A Geotextile Tube
By Industrial Fabrics, Inc ~ Since 1981
Frequently Asked Questions Page One
1. What are the greatest advantages of using an Envirotubes over mechanical dewatering?
• Turn a 90 day job into a 30 day job. (Mechanical processes are only 10% - 20% as efficient as Envirotubes)
• Envirotubes avoid shutting down the pumping process of the job.
• Envirotubes requires approximately 25% of the polymer as mechanical processes.
• Dewatering with Envirotubes is not affected by weather. Rain & weather does not affect dewatering and the material in the Envirotubes will not re-saturate. (Mechanical processes require the dewatered material to be protected or it will resaturate)
• Envirotubes avoid capital outlay and expensive equipment to rent or buy.
2. What to do about odors?
There is usually very little or any odor when using Envirotubes. Even when dewatering a very smelly organic material. Some chemical odor and cattle manure odor can be strong when using Envirotubes. There is often a visible gas release through the fabric but it is usually CO2 with little or no odor. The usual H2S odor associated with organic sediment is relieved by oxygen during the pumping process.
3. How does the Envirotube work?
The way the Envirotube works is when pumping into the tube begins the water will come out through the fabric and the solids remain. Eventually the fine grain materials will plug the fabric and the tube will pump up like a water balloon. Then, switch to the next tube. While the next tube is being pumped, the solids will drop out in the first tube and the filter cake will peel off the slippery fabric. The tube will then dewater rapidly .
4. How clean can I get the decant water?
Different states have their own specs on TSS that can be released to the environment. Any specification can usually be reached. This is especially important when dewatering contaminated materials or releasing to a fragile environment. To get very clean decant a second polymer is sometimes required. Also, special care needs to be taken at the initial fill of the tube to prevent flutter allowing solids to pass through the fabric. Many or most contaminates like PCBs, etc. will cling to the solids and stay in the tube, requiring little or no after treatment.
A polymer is usually needed and definitely speeds up the dewatering process, makes for clean decant water, and saves money on the Envirotubes. As the tubes and polymer work better with a wet slurry, it is very desirable to return the decant water to the pond.
5. Do I need a polymer?
6. How do I tell what polymer to use?
This is determined by testing the slurry with polymers to choose the right one. This can be done on site, or by the polymer MFGR in a lab.
7. How do I tell how much polymer to use?
When connecting the discharge line to the tubes allow for a sample port before the slurry enters the tube [a 2” ball valve works great]. This way the polymer feed can be adjusted for maximum efficiency, saving time and money.
