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November 2017

In This Issue:

City of London relies on strength and durability of Geotube® containers for award-winning ash dewatering solution

After dewatering thousands of tonnes of ash, using dozens of Geotube® containers, the Greenway Wastewater Treatment Plant (WWTP) in London, Ontario reports that the five-year-old system continues to “exceed expectations” for reliability and performance.

“We selected Geotube® containers for our ash dewatering system for their strength and durability,” says Mark Elliott, Senior Engineering Technologist with the City of London.
“Each unit is built using a sturdy fabric and seam design that allows the bags to be pumped to higher maximum heights. This was an important consideration for us from the outset of the project because it meant that Geotube® containers would enable us to maximize our dewatering process in the smallest footprint possible.”

Sludge from the Greenway WWTP, along with sludge from five other plants is incinerated at the site, producing ash that is sent to storage lagoons. As the City grew and sludge volumes increased, plant managers began exploring new technologies to simplify handling and disposal of the ash. Bishop Water’s award-winning Geotube® dewatering system not only achieves this, it also eliminates the need to expand the storage lagoons.

The innovative ash dewatering facility occupies an area of only 1,200m3 – significantly less space than adding two more storage lagoons, which would have been three times larger at approximately 4,600 m3.

Geotube® system exceeds expectations

“We started with a test pilot using Geotube® containers in 2011,” Elliott says. “The initial results were great so we decided to install a full-scale Geotube® dewatering system.
The performance of the system has not only met our expectations, it’s exceeded them. We’ve continued to use the Geotube® containers because they’re reliable, easy-to-maintain and consistently produce high-quality filtrate.”

The high strength, woven polyethylene fabric in Geotube® containers, along with a polymer specifically selected for the site, provides exceptional solids retention and helps achieve a strong dewatering performance. Currently, it takes about two months to fill two Geotube® containers, which can hold 900 tonnes of ash combined. Once they’re filled, it takes about 100 trucks to transport the dry solids from the Greenway WWTP to a landfill. At its maximum capacity, the laydown area can handle seven 18 m x 13 m Geotube® containers simultaneously.

“Our experience working with Bishop Water has been excellent,” Elliott says. “The staff are great to deal with and they’ve continued to check in with us 2 to 3 times a year to see how the Geotube® bags are functioning. Given the opportunity, I would work with Bishop WaterTechnologies again without a doubt.”

Click here for more information about the advantages of using the Geotube® dewatering system at the Greenway WWTP.

Click here to learn more about using Bishop Water’s Geotube® containers and dewatering system for municipal applications.

Contact us to discuss dewatering options for your WWTP.

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New pressurized dewatering test key to optimizing large-scale Geotube® applications

A new pressurized dewatering test is among the latest assessment tools used by Bishop Water Technologies to accurately model large-scale Geotube® dewatering performance. The Pressure-Gravity Dewatering Test (P-GDT) simulates pumping pressure to fill a Geotube® container and provides a more accurate picture of full-scale Geotube® dewatering performance of chemically conditioned sludge.

Data gathered from the test also aids the Bishop Water team in the design, equipment selection and construction of complete Geotube® dewatering systems for municipal, industrial and agricultural applications.

A P-GDT test can be performed onsite, or in the Bishop Water laboratories, and requires a 55-gallon sample to measure several important parameters to design the full-scale system including the:

  • Volume and rate of filtrate released from the material;
  • Quality of filtrate;
  • Time needed to achieve a specific percent total solids (dry weight);
  • Quantity and size of Geotube® containers.
“The P-GDT expands our range of onsite and in-lab tests to verify the effectiveness of a polymer in a full-scale application,” says Keith Galloway, Wastewater Treatment Specialist with Bishop Water. “Our team has a fully equipped lab where we can test sludge and develop a detailed dewatering report that outlines the results of the testing. We also have the experience and know-how to assist with understanding the data and using it to calculate the savings in energy, chemicals and hauling.”

Undertaking a P-GDT test enables the Bishop Water team to select the best possible polymer and optimize the dose rate, which in turn helps to achieve the highest dewatering using the least amount of polymer. Bishop Water also includes a highly efficient, automated polymer dosing system with each Geotube® dewatering system. Operators can precisely control the polymer dose using the Venturi Emulsified Polymer Activation System (VEPAS) which requires very little maintenance. Unlike conventional polymer systems, which can take hours to clean, the VEPAS can be cleaned in about 30 minutes after use.

“Bench-scale testing plays an important part in developing an effective Geotube® dewatering system,” Galloway says. “Once the testing is complete, our team can manage all aspects of a project including system design, installation, operation and monitoring.”  

Click here for more information about P-GDT.

Click here for more information about the advantages of a Geotube® dewatering system for your municipal, industrial or agricultural operation.

Contact us to arrange a test of your material.

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Not all geotextile containers are created equally – How to spot the differences

Geotextile containers might all look the same to many people, but understanding the differences between Geotube® containers and others is critical to maximize performance and avoid disastrous failures. Geotube® containers are a proven solution for a variety of applications, including dewatering of sludge and soil as well as shoreline protection. The construction, material, and weave pattern contribute to the durability and performance of Geotube® containers in these applications.

Despite the simple operation and appearance, Geotube® containers employ state-of-the-art technology and engineering to produce a proven, reliable containment and dewatering solution. Here’s how Geotube® containers are different:
  • Circumferential seams for maximum strength: Geotube® containers are constructed using circumferential seams which relocates the weakest link to an area where there is lower stress. Others don’t do this. Instead, conventional geotextile tubes are sewn in the longitudinal direction along the weakest links resulting in more stress and increased risk of rupture. With a more stable foundation, Geotube® containers can be filled to taller heights, greater widths and handle higher volumes of sludge.  
  • UV resistance to withstand exposure: Exposure to UV irradiance degrades the appearance, material density and performance of geotextile tubes when they are used as a long-term dewatering solution. Geotube® containers are protected with UV inhibitors to prevent damage and ensure that they provide meet performance requirements for the duration of their use. For more demanding applications such as shoreline protection, a Geotube® container can be reinforced with a debris shield or polyurea coating.
  • Optimized weave for dewatering and solids retention: An optimal weave pattern is an important consideration for building a strong container and achieving a strong dewatering performance. Using a monofilament and fibrillated tape construction has been proven to achieve the best dewatering performance through testing by Tencate, the manufacturer of Geotube® containers. Bishop Water uses the Geotube® GT500 container, which has been designed using this weave pattern to provide exceptional solids retention, for a variety of dewatering applications. Alternative geotextile tubes, like the Geotube® GT1000 container, are available for long-term applications such as shoreline protection.
Geotube® containers can be adapted for a wide variety of conditions and customized for the needs of each project.
For example, Geotube® containers have been used as a long-term dewatering solution at sites with varying sludge conditions, which require careful polymer control to maximize dewatering performance. In all cases, Bishop Water staff work with the client to select the best polymer and ensure that the correct dosage is being used on an ongoing basis.

Let Bishop Water expert team assist with all aspects of your project, including design, installation, polymer selection and dosing, and training.

Read our case study to see how Geotube® containers have been used as part of a long-term dewatering solution at the North Rustico Wastewater Treatment Plant.

Learn more about how Geotube® containers can be used for solids dewatering.

Contact us to discuss your dewatering needs.

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Latornell Conservation Symposium
November 23, 2017
Nottawasaga Inn and Conference Centre
Alliston, Ontario
Attend our Presentation:
High Strength Geosynthetics as a Low-Cost Erosion Protection Solution
Robin Wakelin, Bishop Water Technologies
Session TH1D: Holding the Line – Tools for Managing Landscape Erosion

Visit our website for more information on upcoming events and projects.

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Visit our website to read more about Geotube® containers.

Contact us to discuss Geotube® units for your site.

Pilot Projects:

Evaluate and validate the suitability of our innovative treatment solutions for your needs.

Bishop Water Technologies can handle every aspect of pilot project setup, monitoring and analysis to ensure optimum technology selection and design for your full-scale application.

Contact us to discuss pilot project options for your site.




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Contact Us:

Bishop Water Technologies
220 Carswell St.
Renfrew, Ontario 
K7V 2G4

T:(343) 361-0463
F: (844) 272-6102
Copyright © 2017 Bishop Water Technologies Inc., All rights reserved.

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