How a polymer dosing system can make or break your sludge dewatering process.

DATE POSTED: February 28, 2022


Polymer dosing systems for dewatering.

Polymer is the secret ingredient for maximizing dewatering and achieving high quality filtrate from the Geotube® containers in our Bishop Solids Management Solution. But selecting the right polymer is not enough to get the best results.

Precise dosing is critical to ensure that the operation runs smoothly and that dewatering occurs as required without any unfortunate incidents. Not enough polymer will result in poor dewatering performance, insufficient solids retention and low-quality filtrate. Too much polymer can clog the pores of the Geotube container and prevent water from being released. In such a case, the bag is no longer usable and could burst if operators fail to notice the problem and overfill the container.

VEPAS Polymer Dosing System
VEPAS Polymer Dosing System

Bishop Water’s VEPAS™ (Venturi Emulsion Polymer Activation System) is an easy-to-use and affordable system that mixes and fully activates liquid polymer emulsions in a single step, adds the precise dose directly into the sludge feed line and eliminates the need for messy mechanical mixers and bulky aging tanks.

Compact size, smart controls

VEPAS polymer dosing can be configured to monitor sludge flow and consistency using flow and mass meters, enabling it to automatically adjust polymer dose to achieve the optimum mix and dewatering properties. These smart controls also communicate with 4-20 mA inputs, which enables VEPAS to be integrated to the plant SCADA system and configured to automatically begin operating when sludge pumps are activated.

The compact, skid-mounted VEPAS occupies a fraction of the space of a conventional mechanical polymer system and can be quickly installed for new or retrofit applications in treatment plants, mobile trailers, or utility buildings.

Our Bishop Solids Management Solution with Geotube® dewatering technology and VEPAS is an integrated solution that can work with any wastewater treatment plant or industrial process to collect and dewater slurry materials. This enables any facility to build a compact, rapid dewatering solution that saves time, reduces operating costs, and simplifies sludge management.

A simple test can help us determine precise dosing of the polymer selected for your site and build a skid-mounted system that can be installed quickly. Once installed, our team can provide onsite training and are easily accessible to assist with ongoing maintenance and support.

Geotextile sludge management system provides long-term savings for North Rustico WWTF

Read a recent article that shows how our Bishop Solids Management Solution and VEPAS enabled the North Rustico WWTF to simplify sludge handling and significantly reduce operating costs.

Learn more about VEPAS.

Contact us to discuss a Bishop Solids Management Solution or VEPAS for your treatment plant.

Comparing carbon footprints: Geotube® containers vs. rocks for shoreline protection

DATE POSTED:


Geotube vs rocks for shoreline protection

Geotube® containers or rocks?

Which do you think offers a lower carbon footprint when constructing a breakwater structure?

Knowing the carbon footprint of your breakwater project can play an important role in fully understanding the environmental impacts of a project as well as the energy required for its construction; including extraction, manufacturing, transportation, installation, etc.

There are many options and variables to consider when building a breakwater structure and as a result, carbon footprints can differ dramatically. In each case though, our carbon calculator performs a detailed analysis of lifecycle carbon emissions and helps to quantify the environmental impact of each approach.

So, what’s the answer? It’s often Geotube®. Here’s an example that shows why.

This situation considers a 930-metre-long, 1.8-metre-high breakwater structure to protect a section of Lake Ontario shoreline.

Transportation makes the difference

To create a rock breakwater, the material would have to be transported by a convoy of trucks from a quarry that is about 160 km away. A conservative estimate for the amount of rock required is about 13,600 tonnes.

A breakwater structure made of Geotube® containers, however, could be filled with sand that is dredged from the lake at the construction site. This approach dramatically reduces truck traffic and could also reduce the time required and cost to complete the project. The proposed Geotube® system would require about 10,000 cubic metres of sand to fill the containers to the required height.

Once all the factors are considered, our carbon calculator shows that the breakwall constructed from Geotube® containers, using locally dredged sand, can be built with a significantly smaller carbon footprint.

Geotube Carbon Calculation - Shoreline System

And the winner is:

Geotube® breakwater carbon footprint: 175 tonnes CO2

Rock breakwater carbon footprint: 2,824 tonnes CO2

Result: The Geotube® breakwater project is lower in overall carbon emissions by 2,649 tonnes.

Download the detailed carbon footprint calculation.

Learn more about Geotube® Shoreline Protection.

Contact us to discuss your shoreline protection project and for a detailed carbon footprint calculation of a Geotube® breakwater structure vs. other approaches.

How to eliminate sewer surcharges with a simple, low-energy system

DATE POSTED: September 3, 2021


Pre-treatment of high-strength wastewater before discharging it to a municipal sewer can be challenging, especially if high levels of BOD, TSS and ammonia are present. But what if a simple, affordable, onsite solution was available to help meet pre-treatment requirements and avoid sewer surcharges?

Bishop Water combines two of its robust, easy-to-use treatment technologies—The Bishop Solids Management Solution and BioCord™ Reactors—to create a scalable solution for a wide range of industrial and commercial applications. The process can handle high solids and nutrient concentrations for a fraction of the capital and operating costs of more complex, energy-intensive alternatives.

How it works

Solids management and BioCord combined
Geotube dewatering

The wastewater first goes to Bishop Water’s Solids Management Solution. Unlike complex, energy-intensive mechanical dewatering equipment, the Bishop approach utilizes a passive dewatering process that achieves a high level of dry solids using only specially selected polymers, Geotube® filtration and gravity.

As the solids are pumped to the Geotubes, a polymer is added to retain non-soluble BOD, TSS, and other contaminants. The Geotubes also provide filtration and release clear water that is low in TSS, but may still contains soluble organics and nutrients.

This nutrient-rich filtrate is then transferred to a BioCord Reactor system for further treatment. BioCord Reactors provide a simple, robust process to remove soluble BOD and ammonia with very little operator oversight.

BioCord installation

A BioCord Reactor is simply a modular frame that supports densely arranged strands of polymer fibres. These fibres provide a massive surface area for the growth of aerobic and anaerobic microorganisms that are ideal for enhanced biological treatment and maintaining regulatory compliance – even in cold weather conditions.

This integrated solution can be customized meet the specific size constraints, treatment requirements, and growth plans for each site. The system also incorporates a modular design that can be easily expanded as treatment needs change.

Learn more about Bishop Water’s solids management and nutrient removal solutions.

Contact us to discuss treatment options for your facility.

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Bishop Solids Management Solution — Dewatering for all occasions

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We’ve dewatered a lot of stuff over the years.

Everything from ordinary wastewater sludge and excess soil from construction sites, to noxious slurries containing really smelly organics, industrial process wastewater, and even low-level radioactive materials. 

Over that time, we’ve learned a couple of things.

First, that our Bishop Solids Management Solution is extremely versatile. It can be used to collect, dewater and consolidate almost any type of slurry material. 

The second thing is that our Solids Management Solution is one of the most efficient and cost-effective ways to get the job done. Our passive, gravity-based dewatering system is often compared against more complex, energy-intensive processes such as centrifuges, belt presses, and filter presses. In most cases, we can demonstrate that the Bishop Solids Management Solution can achieve similar or better dewatering performance at a lower cost and using less energy than alternatives. 

The Bishop Solids Management Solution not only retains and consolidates solids, it also provides water treatment—greatly reducing TSS, nutrients and other contaminants of concern. This can be an effective pretreatment step or, depending on regulatory requirements, the filtrate can meet standards for discharge to the environment or even reuse in non-potable applications. 

Start with a simple sludge test

polymer selection

Our process starts by obtaining a sample of the sludge and performing a dewatering test. The test reveals a lot of important information such as the solids concentration of the slurry, the polymer that will provide the best dewatering performance and how much water can potentially be removed. 

We also need to know the approximate volume of sludge to be dewatered. This information, combined with the results from the dewatering test enables our team to calculate the number of Geotube® dewatering containers that will be needed, how large the dewatering cell will be, how much polymer will be needed and of course, how long the project will take. 

What’s your solids management or dewatering challenge?

We have the solution.


Contact us to discuss your solids management needs and learn how simple, low-energy solutions from Bishop Water can help. 

Learn more about the Bishop Solids Management Solution. 

Simplifying arsenic sludge management at a gold mine

DATE POSTED: August 19, 2021


Arsenic sludge management

Arsenic-laden groundwater continually infiltrates the shafts of a gold mine in Western Canada. As it’s pumped out, an onsite treatment system removes the arsenic to produce effluent that can be safely released. But the system also produces large volumes of sludge—about 1,900 litres every 45 minutes. The sludge was a challenge for the site’s existing media filtration system and a faster, more reliable and more cost-effective solution was needed. Learn how the Bishop Solids Management Solution provided a simple, low-energy solution that achieves dewatering, filtration and containment in a single step.

How long can a Geotube® shoreline protection system last?

DATE POSTED: July 2, 2021


Decades—even under some pretty tough conditions. Here’s an example. 


Nearly 25 years ago, Geotube® containers were installed at Atlantic City, New Jersey to protect more than a mile of shoreline and the famous boardwalk from storms and extreme high tides. The tubes were filled and covered with sand from the local area and planted with dune grass to give the appearance of a natural dune. 

But only three months after project completion, Hurricane Luis produced three days of storms and 10- to 12-foot waves that pounded the shoreline. Once it was over, residents could see that sand had been washed from the ocean side of the Geotube® containers, but on the other side, there was no damage to property or loss of shoreline. The local media called it, “a line in the sand… there will be no more erosion past that line.” 

Sand and vegetation was replaced and those same Geotube® containers have continued to protect the Atlantic City shoreline from storms, wind and waves. More severe weather in 2012, Super Storm Sandy, damaged the north end of the boardwalk, which was not protected by Geotube® containers, but the south end performed as designed and withstood the waves. 

Why are Geotube® containers so successful in Atlantic City? 

1. Massive size 

Each Geotube® container is a monolithic structure—100 feet long, 7 feet high and a circumference of 30 feet. The circumference can be as much as 50 feet, which gives engineers the flexibility to select the most appropriate size of Geotube® to withstand damaging forces from waves and ice. 

2. Durable Construction

Geotube® containers are made from high-tenacity polypropylene multifilament yarns, arranged in a stable weave. This material is highly resistant to UV, inert to biological degradation and resistant to chemicals, alkalis and acids. This material is also engineered to withstand scouring and punctures and can be reinforced for more demanding environments with a debris shield or polyurea coating.

Newly introduced Geotube® Durability Engineered Composites offer even more robustness and abrasion/damage resistance for shoreline projects. This advanced container incorporates a highly UV stabilized crimpled fiber that shields and cushions a woven geosynthetic underneath and also enables sand and soil entrapment so vegetation can easily be established. Watch our future e-news issues for more info. 

3. Stable structure

Engineers incorporated Geotube® containers into the natural structure of the sand dunes. Geotube® containers form the core of a more storm-resistant sand dune structure. Although the Geotube® containers may be uncovered during a storm, the help limit erosion primarily to the ocean-side area and can be easily covered up afterwards. 


Read more about the Geotube® shoreline protection project in Atlantic City. 

Learn more about the advantages of Geotube® containers for shoreline protection. 

Contact us to discuss your shoreline protection project. 


Watch our webinar to learn more about Geotube Shoreline Systems.

You will learn about:

  • Economic and environmental advantages of Geotube® solutions
  • Using Geotube® solutions for breakwalls, revetements, sand dune cores, wetlands restoration and more
  • Strength, versatility and customizability of Geotube® materials and products
  • Design and installation of Geotube® systems
  • Case studies from sites around the world

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Case study: Lagoon sludge removal provides affordable solution for algae and H2S issues

DATE POSTED: May 25, 2021


  • Lagoon sludge removal and dewatering
  • Bishop Solids Management Solution 
  • O’Leary Wastewater Treatment Facility, O’Leary, PEI, Canada

The challenge: Algae blooms and corrosive gases caused by sludge accumulation

Sludge accumulation was thought to be causing significant operational challenges for the O’Leary Wastewater Treatment Facility (WWTF), a two-cell lagoon system on the west side of Prince Edward
Island, commissioned in the 1990s. 

O’Leary’s treatment lagoon serves about 800 residents, several businesses and, for a period of time, was also receiving wastewater from a potato processing plant. 

Sludge maps are an important step in planning and executing lagoon cleanouts. WSP’s map of the O’Leary lagoon revealed significant accumulation.

The lagoons were experiencing serious blooms of blue-green algae during the summer months and exceedances of TSS, BOD and coliform bacteria in treated effluent. Hydrogen sulfide (H2S) gas, which was also attributed to the algae and sludge, was building up in a below-grade chamber that housed the plant’s UV disinfection system.   

Not only was the gas accumulation a hazard for operators, but it caused corrosion that damaged ductile iron pipes, an electrical panel and the plant’s UV system. 

Operators also saw “islands of sludge” periodically rise out of the water before bursting and releasing clouds of methane and H2S gases.

The solution: Dredging and passive dewatering meets regulatory and budget requirements 

In 2019, the Town of O’Leary began working with engineering consultants WSP to repair the damage to the UV system, alleviate the algae blooms and end the release of corrosive gases from the lagoon. 

WSP began with a comprehensive sludge survey, obtaining sludge depth measurements from several locations in each of the lagoons. 

The results revealed that despite their large area, the lagoons are relatively shallow, with a maximum depth of only 5 ft (1.5 m). Each cell had accumulated about 1.5 to 2 ft (0.45 to 0.6 m) of sludge, which significantly reduced their ability to remove nutrients and settle out solids. 

The team evaluated several options and awarded the project to AJL Contracting and Bishop Water Technologies to desludge the lagoon and dewater removed solids with the Bishop Solids Management Solution. This simple, low-energy system uses Geotube® containers, optimal polymers and gravity to collect, dewater and consolidate dredged sludge. 

Dredging the lagoon enabled it to remain in operation while sludge removal occurred and also complied with a provincial regulation that prohibits tracked heavy equipment from operating in lagoons with clay liners. 

The project began in the summer of 2020, with the construction of a lined laydown area designed to accommodate a layer of three Geotube containers 85 ft in circumference and 114 ft in length (26 x 34.7m) and a second layer of two 95 x 100 ft (29 x 30.5m) containers that would be laid on top. This stacking arrangement minimizes the footprint and cost of the dewatering cell. 

The results: No algae, no gases, no rush to haul away solids

Dredged sludge was first pumped through a 0.6 inch (15 mm) screen to remove debris, trash and improve the quality of the final dewatered biosolids for land application. 

From the screening plant, the sludge was pumped to the Geotube containers. Bishop Water’s VEPAS™ (Venturi Emulsion Polymer Activation System) added and mixed polymer directly in the feed line, eliminating the need for polymer aging and mix tanks. 

The Bishop Solids Management Solution accepts and dewaters solids as quickly as the dredge can pump, dramatically outperforming centrifuges or belt presses for speed and energy efficiency. Low-TSS filtrate released from the microscopic pores of the Geotube container was directed by gravity to cell two. 

Technicians continually monitored polymer performance and dose rates to ensure optimal dewatering and retention of contaminants. Daily sampling showed that the system was achieving about 20% solids
concentration after just a few hours of dewatering.  

The Bishop Solids Management Solution used a two-layer,  stacked arrangement of Geotube dewatering containers to  minimize the footprint and cost of the dewatering cell.

Desludging of cell one was completed in about four weeks. Two more weeks of sludge removal filled the first layer of Geotube containers to capacity and technicians stacked a new container on top of the others. 

One more week of dredging and pumping completed the project.  The total volume of wet sludge removed was 26,480 m3, which corresponds to 872 bone dry tonnes. 

A major advantage of Geotube containment is that the solids can remain at the site for months or even years, allowing ample time for the town to find a suitable location for land application and arrange funding for hauling. Throughout that time, passive dewatering will continue further consolidating the material. 

A seasonal freeze-thaw cycle also significantly improves dewatering, potentially elevating the solids concentration of the dredged material to 40% or more in this case. 

Since completing the project, operators report that there have been no issues with gas accumulation in the below-grade chamber or blue-green algae growth in the lagoons. 

Learn more about the Bishop Solids Management Solution for lagoon sludge cleanouts. 

Download the case study.

Contact us to discuss your sludge removal and solids management challenges. 

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Geotube shoreline system protects historic New Jersey lighthouse

DATE POSTED: January 27, 2021


Over the past several decades, the shoreline around the East Point Lighthouse has receded continually, posing a major threat to the more-than-170-year-old landmark. Despite the creation of a dune system designed to protect against erosion and rising sea levels, the ocean is nearly at the building’s doorstep. In March of 2018, a severe storm severely compromised the dune system forcing municipal work crews to hastily pile sandbags along the shoreline in front of the lighthouse. 

But a better solution with more longevity was needed. Later that year, the New Jersey Department of Environmental Protection began a project to install 600 feet of Tencate Geotube™ to reduce the risk of further erosion and help restore a natural, living shoreline.

Eight Geotube containers were laid end to end to cover the distance. Each was filled with sand and set on top of a scour apron held in place with anchor tubes. The scour apron is a critical part of the system, extending several feet beyond the Geotube to prevent wave action from compromising the shoreline under the structure. The lee side of the structure is further protected with Tencate sand filled mattresses, which are designed to remain exposed, endure abrasion and UV light, and also trap and hold soil on the surface to help establish a covering layer of vegetation. 

Unlike conventional sandbags, a Geotube container is massive. In this case, a sand-filled Geotube is five feet high, 10 feet wide and weighs more than 3,000 pounds. Once the Geotube is set in place, it’s virtually immovable and can withstand waves, wind, abrasion and impact. 

The new Geotube shoreline system was covered with sand to help create a coastal dune habitat, protect the inland wetlands from erosion and prevent the ocean from advancing further towards the historic lighthouse. 

Learn more about Geotube containers for shoreline protection.

Contact us  to discuss Geotube containers for your shoreline protection project. 

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More than a sandbag: Geotube® containers protect shorelines, restore beaches, create wetlands and more.

DATE POSTED: April 28, 2020


What does a beach restoration in the U.S., a jetty in Ecuador, and an underwater structure used in Germany to contain dredge spoils have in common? 

All are examples of Geotube® containers as a durable, reliable solution to diverse problems in land and marine management around the world.

Reliable shoreline protection under the toughest conditions

Protecting or reclaiming land, especially where weather cycles take their toll, can be an uphill, expensive and never-ending battle with conventional technologies. Worse, uncertainty is always a concern. Waves, heat, ice and debris can wreak havoc on structures built with earth, stone or concrete, shifting individual components over time and weakening the integrity of the structure.

Geotube® containers are a proven, cost-effective solution that not only protects shorelines from erosion, but rebuilds beaches and reclaims land from bodies of water for recreational, residential and industrial purposes. From dykes and groynes to beaches and wetlands, Geotube® containers have been customized to the diverse needs of clients world-wide.

In many cases, they can be installed for half the cost of armour stone or rip rap and will provide a stronger and more reliable structure. They can also be equipped with a high-impact Debris Shield for rough waters.  

Filling with local materials helps reduce costs and CO2 emissions 

One of the reasons for the lower cost of a Geotube shoreline system is because it can often be filled on site with a slurry mix of sand and water, introduced hydraulically into the units. This reduces transportation and installation costs and can significantly reduce the carbon footprint of a project.

The single, massive structure, can be installed on shore, or in deep water and is virtually immovable once in place. This provides an environmentally sound shoreline protection solution that can be covered with natural materials and restore shoreline or create wetlands habitat.

For more than 50 years, Geotube has protected shorelines, restored beaches and reclaimed land from bodies of water around the world, including in the U.S., Canada, Mexico, Ecuador, Germany, the Netherlands and Bahrain.

Let Bishop Water’s expert team assist with all aspects of your project, including design, obtaining the appropriate permits, site preparation and installation.


Learn more about Geotube containers for breakwaters, beach restoration, wetlands creation, jetty and groyne construction, marine or land containment and building underwater structures.

Contact us to discuss your shoreline protection or land reclamation project.

Why does freezing improve Geotube® dewatering performance?

DATE POSTED: February 27, 2020


Geotube containers that are filled late in the year are often left onsite over the winter to experience the dewatering advantages that the freeze-thaw cycle brings. Once the thawing begins, those previously frozen Geotube® containers can give up a lot of water—in some cases up to 50% of their volume.

This dramatic reduction in volume means that the containers can be topped up with additional slurry materials once they are fully thawed. Or, if the solids are destined for disposal, the reduced volume will mean much less material to transport and lower costs for hauling and tipping fees.

Expansion helps with consolidation of solids

Dewatering benefits from the freeze-thaw cycle because water expands as it freezes. The Bishop Solids Management Solution, with Geotube® containers, can attain 15 – 18% solids within a few days of dewatering, but that means there’s still a good amount of water remaining as cold temperatures set in. The formation of ice crystals and the expansion of the water compress the solids and once the thaw occurs, more water is released and the solids are further consolidated.

The results can be quite dramatic. At a recent wastewater lagoon desludging project, our crew filled Geotube® containers to a maximum height of 7.5 feet. The containers were left on site over the winter and after thawing in the spring, the height was reduced almost by half.

Some of our clients that are equipped with a permanent Bishop Solids Management Solution take full advantage of freeze-thaw cycles in their sludge management plans.

Geotextile sludge management system provides long-term savings for North Rustico WWTF

The North Rustico Wastewater Treatment Facility in Prince Edward Island, Canada uses several large Geotube® containers setup outdoors to dewater waste sludge, with a smaller container in a greenhouse that is used during the winter months. The outdoor containers are left to freeze over the winter and can be topped up in the spring once they thaw and release more water. This enables the plant to use Geotube containers for several seasons, replace them less often, and reduce operating costs.

Read the feature article about the North Rustico WWTF in Go With the Flow magazine published by the Atlantic Canada Water and Wastewater Association.


Learn more about Geotube® containers for solids dewatering.

 Contact us with your questions about the Geotube® freeze/thaw/consolidation cycle and to arrange for a dewatering test of your solids.