, as intended by their design. This eliminates areas where liquids pool or collect but can't flow down due to the fill mass preventing it from flowing downward or along the membrane. Optional addition of a mild steel fiber into the blend would also make the matrix a rich source of high surface area iron. This iron could treat a large number of different leachate contaminants "in situ" before ever reaching the landfill drain by utilizing "Zero Valent Iron" (ZVI) contaminant immobilization reactions. ZVI is explained in more detail below. The matrix also maintains a void space that can be used to vent off gasses if proper means to do so are employed at the margins of the matrix. Those landfill effluent gasses that are heavier than air migrate downwards in a landfill and can be vented off by pumping a partial vacuum on the matrix. Basically, the combination of coarse poly fibers and highly resilient stainless steel fibers creates a textile with a very high resistance to collapse, ensuring porosity even under very high compressive loading forces. The uneven nature of landfill waste further ensures a contiguous porous layer, even where there are point sources of extremely high compressive forces (likely puncture points of membrane). GMT’s matrix spreads these forces over a greater area while preventing the "point" from penetrating through to the membrane (liner). • As a permeable reactive barrier (PRB) material. Impermeable and permeable geotextiles are already in use in PRB systems. Impermeable geotextiles are used in remediation installations to direct groundwater flow and prevent flow in unwanted directions. Permeable geotextiles are used to keep layers of an installation distinct and to prevent fines and precipitated contaminants from migrating in unwanted ways. Using mild steel and synthetic and/or stainless steel fibers, the GMT geotextile becomes a chemically active component of the PRB system. In some cases, the whole installation may simply involve digging a deep narrow trench; lining the trench with the GMT reactive geotextile as the single component PRB; and refilling the trench. Also, since the zero valent reaction is an immobilization technique, the contaminant will be trapped (immobilized) in the textile. After some length of time, the GMT PRB Geotextile could be removed or replaced such that the textile and perhaps a thin layer of earth surrounding it is all that needs to be treated as contaminated waste. • Zero Valent Iron reactions are a well known mechanism of chemistry wherein Iron (Fe) reacts with soluble forms of many unwanted compounds and immobilizes them as insoluble byproducts attached to the iron matrix. The most common commercial uses for ZVI have been in treating groundwater for Phosphorous and Arsenic contamination. However, it is known that ZVI is also effective in immobilizing hexavalent chromium, mercury, chlorinated hydrocarbons and many other toxic compounds. Steel wool, made from mild (low carbon) steel wire, is a rich source of iron ions, being comprised of >98% iron by weight as well as being very finely divided, providing large surface area-to-weight ratios. At the same time, steel wool is superior to powder forms of iron, which are high in specific surface area but are prone to agglomeration, migration, excessive oxidation and are not conducive to simple or versatile installations. Iron rich geotextiles are an untapped potential market and GMT welcomes inquiries for joint development, academic study, test installations and other technology validation proposals.

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