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.

PEI treatment plant simplifies batch sludge handling with VEPAS polymer system

DATE POSTED: July 30, 2019

Vepas System

A compact, non-mechanical polymer mixing system is making sludge dewatering easier and more efficient for the North Rustico Wastewater Treatment Facility (WWRF) in Prince Edward Island. Since its commissioning, in May 2014, the plant has relied on a Venturi Emulsified Liquid Polymer Activation System (VEPAS) to inject and activate polymer in a single pass with no mechanical agitation needed. 

The one-step, venturi-based VEPAS eliminates many of the components used in mechanical polymer systems, such as mixers and aging tanks. These components not only increase system size, but also require operator attention for maintenance and cleaning. VEPAS also enables operators to easily change the rate of polymer flow—a feature that is particularly important for the North Rustico WWRF, which processes highly variable sludge in batches for dewatering in Geotube® containers. 

Allan Nisbet, Operator, at the North Rustico WWRF says that waste sludge from the plant is pumped to a storage tank and dewatered in batches about every six to eight weeks. Since the composition of the sludge varies greatly from batch to batch, Allan always tests the sludge to determine the proper polymer dose rate before pumping sludge to the Geotube® dewatering containers. 

“The VEPAS is very simple to operate and provides precise control of the polymer dose, which helps maximize dewatering and reduce our polymer use,” Allan says. “Our system is equipped with an HMI operating panel where we can easily change and monitor the polymer dose rate.” Once the batch is complete, Allan says it takes only about an hour to completely disassemble, clean and reassemble all components – the polymer pump, lines and injector. 

“We’ve had great communication and support from Bishop Water, not only during plant commissioning, but on an ongoing basis,” Allan says. “The team recently suggested a new polymer for the dewatering process after reviewing one of our sludge tests. This new polymer should work better with our variable sludge and improve dewatering.” 

The VEPAS and Geotube® dewatering has enabled the North Rustico WWRF to become self-sufficient for sludge handling. Solids are dewatered, composted and distributed at the site as landscaping material, eliminating the need for hauling it away for treatment and disposal. 

Read more about how composted solids are used at North Rustico WWRF.

Learn more about the VEPAS 

Contact us to discuss a VEPAS for your treatment plant. 

Polymer Injection System Simplifies Mixing while Maximizing Dewatering

DATE POSTED: April 25, 2018

Bishop Water’s polymer injection system – the VEPAS – is specially designed and customizable to each project

Chemical costs can play a significant part in sludge handling, but a specialized polymer system form Bishop Water Technologies can help reduce chemical costs and dramatically simplify polymer mixing and handling. The Venturi Emulsified Polymer Activation System (VEPAS) is designed to fully activate liquid polymer emulsions in a single pass without the use of mechanical agitation or mix tanks.

This easy-to-operate, reliable polymer injection system, which functions with very few moving parts, not only saves space, but also helps minimize the damage to polymer molecules. Damaged polymer is less effective and requires a greater quantity to achieve the desired dewatering results. Once activated, the polymer can be added immediately to the sludge flow flocking line or stored in a batch tank for future use.

The VEPAS can be used in mobile applications such as Geotube® emergency sludge dewatering, or for full-scale Geotube® dewatering applications at wastewater lagoons or water treatment plants. It can be adapted easily into the activated sludge process simply by introducing a polymer feed line into the sludge feed line. The system will run automatically and adjust the amount of polymer added to the sludge based on the flow.


Read More about different types and sizes of the VEPAS.

Read our case study to see how Bishop Water’s solids management solution has been used as part of a long-term dewatering solution at the North Rustico Wastewater Treatment Plant.

Contact Us about your project.

mobile trailer

Mobile Dewatering Trailer


Bench Testing for Optimal Polymer Selection

DATE POSTED: February 22, 2018

Polymer Selection

Selecting the right polymer and dose is integral for maximizing the dewatering process for Bishop Water’s solids management solution. Polymer selection can seem like a daunting task since hundreds of polymers are available and each is formulated to work best with the specific properties of the solids that are being dewatered. To ensure that maximum dewatering occurs in a full-scale system, an experienced polymer specialist from Bishop Water’s team can use bench testing to determine the chemical specifications needed to flocculate and dewater solids at a particular site.
polymer selection
On this episode of the Bishop Water Podcast, Christine Gan, a Wastewater Engineer in Training (E.I.T.) at Bishop Water, describes what type of equipment is used in Bishop Water’s lab to undertake the bench testing and showcases the different types of tests that can be undertaken to optimize the polymer and dosage rates for a site. In doing so, Christine describes how bench testing can provide clients with an accurate picture of how a full-scale solids management solution will operate at their site.


Learn More about our various testing methods.

Listen to the podcast on Soundcloud.

Contact us to arrange a quick, easy, no obligation test of your material.