9 minute read
New automated bioaugmentation system reduces lagoon sludge
By Suzan Chin-Taylor
Seeking solutions to effectively remove its lagoon sludge and reduce the associated costs, the City of Weyburn, Saskatchewan opted to implement a new automated bioaugmentation service technology from EnBiorganic Technologies on a performance trial basis.
Their EBS-Di technology was attractive to Weyburn due to its plug and play readiness, zero capital expenditure and efficiency. In under 60 days, results were demonstrated in the de-sludging of the city’s wastewater lagoons, as well as elim-
The plant’s primary lagoon is 350 acres in size and was experiencing heavy sludge buildup.
ination of odour. An additional benefit to the service was the removal of fats, oils and grease (FOG) within the city’s lift stations, which had long been an issue.
Impressed with the results in such a short period, Weyburn’s utility staff decided to enter an ongoing TaaS (treatment as a service) contract with Vital Utilities and EnBiorganic to continue the work begun in the performance trial.
WEYBURN’S LAGOON SYSTEM
Established in 1901, Weyburn is home to a population of around 10,000. Its utility delivers water, sewer, and wastewater treatment to a customer base of
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approximately 3,500. The city treats its wastewater exclusively through a lagoon system. It includes a 50-acre diversion lagoon and a 350-acre primary lagoon, consisting of two anaerobic sludge cells and a series of nine holding or polishing cells. Wastewater is held for approximately one year in the polishing cells, before the treated effluent is released to the Souris River.
The plant was originally constructed in the 1960s, and expanded in 2011 with additional holding cells, enlarging its primary lagoon to the current area of 350 acres. The city’s public sewer collection system is comprised primarily of 150, 200 and 300-mm vitrified clay pipe (VCP) and PVC mainlines with a single 600-mm diameter trunk line at the connection point of its six lift stations, which feed the treatment plant.
CHALLENGES
Over its years of service, the lagoons have experienced heavy sludge buildup and have never been completely dredged. Some cleaning was performed in 2006, but this only comprised of cleaning around the inlet pipes and pumping the existing sludge to the edges of the lagoon and into its corners. However, nothing was removed.
The new sludge cells did receive a cleaning once after being put into service but nothing further in the way of sludge removal has been performed. Dredging of these cells was quite costly and there were issues with disposal. The material contained hydrocarbons and other contaminants that were at a level above acceptable limits for standard landfill disposal.
In addition to sludge remediation and disposal, Weyburn also experienced a high degree of FOG buildup in its lift stations, that required confined space entry by operators. Normal pressure washer spray techniques could not remove the buildup, as the FOG was so heavy. Yet, regular cleaning was required to keep lift station pumps and floats in good working order.
Odour at the primary lagoon could also be an issue from time to time. Although able to meet compliance permits, Weyburn had been very close to allowable levels and wanted to stay ahead of potential issues.
SOLUTION
The city’s engineering department was researching alternative solutions to costly mechanical dredging and came across EnBiorganic Technologies (EBT). LA Electrical Services, operating as Vital Utilities, an EBT licensee, recommended that Weyburn consider a trial performance of EBT’s EBS-Di autonomous bioaugmentation technology. They felt strongly that this technology could help resolve Weyburn’s sludge issues, associated costs for dredging, disposal, and odour.
“It was a very attractive option to consider,” says Renée Cugnet, municipal engineer for the City of Weyburn. “The solution is not mechanical and would
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not require a large capital expenditure for equipment purchase, or a project to add it onto our treatment facility. Being non-pathogenic, and natural with no byproducts was also a key benefit.”
Because Weyburn had the land space available for using facultative lagoons, constructing a mechanical treatment facility, or process, could not be justified, or considered the best route.
EBS-Di combines the power of customized proprietary soil microbiology with autonomous delivery technology for all-natural, sustainable biological treatment of wastewater.
The EBS-Di units measure approximately 122 cm L x 61 cm W x 91 cm H. Through a patent-pending process, they generate and activate the microbes just before they enter the wastewater system. This means the microbes are immediately ready to go to work.
These microbes can perform with, or without, oxygen and because they are grown in the target water, they are already customized for the application. This translates to reduced retention time requirements. In turn, this lowers the cost per volume treated.
The technology generates, activates, adapts, and dispenses EBT-microbes in one complete package. Using target water as the growth media, the generator conditions it and grows microbe cultures at a rapid pace and on a massive scale.
In Weyburn’s case, the EBS-Di was programmed to produce and release 720 litres per day of active, adapted microbes, capable of growing rapidly with or without air. Because the microbes continue to grow rapidly after release, they double in population every 30 to 150 minutes.
Depending primarily upon temperature, the working population continues to grow rapidly after release, as long as food and nutrients are available. If food or nutrients become depleted, the replication rate slows. If new materials do not appear soon, the microbes will enter into a cannabalistic state. If conditions do not ultimately improve, they will go into a spore state and remain inert, until favorable growth conditions return. In this manner, they are self-regulating.
The generator is positioned where it can inject these microbes into the natural or manmade body of water, at a level that simply overwhelms the inappropriate or problem nutrients or contaminants. All that is required to set it up are a physical footprint to accommodate the equipment, and a reliable electric power source.
The performance trial in Weyburn began in August 2021 and after an economic impact report and assessment, it was determined by EBT that two EBS-Di units would be utilized for the trial. One unit would be placed at primary lift station #1 and the other at lift station #3 in the western part of the city.
Weyburn received some beneficial results immediately after the units went online. Within a few weeks, its collection system operators noticed that, in the lift stations where the units were set up, FOG was falling or sliding off the sides of the walls and not sticking or clumping to the pumps and floats as it always had.
Because of this, operators have not had to enter the lift station for manual cleaning, whereas previously, they were required to perform this task every few weeks. Odours had disappeared in both stations as well.
Prior to the trial beginning, some of the lagoons had sludge piles that were above the waterline. Approximately one month into the trial, these levels noticeably decreased, and the piles were dissipating. It was also noticed that the consistency of the sludge had changed. It was appearing fluffy or suspended, instead of a fixed solid mass as it had been.
Weyburn had tried other methods to deal with its sludge in the past, that included manual addition of powdered enzymes to the lift stations. Natural grease reducing agents were also utilized, primarily for breaking down grease. “Everything seemed to do a little bit, but it just wasn't really effective or continuous,” says utility manager Kim Wilkes.
SUCCESSFUL TRIAL RESULTS
Continuous improvement in the collection system and sludge reduction was proof enough that this was a solution that Weyburn wanted to keep as part of their treatment process. Therefore, they entered a contractual service agreement with multiple extensions.
The EBS-Di is provided on a TaaS contract model and did not require any capital or additional operating expenditures for the city. All service and maintenance will be provided on contract with Vital Utilities, with remote monitoring and control performed by EBT from its laboratory, now that the performance trial is successfully completed.
Although the trial incorporated the deployment of two units, it was determined by EBT’s technical staff and Vital Utilities that a single unit at lift station #3 would be sufficient to achieve the desired results. Historically, EBT has found that units placed further out in the collection system are more effective and can also deliver added benefits to the overall health of the collection system.
“One of the things that I am excited about is not having to have our operators enter potentially hazardous or confined spaces in the wet wells to do the cleaning and maintenance of the FOG that had always built up, and of course the associated labour costs,” says Cugnet. “But the most exciting part is not having to do mechanical dredging of the primary lagoon, or dealing with the separated sludge which we would have to store, transport, and safely dispose of. All of which is very costly and presents environmental and human risks.”
The EBS-Di units generate and activate the microbes just before they enter the wastewater system.
