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Projects Overview


Our water works.

We stand by our projects with pride and a commitment to seeing them produce quality effluent for generations.

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Projects Overview


Our water works.

We stand by our projects with pride and a commitment to seeing them produce quality effluent for generations.

At Nexom, we've provided over 200 water and wastewater projects throughout North America and around the world.

From mechanical plants to lagoon-based wastewater treatment, whether in the United States or Canada, Nexom's projects are on the cutting edge of treatment for nutrients and energy efficiency.

The following case studies illuminate some of the more interesting, exciting, and representative work we've had the privilege to work on.

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Sundridge ON: SAGR & infini-D


Sundridge, Ontario

Phosphorus removal using the infini-D Zero-Downtime Cloth Disk Filter

Sundridge ON: SAGR & infini-D


Sundridge, Ontario

Phosphorus removal using the infini-D Zero-Downtime Cloth Disk Filter

 

Project Information

Location: Sundridge, Ontario

Project Type: Municipal Wastewater Treatment - Lagoon-based Phosphorus Removal

Completion Date: March 2014

Treatment Objectives

Design Flow:
454 m3/day (0.12 MGD)

Effluent Quality:

  • 9.6 mg/L TAN in Summer
  • 10.4 mg/L TAN in Winter
  • 25 mg/L cBOD5
  • 70 mg/L TSS
  • 0.27 mg/L TP

Project Background & Challenges

Lagoons—particularly the newer aerated lagoons—are effective at removing cBOD5 and Total Suspended Solids, but they struggle to remove ammonia and nutrients, including nitrogen and phosphorus. Unfortunately for Ontario’s ecosystem, wastewater rich in phosphorus has long been known to cause destructive algae blooms on the Great Lakes.

So when lagoons can’t keep up, small communities have traditionally found themselves facing a big bill to abandon the existing infrastructure and build a new mechanical wastewater treatment plant. That’s what the community of Sundridge, Ontario thought. Nestled on the northern shore of Bernard Lake, just south of North Bay, Sundridge was concerned about its lagoon discharging as effluent containing up to 8 mg/L of phosphorus into the Lake Huron watershed, not to mention ammonia and fecal coliform.

But they don’t worry about that anymore, thanks to some Nexom ingenuity.

The Nexom Answer

Sundridge, Ontario's treatment facility process flow.

Sundridge, Ontario's treatment facility process flow.

Removing phosphorus from lagoons is typically a matter of binding it to another element (e.g. alum) to create a phosphate floc, then settling or straining those flocs out of the water. The challenge, then, is optimizing the timing of each stage to minimize the alum usage.

At Sundridge, the engineers at Nexom came up with an innovative phosphorus removal solution. They installed the two-tank infini-D system, where the first tank rapidly mixes the alum and wastewater, followed by a second tank that mixes more slowly, allowing the new aluminum phosphates to flocculate.

The matter of filtering the floc out is yet another challenge. The centrepiece of the Sundridge system is the infini-D Zero-Downtime Cloth Disk Filter. Individual disc filter cartridges can be easily and cost-effectively exchanged or cleaned without taking the system offline. In Sundridge, where they targeted an effluent phosphorus level of 0.27 mg/L, the engineers chose to place the disk filter after the lagoons and the Nexom SAGR so the majority of the phosphate flocs could settle out well in advance, improving the phosphorus-removal performance and further saving operating costs on the disk filters.

Site Construction

Upgraded System Performance

With 18 months of data under its belt, covering more than 75 discrete samples, the Sundridge plant has seen influent phosphorus as high as 8.3 mg/L, but it has yet to produce one effluent result over 0.1 mg/L, with more than two-thirds of those measurements not registering a detectable level of phosphorus at all (anything below 0.03 mg/L registered as undetectable on the test).

In fact, the whole lagoon upgrade is performing impressively. By baffling the existing lagoon, Sundridge now has an anoxic cell for nitrate removal and phosphate settling, followed by three aerated cells for cBOD5 and TSS removal. The addition of the SAGR allows for full nitrification of the wastewater’s ammonia, working around northern Ontario’s low wastewater alkalinity levels by dosing the influent with soda ash and recycling some of the SAGR effluent back to the lagoons. In addition, the SAGR reduces effluent coliform levels, so a subsequent disinfection stage was deemed unnecessary.

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Glencoe ON: SAGR


Glencoe, Ontario Municipality of Southwest Middlesex WWTP Upgrade

Glencoe ON: SAGR


Glencoe, Ontario Municipality of Southwest Middlesex WWTP Upgrade

 

Project Information

Location: Glencoe, Ontario

Project Type: Municipal Wastewater Treatment

Completion Date: March 2011

Treatment Objectives

Flow capacity increase:
From 946 m3/day to 1742 m3/day
(0.25 MGD to 0.46 MGD)

Effluent Quality:

  • 1.0 mg/L TAN in Summer
  • 3.0 mg/L TAN in Winter
  • 10 mg/L BOD5
  • 10 mg/L TSS
  • 0.3 mg/L TP

Project Background & Challenges

Southwest Middlesex's WWTP consisted two facultative (parallel) wastewater treatment lagoons were in operation since 1974-75. The lagoons were designed for seasonal discharge (early spring and late fall) with a maximum of 946 m3/day average daily flow. As of 2005, the facility was already operating at maximum hydraulic loading. An upgrade was required to meet current and future demand. In order to attain the capacity increase without constructing additional lagoons the process was to be converted from seasonal to continuous discharge. This required the effluent quality meet permit requirements on a year round basis.

The Nexom Answer

Glencoe, Ontario's treatment facility process flow.

Glencoe, Ontario's treatment facility process flow.

Nexom's optAER wastewater treatment with a SAGR for nitrification was implemented as an upgrade to the facility. With a design flow capacity of 1,742 m3/day the upgraded system has nearly twice the maximum hydraulic capacity of the previous design. The capacity increase will meet future demands based on a 30 year design life. The added capacity also creates room for surrounding communities to tie into the system, including the Hamlets of Appin and Melbourne.

Of the two previous facultative treatment lagoons, only one is in operation. The eastern facultative cell was taken offline, leaving it for use as a storage facility when needed (e.g. maintenance or bypass of the western treatment cell). The western cell was divided into three cells using geo-membrane floating baffle curtains to divert flow and effectively maximize the hydraulic retention time by preventing short circuiting. optAER Fine Bubble diffused aeration was implemented in the partitioned cells to achieve improved year-round cBOD5 and TSS removal through bacterial degradation and solids settling.

Lagoon based treatment systems provide some ammonia removal (nitrification) during the summer months, but are generally incapable of meeting low ammonia limits during prolonged periods of low water temperatures. The SAGR tertiary treatment system was developed to address this issue. The Glencoe treatment facility consists of two SAGR beds. The SAGR process is followed by phosphorus removal system by others.

Site Construction

Upgraded System Performance

Glencoe's optAER-based wastewater treatment (with a SAGR) is able to consistently meet ammonia effluent limits of < 1.0 mg/L in summer, and < 3.0 mg/L in winter with water temperatures as low as 0.5°C. As an added benefit, the SAGR process provides BOD5 and TSS polishing to < 10/10 mg/L on consistent basis.

In addition to increased capacity and improved effluent quality, the overall footprint of the facility was approximately decreased in half which allows for future expansion without a footprint increase.

The components and design approach for the Glencoe wastewater water treatment process demonstrates the ability to increase hydraulic capacity and provide nutrient removal in a lagoon based process. The current design also maximizing the use of existing lagoon infrastructure and maintains low operation and maintenance costs.

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Long Plain FN, MB: SAGR


Long Plain First Nation, Manitoba replaces SBR with a lagoon and SAGR

Long Plain FN, MB: SAGR


Long Plain First Nation, Manitoba replaces SBR with a lagoon and SAGR

 

Project Information

Location: Long Plain First Nation, Manitoba

Project Type: Municipal Wastewater Treatment

Completion Date: June 2012

Treatment Objectives

Design Flow:
998 m3/day (0.264 MGD)

Effluent Quality:

  • 1 mg/L TAN (Summer)
  • 5 mg/L TAN (Winter)
  • 10 mg/L cBOD5
  • 10 mg/L TSS

Project Background & Challenges

First Nations communities in Canada, are faced with many challenges of maintaining a proper water and wastewater treatment facility. A number of First Nation treatment facilities are located in remote areas where cold climate conditions create difficult construction challenges due to limited road access areas, equipment, and certified personnel. With aging water and wastewater infrastructure many First Nation facilities are overloaded, and struggle to find the technical and financial resources to keep up with new federal regulations.

Long Plain First Nation (Ojibway) is a community located in the central plains region of Manitoba. Due to facility age and population growth, the existing SBR (sequencing Batch Reactor) was not meeting effluent quality requirements. An upgrade was required.

The Nexom Answer

Long Plain First Nation's treatment facility process flow

Long Plain First Nation's treatment facility process flow

In the spring of 2012, construction began on the facility upgrade. A two - cell, partial mix aerated lagoon based system was constructed on a green-field site for improved year-round TSS and BOD removal. The SAGR® process was installed to provide nitrification (ammonia removal); two vertical flow, continuous backwash sand filters with alum addition were implemented for final polishing and phosphorus removal. The water quality produced by the system allows for continuous discharge to the Assiniboine River

Ease of operation was a primary consideration during development of the SAGR®. There are no sludge or solids management requirements, making the operation and maintenance of the process similar to that of a conventional aerated lagoon. The only moving parts in the system are blowers supplying oxygen to the process. Process control requirements are limited to seasonal (twice a year) manipulation of the influent control valves.

Site Construction

System Performance

After successful construction completion, Nelson Environmental staff provided commissioning and operational training in June 2012. Since commissioning, the results have consistently been meeting the new federal regulations for all parameters.

Conclusion

Long Plain First Nation now has an operator-friendly, technologically advanced wastewater treatment system capable of handling the increasing population. The system will meet federal wastewater regulations, is environmentally responsible, and puts the Long Plain First Nation at the forefront of small community wastewater treatment in Canada.

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Mentone IN: SAGR


Mentone, Indiana wastewater facility upgraded without abandoning existing lagoons

Mentone IN: SAGR


Mentone, Indiana wastewater facility upgraded without abandoning existing lagoons

 

Project Information

Location: Mentone, Indiana

Project Type: Municipal Wastewater Treatment

Completion Date: March 2011

Treatment Objectives

Design Flow:
454 m3/day (0.12 MGD)

Effluent Quality:

  • 9.6 mg/L TAN in Summer
  • 10.4 mg/L TAN in Winter
  • 25 mg/L cBOD5
  • 70 mg/L TSS

Project Background & Challenges

The Town of Mentone, located in Kosciusko County, Indiana, is known as the “Egg Basket of the Midwest” because of the commercial egg production in the region. With just over 1,000 residents, Mentone is a typical small town, and faces challenges common to many other small communities in North America with the dilemma of an aging lagoon-based wastewater treatment facility and new effluent quality limits.

Mentone’s existing wastewater treatment facility consisted of a two-cell facultative lagoon system providing secondary treatment. This facility was designed to meet effluent BOD5/TSS limits of 25/70 mg/L, but was unable to meet the required National Pollutant Discharge Elimination System (NPDES) limits for Total Ammonia Nitrogen (TAN) of 9.6 mg/L in summer and 10.4 mg/L in winter.

Mentone, like a majority of small communities in North America, was left with no choice but to upgrade their WWTP. Until recently, mechanical plants were the only upgrade alternative that can meet low nutrients, BOD5 and TSS limits on a year round basis. Mechanical plants require a large infusion of capital for construction, operation and maintenance. The alternative to these costs prohibitive upgrades is to remain non-complaint. The latter of which is not an option.

The Nexom Answer

Mentone, Indiana's lagoon-based wastewater treatment facility with SAGR post-lagoon nitrification.

In collaboration with the town’s engineering consultant, Nexom designed an upgraded system utilizing the existing facultative lagoons in series followed by a SAGR for post-lagoon nitrification (ammonia converted to nitrates) and BOD/TSS effluent polishing.

Mentone’s SAGR system consists of two gravel beds each capable of handling 100% flow in the summer in the rare case that maintenance would have to be performed within a single bed. No changes were made to the facultative lagoons infrastructure. In Mentone, no aeration was required in the lagoons to meet the recommended lagoon effluent BOD5 feeding the SAGR process. The upgrade was completed without acquiring additional land, or taking either of the existing lagoon cells off-line.

The blowers for the SAGR are sized to meet the oxygen requirements for nitrification and final BOD polishing only. This translates to significant energy savings that would otherwise be required to run blowers for a conventional aerated lagoon system. It is estimated that 50% energy savings are realized with this design compared to other systems achieving similar effluent quality. The trade-off is the higher lagoon footprint required for the necessary residence time. Since the capacity was available at the onset of the system design, utilizing the existing infrastructure was deemed the most cost effective approach. Utilizing the existing lagoons provided cost savings both in the construction and long term operation and maintenance of the system.

Site Construction

Upgraded System Performance

Nexom provided system commissioning and operational training on March 24, 2011. Following a two week startup window, the effluent quality from the Mentone facility is meeting TAN, BOD, and TSS NPDES permit requirements on a year round basis. The system design flow is 0.12 MGD (454 m3/day).

Conclusion

The upgrade of the facility utilizing the SAGR process enabled the Town of Mentone to not only meet but surpass current NPDES requirements. Utilizing the facultative lagoons for secondary treatment by the SAGR process for nitrification and BOD/TSS polishing will lead to an estimated 50% operation and maintenance savings compared to a fully mechanical aerated treatment system.

The upgraded system in Mentone, IN provides an example of a cost effective and efficient solution for WWTP operators in North America who face the same regulatory challenges, and want to keep their existing lagoon system while maintaining low operation complexity.

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Doaktown NB: optAER


Doaktown,
New Brunswick
optAER lagoon system helps protect local fishing industry

Doaktown NB: optAER


Doaktown,
New Brunswick
optAER lagoon system helps protect local fishing industry

 

Project Information

Location:
Doaktown, New Brunswick

Project Type:
Municipal Wastewater Treatment

Completion Date: 2011

Treatment Objectives

Design Flow:
640 m3/day (0.14 MGD)

Effluent Quality Requirements:
10 mg/L cBOD5
10 mg/L TSS
  1 mg/L Total Ammonia (Summer)
  7 mg/L Total Ammonia (Winter)

Project Background & Challenges

The Village of Doaktown is located in Northumberland County, New Brunswick and discharges its wastewater to the Miramichi River. The Miramichi River once supported one of the largest Atlantic salmon populations in North America and today continues to support a large fishery. The river attracts recreational fly fisherman from all over the world. The New Brunswick Department of Natural Resources has implemented rules and regulations for fishing, as well as the wastewater effluent that is discharged into the river, in order to protect the salmon population.

The Nexom Answer

Doaktown's treatment plant process flow

Doaktown's treatment plant process flow

Doaktown chose Nexom's optAER wastewater treatment system to both increase the capacity and improve effluent quality of their lagoon system. The upgrades included:

Site Construction

Upgraded System Performance

With the lagoon upgrades in place, Doaktown has been able to get its cBOD5 and TSS numbers down averages of 7.4 and 12.6 mg/L respectively, even before the water hits the SAGR that has itself been shown to remove 90%+ of both.

Although this case study places the focus on the optAER-enhanced lagoon performance, the treatment objectives set targets for the effluent from the entire system, including the post-lagoon SAGR. To that end, the system has been achieving remarkable results.

During the summer months, when the system targets 1 mg/L, samples have average 0.2 mg/L. But perhaps even more impressivley, in the cold of winter, when targets imposed on the system are 7 mg/L, effluent samples have averaged less than 0.9 mg/L.

Conclusion

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Rocky Mountain House AB: optAER


Rocky Mountain House, AlbertaoptAER increases lagoons' capacity without increasing footprint

Rocky Mountain House AB: optAER


Rocky Mountain House, AlbertaoptAER increases lagoons' capacity without increasing footprint

 

Project Information

Location:
Rocky Mountain House, Alberta

Project Type:
Municipal Wastewater Treatment

Completion Date: January 2014

Treatment Objectives

Design Flow:
3,333 m3/day (0.88 MGD)

Effluent Quality Requirements:
25 mg/L cBOD5

Project Background & Challenges

Nearly one kilometer above sea level, and one hour's drive West of the midpoint between Edmonton and Calgary, sits Rocky Mountain House. As its name suggests, the picturesque town sits in the foothills of Alberta's Rockies, on the shores of the North Saskatchewan River.

With its lagoons located in town, the town had explored the option of moving its wastewater treatment further away; however, when that became a longer-term consideration, Rocky Mountain House found itself in need of more capacity without running afoul of its limits, all while staying within its existing footprint using the infrastructure already in place.

The Nexom Answer

Rocky Mountain House decided on an optAER Aerated Lagoon System to an upgrade their existing 3-cell lagoon system. The optAER system was designed to meet 10-year hydraulic and loading requirements (combined flows at 3333 m3/day) and consisted of the following upgrades, technologies, and processes:

  • Retained existing lagoon system.
  • optAER fine-bubble partial mix aeration in existing cells 1, 2, and 3.

Site Construction

Upgraded System Performance

Since the lagoons have been upgraded, average monthly effluent cBOD5 and TSS numbers received from Rocky Mountain House over the course of a full year have been consistently below the targeted level.

Conclusion

With an upgraded lagoon system that will be able to handle the town's wastewater for the foreseeable future, both from the perspective of capacity and the ability to meet the necessary limits, the pressure to move the wastewater treatment facility out of town is reduced significantly. Rocky Mountain House is free to make long-term plans for 2023 and beyond with the comfort a smoothly-running, low-O&M optAER system provides.

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Waterton AB: optAER


Waterton, Albertanational park wastewater treatment facility allows for effluent re-use

Waterton AB: optAER


Waterton, Albertanational park wastewater treatment facility allows for effluent re-use

 

Project Information

Location:
Waterton Lakes National Park, Alberta

Project Type:
Municipal Wastewater Treatment

Completion Date: 2008

Treatment Objectives

Design Flow:
4,250 m3/day (1.12 MGD)

Effluent Quality Requirements:
25 mg/L cBOD5

Project Background & Challenges

Waterton National Park is located in south-western Alberta at the foot of the Rocky Mountains. It draws over 400,000 visitors a year with peak season in July to August. A lagoon based wastewater treatment, constructed in 1974, serves various business (hotels, inns, campgrounds) located near the heart of the Waterton village. An upgrade to this facility was completed in 2008 using Nexom's optAER® system.

The upgrades would allow for effluent reuse (golf course irrigation). The previous treatment facility consisted of two aerated cells followed by a storage pond. The cells were fitted with a coarse bubble aeration system which also installed in 1974. As it was, the system was unable to provide the stringent effluent requirements for re-use purposes.

The Nexom Answer

The design, equipment selection, and implementation were geared towards reducing the pathogenic content of the overall system effluent to safe levels for irrigation use. A UV disinfection system was installed (by others) at the back end of the process to accomplish this task. Nexom's challenge was to provide the high quality influent required by UV disinfection systems utilizing cost-effective technologies. The challenges were to:

  • Provide a complete mix aerated cell at the front end to meet Alberta Environment's (ANEV) requirements
  • Sufficiently aerate the treatment cells to reduce effluent TSS and cBOD5 to less than 20 mg/L and to digest settled solids
  • Implement a Poly aluminum Chloride (PAC) dosing system prior to sand filters to form removable flocs containing absorbed suspended pollutants
  • Implement a continuous backwash up-flow gravity sand filtration system to remove flocs of absorbed suspended solids

Nexom's optAER fine-bubble aeration system was used to replace an outdated coarse bubble system. An impermeable geomembrane floating baffle curtain was installed in the first cell to split it into two. The aeration in the first cell was designed to keep all solids in suspension to provide completely mixed conditions, and the second was designed as a partial mix aerated cell. Two continuous backwash up-flow gravity sand filters were fitted following the aerated ponds. A chemical injection pump to supply PAC was installed up stream of the sand filters. Chemical addition was necessary to achieve an effluent quality of 5 mg/L TSS during the algae growth season.

Site Construction

Upgraded System Performance

With the expansions and upgrades, the high effluent quality allows for re- use of the water for golf course irrigation within the park. This in turn reduced the loading discharged into the receiving waters. A third benefit was a reduction in surface water withdrawal from the Blakiston Creek (a bull trout spawning site). Prior to the upgrades, this creek was used to furnish water for irrigating the golf course.

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Buffalo NY: Deicing Fluid Treatment


Buffalo Airport Deicing Fluid Treatment

Buffalo NY: Deicing Fluid Treatment


Buffalo Airport Deicing Fluid Treatment

 

Project Information

Location: Buffalo Niagara International Airport, New York

Project Type: Airport Deicing Fluid

Completion Date: June 2008

Treatment Objectives

Flow capacity increase:
4,500 m3/day (1.2 MGD)

Maximum daily loading:
4,500 kg/day cBOD5 (10,000 lbs/day)

Effluent Quality:
30 mg/L cBOD5

Project Background & Challenges

As per regulatory requirements, the collection, containment and treatment of waste de-icing fluid are the responsibility of Airport management not individual carriers. In an article published in airport Improvement Magazine (July-August 2009), it was noted that Buffalo Niagara International Airport (BNIA) spent in excess of $13 million dollars over four years in an attempt to meet regulatory discharge requirements .Despite the substantial investment, the airport was not able to meet its obligations and "continued to exceed allowable levels".

Faced with mounting operational costs and discharge limit violations, BNIA was quick to recognize the need for a cost effective solution. The challenge was to develop a management plan that incorporated either off-site or on-site treatment to handle the seasonal variation in flow and BOD concentration.

If an on-site treatment system was to be constructed, it could not pose a risk to travelers' safety by drastically changing the environment in and around the airport. This meant excluding alternatives such as lagoons or open tanks which have the potential for attracting birds and other wildlife.

The Nexom Answer

Nexom, in collaboration with Urban Engineers, and Stantec designed a novel robust on-site treatment system that proved very cost effective in initial capital and O&M. The system can handle the high flush flow, low propylene glycol concentration of spring. During winter operations, the system is capable of handling the low flow high polypropylene concentration.

As an added advantage, the system was integrated with the stormwater management system to produce an effluent quality surpassing regulatory requirements on a year round basis.

The system comprises of vertical flow aerated gravel bed, a variation of Nexom's SAGR. Underground storage tanks are used to store and equalize flow prior to feeding the SAGR process. Grit removal chambers between the equalization tanks and the SAGR process remove particulate matter that could otherwise adversely affect process pumps and SAGR hydraulics.

The gravel bed provides required surface area for BOD reducing heterotrophic bacteria to attach and grow. Air introduced through Nexom's FBA® LINEAR aeration system provides a minimum of 2 mg/L disolved oxygen throughout the bed. The design and operation of the system is loading dependent as opposed to hydraulically limited. As a result, the process can handle a high flow at low BOD concentration (up to 1.2 MGD), a condition typically seen during spring thaw and summer operation, or the process can treat high influent BOD5 (>1000 mg/L) at low throughput to an effluent quality of 30 mg/L BOD5.

The bed is sized to ensure a balance between biomass accumulation and degradation. As a result, chances of long term fouling that would result in diminished hydraulic conductivity are minimized. Performance data of the vertical flow SAGR is as seen in the chart.

Site Construction

Upgraded System Performance

The data plotted in the chart shows performance of the BNIA treatment system over the course of approximately six (6) months. The loading to the system is highest during the coldest of the winter months (i.e. December – March), which is to be expected. Of interest though is the fact that loading during the remaining months is fairly low. Despite fact that bacteria are essentially starved for a better part of year, a vibrant and active biomass is maintained within the system to treat peak loading to 95%+ removal. The extent of biomass reduction in the summer is due to insufficient food supply and predation.

Figure 1

Figure 1

Conclusion

The SAGR is not just a simple, effective post-lagoon nitrification system, it can also bring that same efficiency and simplicity to airports looking to treat the BOD-rich aircraft deicing fluid.