Geotube® Dewatering Technology
The Low Cost, High Volume Dewatering Solution
Geotube® dewatering technology has become the dewatering method of choice for organizations around the world. Geotube® dewatering technology is used for projects large and small, and there is good reason -- simplicity and low cost.
There are no belts, gears, or complicated mechanics. Geotube® containers are constructed of high-strength, permeable, specially engineered textiles designed for containment and dewatering of high moisture content sludge and sediment. They are available in a variety of sizes, depending on your volume and space requirements. Geotube® systems can even be mounted in mobile roll-off containers that can be transported around your property as necessary. It's one of the most versatile dewatering technologies available.
And one of the most effective. Volume reduction can be as much as 90%, with high solid levels that make removal and disposal easy. Our dewatering technology also allows for profitable recovery of valuable solids.
HighlightsCustom fabricated with seaming techniques that withstand pressure during pumping operations.
High flow rate allows residual materials to dewater, while containing solids.
TenCate™ pioneered the dewatering technology.
We have spent years perfecting the technology and hold several patents.
With our vertically integrated manufacturing approach, TenCate™ controls all aspects of product quality.
All of our facilities are ISO-9001-2000 Certified.
Our testing laboratories are the only A2LA and GRI-LAP certified labs within the geotextile industry, and they are re-certified yearly.
Geotube® systems have been in place since 1962.
Over 2,000 dewatering projects have used Geotube® units.
TenCate™ has partnered with federal agencies to develop and advance the technology.
Dewatering OverviewMillions of gallons of sludge have been pumped into Geotube® containers for containment and dewatering of industrial waste, municipal sludge, and hazardous contaminated sediments. Paper mills, chemical companies, industrial plants, and nuclear power plants are just a few of the clients that have benefited from Geotube® dewatering technology.
Geotube® dewatering technology is the low cost, high volume dewatering solution. The dewatering process is simple and effective.
Key Benefits of Geotube Dewatering Technology
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Effective high volume containment
Efficient dewatering and volume reduction
Cost effective
No special equipment required
Project Implementation Steps
Testing and Evaluation
Software Analysis
Pilot-Scale Project
How It Works
Geotube® dewatering technology is the low cost, high volume dewatering solution. The dewatering process is simple and effective. The pumping process is repeated until the tube is full. Eventually, the solids can be handled as dry material, increasing options for transportation and disposal.
How Geotube® Dewatering Technology WorksDewatering with Geotube® technology is a three-step process:
Step 1: Filling -- Sludge (dredged material) is pumped into the Geotube® container. Environmentally-safe polymers are added to the sludge, which makes the solids bind together and water separate. The Geotube®container's unique fabric confines the fine grains of the material.
Step 2: Dewatering -- Clear effluent water simply drains from the Geotube® container through the small pores in the specially engineered textile. This results in effective dewatering and efficient volume reduction of the contained materials. And this volume reduction allows for the repeated filling of the Geotube® container. Over 99% of solids are captured, and clear filtrate can be collected and recirculated through the system. The decanted water is often of a quality that can be reused/returned for processing or returned to native waterways without additional treatment.
Step 3: Consolidation -- After the final cycle of filling and dewatering, the solids remain in the bag and continue to densify due to desiccation as residual water vapor escapes through the fabric. Volume reduction can be as high as 90 percent. When full, the Geotube® container and contents can be deposited at a landfill, remain on-site, or the solids can be removed and land-applied when appropriate.
Installation of Geotube® ContainersHere a brief summary of our step-by-step installation of Geotube® containers.
Step 1: Grade the site to remove any debris or sharp objects. (It is important to avoid puncturing the impermeable membrane or the Geotube® unit.) Be sure to level site from side to side, with no more than a 0.5% grade from end to end.
Step 2: Construct a containment berm 1/3 to 2/3 the height of the Geotube® unit around the perimeter.
Step 3: Dig trench inside containment berm, sloped for positive drainage to lower end of cell.
Step 4: Place impermeable membrane over the entire dewatering cell including the interior trench and the perimeter berm.
Step 5: Place drainage media (such as free-draining granular material or drainage net) over the entire site, except for the interior trench and containment berm.
Step 6: Unroll Geotube® unit over the drainage media on the upper end of the dewatering cell. Align unit using the handling straps.
Step 7: Install an inline mixing manifold system which includes an injection port, 90-degree elbows for mixing, and a sample port. Pump sludge through the return line as a final floc check before pumping into the Geotube® unit.
Step 8: Connect a flexible line to the filling port. Pinch valves are the preferred method to control the waste stream.
Step 9: The circumference of the Geotube® unit determines the design pump height. DO NOT exceed the design fill height.
Step 10: The Geotube® unit can be filled multiple times during the dewatering process. [Note: In colder climates, the freeze-thaw cycle improves dewatering efficiency.]
Step 11: Simply cut open the container and remove the solid material.
Use of Chemicals to Optimize the Dewatering Process
Chemical use is encouraged to enhance the dewatering process in most applications. Chemicals include: (1) coagulants and (2) flocculants. The right chemistry is critical. This should be the first step of the process. Professional counsel is strongly recommended to enhance performance.
The right chemical conditioning improves the following:
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The rate of dewatering
Retention of suspended solids and contaminants
Clarity of effluent in NTUs (Nephelometric Turbidity Units)
Percentage of dry solids
Overall utility of Geotube® unit
The proper dosing and use of chemicals should be a priority in the preliminary planning of a dewatering project. Please see our
Chemical Conditioning section for further details.
Chemical ConditioningChemical Conditioning refers to the addition of coagulants and/or flocculants to optimize the sludge dewatering. The following is a layman's description for chemical conditioning to provide a general understanding of the steps involved in setting up a system to make the chemicals down into solution and them mix the solution into the sludge or slurry prior to it going into the Geotube® unit for dewatering.
We recommend that you consult with a professional polymer supplier to conduct the bench tests to determine the optimum products and dosages. Likewise, if you are not familiar with setting up the polymer mixing and injection system, consult with your polymer supplier for assistance. A simple polymer make down system used to mix chemicals into a dewatering project.
For all kinds of dewatering equipment, be sure to check all of these parameters:
Sludge flow
Sludge concentration
Flocculant flow
Flocculant concentration
Post-dilution water flow
Injection point(s)
TenCate Geotube® has developed two tests to assist the operator or chemical supplier in evaluating candidate chemical regimens: (1)
RDT (Rapid Dewatering Test) and (2)
GDT (Geotube® Dewatering Test).
These tests allow the operator to do the following:
Visualize the dewatering process
Evaluate the efficiency of the selected polymer
Analyze the clarity of the effluent
Predict achievable percent solids after dewatering in Geotube® units
Estimate the time of the dewatering cycle.
Flow Diagram for Polymer Make Down System
This diagram illustrates a simple polymer make down system used to mix chemicals into a dewatering project. This shall serve as a general illustration. TenCate™ recommends you consult with your polymer supplier for assistance in setting up your polymer mixing and injection system.
Pilot-Scale TestAnother option to consider is a Pilot-Scale Test. Smaller Geotube® units can simulate operational conditions when space, time, and/or budget considerations apply. Larger scale pilot tests can also be used (if space and budget allow) to provide very detailed information. Large or small, pilot testing provides information, education, and measurable results in a very cost effective manner.
Software Analysis
TenCate™ provides design and technical assistance to owners, engineers, contractors, and customers to insure that each and every Geotube® project is successful for the customer.
TenCate™ offers support for all Geotube® projects with four proprietary software programs: Geotube® Simulator, Geotube® Estimator, Geotube® Illustrator, and Geotube® Stacking Analyzer. These programs provide preliminary output data to insure proper groundwork for dewatering (and shoreline protection) projects. All of the Geotube® software programs have both Metric and English input and output capabilities. Sample outputs are shown at the right.
Geotube® Simulator software provides the dimensions, stresses, and fill volumes for specific circumferences and heights of Geotube® units. This program creates a scale dimensional cross section image for any given Geotube® circumference and height.
Geotube® Estimator software calculates the length of the Geotube® units required for any dewatering project where the volume or known flow are provided. Dewatered volumes, number of pumping days, and dry tons are also part of the output data.
Geotube® Illustrator software looks at the defined footprint of a project and combines it with the volume of material to be dewatered. Then it calculates the number of Geotube® units needed, number of stacked layers, and amount of filtration fabric required to complete the project.
Geotube® Stacking Analyzer software identifies the maximum stresses on the Geotube® units at the critical locations for a variety of the stacking alternatives.
Safety in Selection & Operations
Introduction
Always follow the safety rules of the project or site owner, contractors, and regulatory agencies such as: OSHA and EPA. This safety section addreses safety recommendations for working with Geotube® containers.
Safety Considerations
There are many safety considerations involved in the selection and operation of a Geotube® unit. These include: fabric strength, capacity, seaming issues, and port design.
Additional Safety Information
Check out the other web pages in this Safety section and read more about these additional safety issues:
General Safety Issues1. Follow all site preparation recommendations as provided by your
TenCate™ Market Manager.
2. The surface that the Geotube® container is placed on must be clear of any sharp objects that could pierce the units when filled and under pressure.
3. The Geotube® container area should have limited access with all individuals being briefed on the recommended safety instructions.
4. Geotube® containers and surrounding areas may be slippery due to (1) filtrate coming through fabric, and (2) possible surface deposits due to filtration.
5. Many installations contain contaminated material. Check with site personnel for proper safety requirements when around Geotube® containers, filtrate, and sludge.
Geotube® Container Handling1. Unload Geotube® containers using rigging slings rated for proper Geotube® weights. DO NOT use forks.
2. Store Geotube® containers on-site in a secure location out of traffic flow areas.
3. Position Geotube® unit on flat, level surface within the dewatering cell using the unrolling straps contained in the Geotube® package
Filling and Working Around Units
1. DO NOT fill Geotube® units over the manufacturer's maximum fill height stenciled on all Geotube® units (next to the fill ports.)
2. Always wear safety equipment specified by OSHA, property owner, and contractor.
3. DO NOT wear footwear that has cleats, spikes, or sharp objects on the soles.
Access and Working on Top of Geotube® Container
1. Geotube® containers that are filled, or are dewatering, may be wet and slippery. Caution is advised.
2. There are several safe ways to get on top of Geotube® containers.
3. Geoport® cover plates should remain in place when ports are not being filled.
4. Extra precaution is needed near ends and sides of units that are sloped.
5. Proper care should be taken when working on top of units or moving from one unit to the next.
Unplanned Release of SolidsThis involves releases such as when a puncture, hole, or rupture occurs.
1. Ensure all personnel are present and accounted for.
2. If solids are on any personnel, follow site cleaning requirements based on the type of solids.
3. Contain escaped solids. If large volume is present, place absorbent material (such as hay bails) around and over the released solids.
4. Notify appropriate personnel as required by site and regulator personnel.
5. Repair if needed.
Removal of Solids
1. In area where removal equipment is operating, ensure that it is appropriately marked.
2. Depending on the type of solids being removed, special precautions may be required.
Geotube® Dewatering ApplicationsGeotube® dewatering technology delivers solutions that offer high strength geotextiles with very unique filtration and retention properties. From our complete product line for the Dewatering Market, we offer materials that provide solutions for the following applications:
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Mining & Mineral Processing
Flexible Enough for Available Space
Geotube® industrial fabrics deliver solutions for mining and mineral processing. From our complete product line for the dewatering market, we offer materials that are ideal for handling dewatering and containment in one operation. Mine tailings, coal sludge, and other materials can be managed and handled cost-effectively with Geotube® dewatering technology. Because Geotube® containers can be custom-sized to the application, they can be placed in available space between other structures, and removed once dewatering is complete. Geotube® dewatering technology is a cost-effective alternative to mechanical processes. It reduces disposal cost by consolidating higher solids with very little maintenance.
Effluent can be pumped directly from the process; or if a clarifier/thickener is used, effluent from the underflow can be diverted through the Geotube® container, eliminating the requirement for an expensive mechanical dewatering device. Geotube® units can be used to capture fines, silts, and clays from the tailings effluent prior to discharge into the ponds or directly into streams. Geotube® units will separate and dewater the fines and allow disposal without expensive dredging and transporting operations. In some cases, conditioners or polymers are used to promote flocculation to improve solids retention and filtrate quality. These solids can be safely stored onsite between uses or can be disposed of in a landfill. Because contaminates are contained, Geotube® dewatering technology eliminates concerns associated with airborne pollutants.
Geotube® containers can also be used to utilize the fines to build dikes and containment berms.
Source :
http://www.tencate.com/
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