Robust cold-weather performance and lower cost make BioCord™ ideal choice for lagoon upgrade in Northern Alberta

DATE POSTED: November 30, 2022


BioCord lagoon upgrade for cold-weather biological treatment

Bishop BioCord™ Reactors have been chosen for a unique demonstration project to improve cold-weather biological treatment and effluent quality of the wastewater lagoons serving the Gift Lake Metis Settlement in Northern Alberta. The full-scale project will validate the ability of BioCord’s simple, low-energy treatment process to enhance the removal of ammonia and biochemical oxygen demand (BOD) in the lagoons during winter conditions and produce effluent that meets regulatory requirements for spring discharge to a nearby creek.

“As part of our assessment of the sewage treatment facility, we identified that the lagoons were not adequately treating the effluent as it progressed from one cell to another,” said Glen Pitt, P.L. (Eng), Principal of TeckEra Consulting. “Several upgrading options were evaluated. Bishop Water was engaged to provide technical guidance to improve the system performance without having to re-construct new lagoons or consider a mechanical treatment plant. The BioCord system was ultimately selected as the most cost effective and practical solution. Their personnel were fantastic to deal with and guided us through the initial testing and analysis phase to preparation of the funding application.”

The easy-to-operate, fixed-film reactors will be installed directly into a facultative lagoon cell while the plant remains in operation. BioCord’s in-situ design eliminates the need to expand the plant footprint or to add costly process infrastructure that post-lagoon or sidestream systems require, such as tanks, pipes, and blowers. Modular components will enable the BioCord system to be expanded as the community grows, which will help keep capital and operating costs aligned with near-term treatment needs and fiscal capacity.

BioCord provides a massive surface area on which biofilm thrives.
The BioCord media provides a massive surface area on which preferred, naturally occurring bacteria can attach and grow to produce a robust biofilm and improve year-round lagoon performance.

“BioCord Reactors are like a condominium for bacteria that supports a robust biofilm and increases the population of nitrifying bacteria far beyond what can be achieved in an ordinary suspended growth lagoon,” said Kevin Bossy, CEO of Bishop Water Technologies. “We are grateful for the opportunity to work with the Gift Lake Metis Settlement and TeckEra Consulting on this project and for funding support from the Federation of Canadian Municipalities to demonstrate BioCord’s cold weather performance and lagoon upgrade capabilities.” The Federation of Canadian Municipality Green Municipal Fund is providing a grant of up to $500,000 to cover up to 80% of eligible project costs.

BioCord Reactors will be installed directly into the lagoon cell, near the outlet, and will occupy less than two percent of the lagoon area.

The BioCord Reactors system will occupy a compact footprint of only 80 m2; just a fraction of the total lagoon area of nearly 6,000 m2. Despite the small size, the BioCord system is designed to handle the average flow of 190 m3/day and reduce BOD to less than 5 mg/L, ammonia to less than 1 mg/L and unionized ammonia to less than 0.1 mg/L.

A BioCord Reactors system can also achieve treatment targets using significantly less energy than alternatives, such as MBBR. This is possible because BioCord media is attached to a frame and does not require energy-intensive blowers to provide suspension and circulation of free-floating carrier media. Instead, each Reactor is equipped with an integrated fine-bubble aeration system powered by low-energy compressors. These components provide high oxygen transfer and can achieve the same or greater dissolved oxygen as other systems, while delivering approximately half the air.

“In coordination through our engineering consultant, Bishop Water has assisted our community on two major projects,” said Roger Higgins, Project Manager for Gift Lake Metis Settlement. “The first project was the installation of an OctoAir system and aeration lines. This significantly improved the quality of our drinking water by reducing the manganese levels in the raw water. Our second project is the design and construction of the BioCord system for our sanitary sewage treatment lagoon, which will be installed in early 2023. We are very pleased with the attention to detail and expertise from Bishop Water’s personnel.”

Once installation is completed, the BioCord system will have ample time to establish a robust biofilm and achieve steady-state nitrification for ammonia and BOD removal throughout the following winter.

Watch our video to learn about BioCord’s performance advantages and operation.

Contact us to discuss a BioCord upgrade for your wastewater lagoon.

Learn more about the Federation of Canadian Municipalities Green Municipal Fund for wastewater pilot systems.

AWWA Fuller Award presented to Don Burgess, our rep in Western Canada.

DATE POSTED: October 31, 2022


Don Burgess - AWWA Fuller Award

We are extremely delighted and proud to congratulate our colleague, Don Burgess of DWG Process Supply, on receiving the 2022 George Warren Fuller Award from the American Water Works Association Western Canada Section (AWWA WCS).

The award is presented annually to a member of each AWWA section in recognition of their distinguished service to the water industry, outstanding leadership and significant contribution toward the advancement of the water works practice within the AWWA or the section.  

We heartily agree that Don deserves an award like that. Don has worked with water and wastewater treatment systems his entire career, being involved in various phases of design, construction, operations, and most recently, equipment sales.

Our team has been working with Don since 2017, when he became the manufacturer’s representative for Bishop Water in Western Canada. Since then, Don has played a pivotal role in expanding the awareness of our simple, low-energy treatment solutions in Western Canada, developing applications for our systems and assisting with their implementation.

Don has been an active AWWA member and volunteer for almost 30 years.  He has served on the AWWA WCS Board of Directors as Alberta Trustee 1997-1999, and 2001 to 2005. He has been on numerous Western Canada Water (WCW) Conference Planning Committees and the WCW Alberta Provincial Council for many years, organizing, assisting, and presenting at many workshops.

Don also received the WCW H.C. Lindsten Award in 2001.

Congratulations on this well deserved recognition for your inspirational commitment!

Learn more about DWG Process Supply.

DWG logo

What to do when your lagoon’s effluent TSS is higher than the influent TSS

DATE POSTED: August 31, 2022


Lagoon Aerial

What’s happening in a wastewater lagoon when the TSS of the effluent is higher than the TSS of the influent? And more importantly, how does an operator fix it?

Excess sludge accumulation is often the cause of high effluent TSS and can be accurately diagnosed with a little time, observation and sampling.

The most obvious signs are visible sludge that is floating in the lagoon, or large deposits of sludge that rise close to the surface or above it. When operators sample the lagoon effluent they may notice a change in colour, reduced clarity and an abnormally high or non-compliant TSS level.

As sludge accumulates, storage capacity and retention time diminish, which can adversely impact nutrient removal. This can cause algae blooms and significant increases in TSS and BOD, potentially to
levels that are higher than that of the influent.

Sludge map

Short circuiting is another symptom of excess sludge that can also contribute to high effluent TSS. When this occurs, channels form in the sludge that cause wastewater to travel relatively quickly through the lagoon from the inlet to the outlet, rather than dispersing and remaining for the optimal residence time. The shallow depth of the lagoon may also cause poor settling and carry over of sludge into the effluent.

Benthal feedback might also be the culprit of high effluent TSS, however this condition occurs primarily during the spring in non-aerated lagoons. As the water warms, it creates turbulence that stirs up the sludge blanket and releases accumulated hydrogen sulfide and nutrients. The condition is short-lived, but until the sludge settles, the lagoon could emit malodours and experience high TSS and nutrient levels in the effluent.

Sludge removal often solves the problem

A sludge survey is an important first step to measure the thickness of the sludge blanket and how it’s distributed throughout the lagoon cell. Following that, Bishop Water can discuss important sludge management considerations and actions including:

  • Current lagoon capacity vs. design capacity
  • Depth and distribution of sludge
  • Location and volume of recommended sludge removal
  • Available budget and operational objectives
  • Partial vs. total lagoon sludge cleanout

Depending on the results, urgency and budget availability, a total cleanout might be the right approach, or a partial cleanout to remove sludge only from areas of concern and defer the full cost to a future fiscal year.

Once a plan is ready, our team can begin mobilizing sludge removal equipment and the Bishop Solids Management Solution. This process provides a simple and cost-effective way to collect, dewater and contain sludge and achieves a high level of dry solids using only polymer conditioning, Geotube™ containers and gravity.

Compared to alternatives like centrifuges and belt presses, the Bishop Solids Management Solution is less complex, more energy efficient and can collect and dewater sludge at a significantly higher rate, which means projects can be completed faster and more affordably.

Read our case study to learn how a lagoon sludge cleanout enabled the O’Leary WWTF in PEI eliminate exceedances of TSS, BOD and coliform bacteria as well as blue-green algae blooms.

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

Contact us to discuss operational issues such as high effluent TSS and how a lagoon sludge cleanout can help.

How to remove more phosphorus with less coagulant

DATE POSTED: July 27, 2022


ClariPhos forms a tight bond with phosphorus

How can a wastewater treatment plant improve phosphorus removal while reducing the amount of coagulant it’s using? The answer: switch to a coagulant that forms a strong, preferential bond with phosphorus. 

Here’s why that works. 

ClariPhos bonding comparison

Conventional aluminum- or iron-based coagulants don’t form a strong bond with phosphorus. Instead, they first form metal oxide intermediates, which is followed by phosphate adsorption to the metal oxide. This is a relatively weak bond that is reversible and non-specific to phosphorus, which means that more coagulant is needed to achieve low effluent phosphorus concentrations. 

Bishop Water’s ClariPhos™ is made with the rare earth elements cerium and lanthanum. These elements have a very high affinity for phosphorus and quickly form rhabdophane, a dense and insoluble precipitate. Rhabdophane is a stable mineral that naturally occurs and will not re-solubilize and release phosphorus back into the treated effluent.

High affinity and strong bonds reduce coagulant dosing 

Since ClariPhos has a strong tendency to combine with phosphorus it is far more efficient than conventional coagulants, so less is needed to remove an equivalent amount of phosphorus. Plants that have switched to ClariPhos report dose rates that are up to eight times lower than those of conventional coagulants. 

The graph below, compares the dose rates (in moles) of ClariPhos against several aluminum- and iron-based coagulants to achieve a range of phosphorus targets. As the phosphorus targets drop, the dose rates for the aluminum- and iron-based coagulants increase significantly. To achieve 0.1 mg/L, these coagulants the dose rates range from 3:1 to almost 8:1. 

Dosing rates of coagulants for phosphorus removal

ClariPhos, by comparison, can achieve 0.1 mg/L of phosphorus in treated effluent at a molar dose rate that is about 1:1. That not only reduces chemical consumption, it can dramatically reduce sludge production too. Wastewater plant operators have seen sludge volumes decrease by as much as 50% with improvements in sludge dewaterability of up to 40%. 

Learn more about ClariPhos Rare Earth Coagulant. 

Contact us to talk about switching to ClariPhos for your wastewater treatment plant. 

Bishop Water joins Chedoke Creek cleanup

DATE POSTED:


Chedoke Creek cleanup

Bishop Water will be joining a team of environmental remediation specialists, that includes Milestone Environmental Contracting Inc. and ECO Technologies Ltd., to complete the targeted dredging of  Chedoke Creek in Hamilton, Ontario. The project, scheduled to start late this summer, aims to remove over 10,000 cubic metres of nutrient-rich contaminated sediments from a 19,000m2 section of the creek. 

As part of the project, our technicians will set up and operate the Bishop Solids Management Solution (BSMS) to provide a simple, low-energy process to collect and dewater the material that is dredged by ECO Technologies. This system uses only a fraction of the energy that more complex alternatives such as centrifuges require. Rather than spinning or squeezing the material, the BSMS is a passive process that uses only Geotube® geotextile containers, polymers and gravity. 

The Bishop Solids Management Solution achieves a high level of dry solids using only Geotube geotextile containers, polymers and gravity.

Bench tests performed in our laboratory verified that the BSMS process will effectively dewater the sediments and achieve a high level of dry solids . This low-energy reduction in volume means that fewer trucks will be needed to transport the sediments off site, thereby decreasing greenhouse gas emissions and local traffic.  

Our technicians will work with the general contractor, Milestone Environmental, to construct two lined dewatering cells within a dredge material management area upland of the creek. Each of these cells will contain several massive Geotube containers, measuring 36.5 metres in circumference and either 34.7 or 30.5 metres in length. 

The hydraulic dredge will pump sediments directly to the Geotube and a manifold system will enable operators to quickly and easily route the flow to maintain the high pumping speed while allowing filtrate to drain from the containers. The lined cell will also contain the filtrate from the Geotube units and collect it for a dedicated pump to transfer the water to the city sewer system for treatment. 

We look forward to working with our colleagues from Milestone Environmental and ECO Technologies on this important environmental remediation project for the City of Hamilton. 

Learn more about the Bishop Solids Management Solution for dewatering and containment of contaminated sediment and other slurried materials. 

Contact us to discuss your slurry dewatering needs. 

One of our Geotube® shoreline systems makes a cameo in an educational video

DATE POSTED: June 29, 2022


One of our Geotube® Shoreline Systems is part of a new video from Healthy Lake Huron that provides essential information for waterfront property owners to assess, plan and mitigate erosion, flooding and unstable soil. 

In the video, a flyover of our Geotube installation at Port Franks, Ontario shows a wintery view of ice, snow and debris up against the 150-foot long, two-layer revetement. The system was installed in July 2021 as part of a project to protect the house from erosion and restore the sand and vegetation that had been washed away by high waves during storm events. 

The photo below shows the property before and after the sand was replaced and the Geotubes were installed. The erosion was quite severe and had advanced nearly to the cottage, putting it at risk of collapsing. 

Geotube shoreline before and after

Geotube Shoreline Protection is ideal to tackle increasing shoreline erosion and offer several advantages over conventional rip rap, armor stone or gabion baskets. 

  1. Virtually immovable mass – Once filled, a Geotube forms a monolithic structure that weighs many tonnes and is extremely difficult for waves, debris and ice to shift the Geotube container. The system rests on a specially designed scour apron which prevents waves from undercutting and compromising the structure. This is especially important when Geotubes are used to stabilize the toe of a bluff and protect it from wave attack.
  2. Deflective elliptical shape – As debris or ice advances towards the shoreline, the elliptical shape of the Geotube containers can deflect the material and force it up and over the structure. Conventional barriers made of materials such as armour stone or timber face the ice head-on and are often dislodged or heaved up.
  3. Durable, impact-resistant technology – Geotube containers are specially designed for shoreline protection and are manufactured using high-strength polypropylene multifilament yarns that meet several ASTM standards for fabric strength, seam strength, UV resistance and puncture resistance.
  4. Versatility and customizability – Geotube shoreline systems are available in several configurations and sizes. Each one is designed to provide maximum performance, lifespan and ease of installation. Many can also be custom manufactured to meet site specifications.
  5. Fast and easy to install – Geotube containers are filled in-place with a slurry mix of sand and water or locally dredged material. This simple process enables Geotube® containers to be installed much more quickly than conventional approaches such as armour stone or concrete.

Watch the video.

Learn more about Geotube Shoreline Protection Systems. 

Contact us to discuss Geotube shoreline protection for your property. 

Crafting a simple, affordable system to treat brewery wastewater and avoid sewer surcharges

DATE POSTED:


Solids and wastewater management for craft breweries

Sewer surcharges can significantly impact the bottom line for breweries and other food and beverage processors. Adding an onsite wastewater treatment plant is one way to reduce sewer surcharges, but many options are costly, complex, and require a significant amount of space, which can make it tough to decide whether to install a system or continue paying higher fees to the utility. 

Bishop Water recently completed pilot testing of an easy-to-operate, compact system at an Ontario craft brewery to demonstrate its ability to reduce the contaminants that are discharged to the municipal sewer and potentially eliminate sewer surcharges. 

A simple system for process solids and nutrients

The system combines two of our proven technologies, the Bishop Solids Management Solution and Bishop BioCord™ Reactors, to create a treatment train that can efficiently and affordably remove target contaminants like TSS, BOD, COD and adjust pH to the required discharge limits. 

It’s a challenging task. The raw wastewater from the brewery that the pilot system was treating had a pH of 4.6, and average concentrations of COD and ammonia of 42,822 mg/L and 116 mg/L respectively. 

Despite the high strength of this wastewater, we’ve designed the pilot system to operate with little operator oversight, low-energy consumption, few components and reliable performance. Here’s how it works. 

  • Raw wastewater is pumped to a mixing tank where a coagulant and flocculant are added to remove TSS and fine particles and pH is adjusted to the required range. 
  • Flocculated material is pumped to a Geotube geotextile dewatering bag, which retains the solids and releases clear, low-TSS filtrate. 
  • BioCord Reactors, an aerated, fixed-film biological treatment system, provides robust, low-energy removal of soluble BOD, COD and ammonia. 

Our pilot system ran for about a year and consistently achieved a high level of contaminant removal, even though there were significant fluctuations in loading rates, which can be seen in the graph below.  

The results showed the following: 

  • Average TSS removal efficiency of 99%
  • Average COD removal efficiency of 72.59%
  • pH consistently adjusted to 7.6
BioCord Reactors COD Removal
Total COD concentrations in the influent and the effluent to the BioCord Reactor

We also noted that the BioCord system achieved simultaneous COD and ammonia removal, achieving average ammonia removal efficiency of about 36%. BioCord is capable of achieving greater than 90% ammonia, and although ammonia removal was not a target contaminant in this study, the rate could be improved by reducing the C:N ratio of the influent. 

Although the pilot system was small, with a BioCord Reactor volume of only 120L, the system is easily scalable and customizable to handle larger flows and greater loading of TSS, COD and BOD from breweries or food processors. It also operates with fewer components, uses less electricity and requires less oversight and maintenance than alternative treatment technologies such as MBBR or MBR. 

Although the pilot system was small, with a BioCord Reactor volume of  only 120L, the system is easily scalable and customizable to handle larger flows and greater loading of TSS, COD and BOD from breweries or food processors. It also operates with fewer components, uses less electricity and requires less oversight and maintenance than alternative treatment technologies such as MBBR or MBR. 

Read the paper Wudneh Shewa presented at the WEAO 2022 Annual Conference, Using Compact, Low-energy Onsite Systems to Treat Brewery Wastewater with High Levels of BOD and TSS

Learn more about our Bishop Solids Management Solution and BioCord Reactors for simple, low-energy treatment of high strength wastewater from breweries and food and beverage processing. 

Contact us to discuss a system for your facility. 

ClariPhos™ receives ECA for phosphorus removal, enabling pilot testing throughout Ontario

DATE POSTED: June 1, 2022


ClariPhos Clarifier

Bishop Water now has an Environmental Compliance Approval (ECA) for our ClariPhos™ Rare Earth Coagulant, which means we can simplify the process to temporarily replace conventional coagulants and demonstrate the impressive phosphorus removal abilities of this product at wastewater plants throughout Ontario.

Our ECA enables wastewater plants that don’t have Limited Operational Flexibility ((LOF) to conduct a ClariPhos pilot without amending their current ECA. Once the performance and benefits of ClariPhos have been validated, plant administrators can apply to change their ECAs.

ClariPhos is a game-changing technology that dramatically outperforms aluminum- or iron-based coagulants for phosphorus removal. With ClariPhos, wastewater treatment plants can achieve ultra-low phosphorus limits—as low as 0.07 mg/L—without the need to install or upgrade costly tertiary filtration systems.

ClariPhos maintains a 1:1 molar dose ratio, even when achieving ultra-low phosphorus limits. By comparison, conventional coagulants are typically dosed at a 5:2 molar ratio and can climb as high as 8:1. As a result, ClariPhos can reduce sludge production by as much as 50% and the associated costs of sludge management.

ClariPhos Sludge Comparison
A comparison of sludge produced to remove an equivalent amount of phosphorus.

Switching to ClariPhos is easy.
In most cases, operators can replace conventional aluminum or iron coagulants with ClariPhos. The product requires no special chemical feed equipment and will often work with existing feed pumps.

Bishop Water provides comprehensive services for a pilot or full-scale implementation of ClariPhos. Our team will assess your plant’s current phosphorus removal equipment and operation to determine the optimal dosing location and dose rate. Samples will also be obtained at various points in the treatment process to optimize ClariPhos performance through steady conditions as well as variable flows and loads.

Once ClariPhos is fully implemented, Bishop Water can provide ongoing support through routine technical service visits and ongoing sampling, analysis and optimization.

A ClariPhos pilot may be eligible for funding from the Federation of Canadian Municipalities Green Fund, which supports innovative wastewater treatment initiatives.

FCM

Learn more about ClariPhos Rare Earth Coagulant.

Contact us to discuss a ClariPhos pilot or switch for your treatment plant.

ClariPhos™ coagulant improves UV disinfection for Ontario WWTP

DATE POSTED: April 29, 2022


How much can a phosphorus coagulant influence the performance of a wastewater plant’s UV disinfection system?

A lot more than you might think.

After switching to ClariPhos™ Rare Earth Coagulant to evaluate its ability to improve phosphorus removal, operators at an Ontario WWTP noticed that UV disinfection also experienced a big boost. It turns out that better settling in the clarifier led to higher UV transmittance in the effluent, and a significant improvement in UV disinfection.

ClariPhos UVT and E.coli

Better clarifier performance = higher UVT
UV transmittance, or UVT, is a measurement of the UV energy that passes through a water column relative to the energy emitted by a UV lamp. Low UVT means that suspended or dissolved contaminants are blocking or absorbing UV light and preventing the UV energy from reaching target pathogens.

High UVT means the opposite. In this case, UV light can easily pass through the water column and effectively inactivate pathogens.

Prior to switching to ClariPhos, the plant was using ferric chloride to precipitate phosphorus. With this chemical, the plant typically achieved UVT in clarified effluent of about 55 – 60%.

With ClariPhos, the plant was able to consistently achieve UVT above 60%, enabling better performance from the UV disinfection system.

ClariPhos outperforms Al- and Fe-based coagulants
ClariPhos improves clarifier performance because it is made with the rare earth elements cerium and lanthanum, which have a very high affinity for phosphorus. These elements form a tight ionic bond with phosphorus to create rhabdophane (Ce/LaPO4), a dense and insoluble precipitate.

ClariPhos Rare Earth Coagulant

ClariPhos precipitate is also more stable and heavier than that produced by Al- or Fe-based coagulants so it settles up to two times faster. The results are improved clarifier performance and reduced risk of carryover of suspended solids.

Switching to ClariPhos is easy. In most cases, plant operators can simply replace conventional alum or ferric coagulants with ClariPhos to easily and cost-effectively improve the chemical precipitation and settling of phosphorus. ClariPhos requires no special chemical feed equipment and will often work with existing feed pumps.

Learn more about ClariPhos and how it helps improve phosphorus removal, reduce sludge production and boost the performance of UV disinfection.

Contact us to discuss switching your phosphorus coagulant to ClariPhos.

The advantages of low-energy, high-performance Geotube dewatering for biosolids management

DATE POSTED:


Geotube dewatering

Spinning, squeezing, solar drying, there are many ways to dewater sludge from treatment plants and produce stabilized biosolids that are ready for land application or disposal. Selecting the best approach often considers several factors, including the speed at which dewatering must be completed, the space that’s available at the treatment plant to accommodate the process, and capital and operating costs.

Simple solutions such as solar drying may seem less costly initially, but the process is laborious and time-consuming and may drive up staff costs. Mechanical processes may work more quickly, but often incorporate complex, energy-intensive mechanical equipment that is costly to buy, maintain and operate.

Geotube® Geotextile dewatering of wastewater sludge provides simple, low-energy operation, efficient dewatering with little operator attention, and a customizable footprint to fit the plant configuration.

Single-step process for solids collection, consolidation and dewatering

The Bishop Solids Management Solution is used by municipal and industrial treatment plants throughout Canada to capture, dewater and consolidate solids in a single step. The system incorporates Geotube geotextile containers and a unique Venturi Emulsion Polymer Activation System (VEPAS™) to do the bulk of the work. Dewatering is achieved largely by gravity, which helps reduce capital cost, simplifies operation and makes the system very energy efficient. Electricity is required only for the sludge feed pump and the VEPAS.

VEPAS
The compact VEPAS automatically activates and injects polymer in a single step to enhance dewatering and retain contaminants.

Geotube containers are made from a high-strength, tightly woven polypropylene fabric that provides both containment and filtration. Solids can be pumped directly from sludge storage tanks, lagoons or digesters to the Geotube. Along the way, the VEPAS activates and adds polymer on the fly, directly into the sludge feed line. This innovative system can operate automatically and eliminates many of the components in mechanical polymer systems, such as mixers and tanks, which take so much time to maintain and clean.

The specially selected polymer performs several functions in the process. It accelerates the dewatering process, enabling filtrate to flow almost immediately through the pores of the Geotube container and preventing clogging. The polymer also helps retain BOD, TSS and many other organic and inorganic contaminants in the dewatered solids.

Depending on the application and discharge regulations, the filtrate could also meet permit limits for release into a receiving body or non-potable reuse. At a municipal treatment plant, the filtrate would typically be sent back to the headworks for treatment prior to discharge.

Filling a Geotube container usually occurs in batches, so it may take several pumping sessions over a period of weeks or months before the container is full. After each session, the container is allowed to dewater, which reduces the volume and creates space for additional sludge to be added. This process can occur year round, even in cold climates. Where temperatures fall below freezing, a greenhouse can be cost-effectively built to maintain temperatures above freezing and ensure filling and dewatering is possible.

Once the container is full, it will undergo a period of consolidation where dewatering continues and a composting effect reduces pathogens. Solids content can go as high as 40% and the process emits no significant odour, simplifying the handling and reuse of the solids as a soil amendment.

Replacing solar drying beds to reduce labour costs

The Meteghan Sewage Treatment Plant (STP) in the Municipality of Clare, Nova Scotia, used to spread sludge onto drying beds. Then, after drying the sludge for about a month, operators would rake it by hand into wheelbarrows and load it into trucks for disposal. It was a lengthy, time-consuming process that dramatically reduced the amount of time that operators could spend on much-needed infrastructure projects, such as plant process optimization and reducing inflow and infiltration in the collection system.

The Bishop Solids Management Solution replaced solar drying beds at the Meteghan STP to dramatically reduce the amount of time operators spend on sludge management.

In November 2016, the Meteghan STP began using a Bishop Solids Management Solution, enabling the plant to collect and dewater the same volume of sludge in about five hours, rather than several weeks. Since commissioning, the plant has dewatered over 1 million litres of sludge and has saved hundreds of hours in labour.

Sludge from the plant is pumped directly from the sludge storage tank to a Geotube geotextile container, which provides storage, consolidation and passive dewatering of the sludge. As the sludge is pumped, a specially selected polymer is added to accelerate and enhance the dewatering process.

The dewatering cell, which occupies about 232 m2 was constructed in the same location as the drying beds and is capable of accommodating two Geotube containers. Each container is about 13.7 m in circumference and 17.4 m long.

A cost-effective method to accept septage at a municipal plant

The Eganville Wastewater Treatment Plant (WWTP) in Ontario, has operated a sludge and septage dewatering facility since 2008, using the Bishop Solids Management Solution. This innovative facility has a dual purpose, providing a simple, low-energy process for dewatering and stabilizing aerobically digested sludge from the municipal treatment plant, as well as septage brought in by local haulers.

The process not only simplifies sludge management from the treatment plant, it also provides a local facility where haulers can empty septage. Many treatment facilities are unable to accept septage and haulers often travel great distances to empty their trucks. This is a time-consuming process that results in added costs for property owners and increased greenhouse gas emissions from vehicles.

The Eganville WWTP has used the Bishop Solids Management Solution since 2008 to dewater sludge and accept septage from local haulers.

Sludge from the treatment plant and septage from haulers are both sent to a 37.8 m3 underground holding tank, which is recirculated once full to ensure the solids are well blended. Pumps then move the sludge to a Geotube container. As the sludge is pumped, polymer is added directly into the feed line to enhance the dewatering process and help retain contaminants in the container.

The laydown area can accommodate up to six 15.25 m long Geotube containers, two of which are set up inside a greenhouse. The greenhouse maintains an indoor temperature above freezing and enables the facility to receive and dewater sludge and septage year round.

After a period of dewatering and stabilisation, the biosolids are typically sent to the municipal landfill where they are not buried, but instead used as a soil amendment to the final cover.

Eganville WWTP continues to accept septage from local haulers on a fee-for-service model, which helps support the operation and potentially opens new revenue opportunities by extending the service to a wider area of haulers.


Learn more about the Bishop Solids Management Solution.

Contact us to discuss a simple, low-energy system to collect, dewater and consolidate sludge at your wastewater treatment plant.