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MQA and GRI specs

February 1, 2016

There is much inconsistency regarding the definition of a production batch quantity for geomembranes and how this relates to MQA sampling frequencies. What is the intent of the GRI specifications? Maggie | Australia Maggie, Regarding MQC—the factory production of like material—the GRI specifications give the frequencies of each particular test. These values were the subject …

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LLDPE Question

“Burnout” occurred when the double-seam fusion welder got stuck as it welded (a stop at a small crease or at times going up a slope) followed by the welder sitting in one spot for a short time causing a burn hole in the LLDPE. The welder continues from that point onward once the situation is …

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Breathable membrane

I am a graduate student pursuing a Ph.D. in environmental engineering. My project involves solving sanitation issues of urban slums in India using breathable membranes. We use a 55-gallon drum lined with this breathable membrane to serve as collection and storage for the fecal matter. We have been pursuing modifications on the project design and …

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Conductive geomembrane

We are developing a conductive liner. I want to know if there is any kind of small-scale test that I can apply in our laboratory as a quality control test. Pacqua | Mexico Pacqua, Great to hear from you and nice to know that you are developing a conductive GM. What is typically done in …

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Exposed geomembrane cover

I am evaluating the feasibility of constructing an exposed geomembrane cover on a coal combustion residuals (CCR) fly ash impoundment. The evaluation includes scenarios of: (1) allowing surface water to shed and (2) intentionally impounding water. In reviewing the available literature, I came across your article “Traditional vs. exposed geomembrane landfill covers” (Geosynthetics, October/November 2012). …

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Spray over HDPE?

Is it possible to spray over an HDPE liner? Can you provide me with spray manufacturers? Abbey | Saudi Arabia Abbey, There is no need to spray on HDPE, and even if you did it wouldn’t stick very easily. Regarding spray manufacturers, just Google “spray applied membranes” and you will get information in this regard. …

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Geocomposite drainage layers

October 1, 2015

Flammability? Zip ties? MARV? Ponds? GT specs? Questions and answers from the GMA Techline. I wonder about your opinion on the use of a triplanar geocomposite for landfill drainage layer. We have not approved these in our jurisdiction to date. I have a current application where this is proposed to be used (vertical expansion). I …

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Saturated soil cover on liner question

Questions and answers from the GMA Techline. I need your advice on a reservoir we are designing. It is an irrigation reservoir with a 40-mil HDPE geomembrane liner on a 3:1 slope. The client wants to cover the liner with 1ft of silt loam soil. The water elevation in the reservoir will fluctuate about 15ft …

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Geotextile data

Flammability? Zip ties? MARV? Ponds? GT specs? Questions and answers from the GMA Techline. I am a student of hydraulic structures and I need some data about transmissivity of geotextiles (ASTM D4716 or ISO/DIS 12958); and also permittivity or cross-plane permeability (ASTM D5493 or every valid standard). My thesis is about transmissivity and permittivity of …

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Protrusion/particle shape—geotextile cushions

Flammability? Zip ties? MARV? Ponds? GT specs? Questions and answers from the GMT Techline. Our landfill liner project specifications require the use of rounded to subangular gravel to be placed as a leachate drainage layer or leachate collection pipe bedding. The gravel is separated from the geomembrane liner by a nonwoven geotextile cushion. During bidding, …