Letting wetlands do the work of water treatment

Water is the lifeblood of Alberta’s communities, big and small. It keeps us alive and keeps us clean, washing away the dirt and waste from our daily lives. But down the drain is only the beginning of its journey. Water is our most precious resource, and we owe it to ourselves, to our neighbours and to our environment to make it clean again.

With a growing population and a changing climate, this is no small task. Wastewater and stormwater treatment can be expensive, involving advanced technologies and large facilities to meet changing demands. However, the future of water management might not be made of concrete and metal, but of soil, plants and small armies of microbes.

In natural ecosystems, sediment, excess nutrients and pathogens are removed by natural elements that make up our wetlands. If wetlands are the model of effective water treatment, why not put nature in control of our wastewater and stormwater? Innovators right here in Alberta are doing just that. From stormwater in a Calgary neighbourhood to wastewater in rural Clearwater County, this nature-based treatment approach has been refined and adapted to tackle water challenges in communities big and small.

Stormwater is a hidden resource in the rough

It’s a summer rainstorm over the city. Dark clouds roll across the sky, and in an instant, water is running down gutters, over curbs and along the street before escaping into a storm drain. Stormwater systems protect homes, businesses and other infrastructure by directing rain and meltwater into constructed ponds. These ponds could, in turn, serve as a water source for irrigation and other community uses, reducing demand on drinking water. However, stormwater designated for reuse must first meet stringent quality standards. Along its journey, stormwater picks up dirt, fertilizer, oil, paint, human and animal waste, and other contaminants, which must all be safely removed.

The solution is usually a mechanical water treatment plant, but such facilities are incredibly expensive to construct and operate. They have to be ready to handle a worst-case scenario: a rush of water filled with debris and sediment after a large storm. This means an oversized facility which will only be used a few months out of the year.

If the components of a natural wetland could be replicated within a stormwater pond, it could potentially provide effective water treatment at a lower cost, enabling more opportunities for stormwater reuse while beautifying urban spaces. A creative treatment system in Calgary has not only shown that this is possible but also served as a springboard for the development of similar projects within the province.

Transforming a stormwater pond into a functioning wetland

The Stormwater Kidney® at Dawson’s Landing in the community of Chestermere. After initial settling in the Nautilus Pond® (pictured at the leftmost part of the complex), stormwater flows into the large main pond body. The treatment wetland can be seen at the far end of the complex.

Source2Source, a Calgary-based engineering firm, is a longtime innovator of nature-based solutions for stormwater. It all began with a technology called the Nautilus Pond®, which has a passive design that encourages incoming stormwater to flow around the pond’s perimeter, keeping new and old stormwater separate for better sediment removal. While the Nautilus Pond was a relatively humble technology, its success gave its designers a whole new perspective.

“Once we did the Nautilus Pond®, we could see that we were actually starting the process of building a natural wastewater treatment system,” says Cory Albers, hydraulic systems engineer and Source2Source co-owner. “We could see the world from a completely different vantage point and ask, ‘what would the next logical step be in the technology evolution to achieve greater outcomes?’”

The opportunity to pursue this evolution would come in the form of a development project in northeast Calgary. Development firm Triovest had planned to create a new business park in Calgary’s Saddle Ridge neighbourhood, but managing stormwater proved a difficult challenge. Saddle Ridge drained into Nose Creek, a protected watershed which is subject to stringent guidelines on stormwater discharge. Normally, this would necessitate an expensive stormwater pond retrofit for the development to move forward. Seeking a better solution, Triovest and Idea Group, a civil engineering consultant on the project, sought the services of Source2Source.

The Saddle Ridge Stormwater Kidney® design: stormwater enters the pre-treatment area at top-right where primary settling occurs before entering the main pond body at bottom-right. A small recirculation pump at the bottom-left portion of the main pond sends water into the treatment wetland. The treated water may exit via an outlet at bottom-left, or recirculate back to the main pond body.

Source2Source proposed a technology that they dubbed the “Stormwater Kidney®.” Its design would not only remove sediment but recirculate the water through a biofilter – similar to the action of a living kidney. The vision was for a self-sustaining treatment wetland.

The development at Saddle Ridge offered the chance to put the Stormwater Kidney® to the test, but Source2Source would need Triovest and the City of Calgary to get on board. Funding from Alberta Innovates was a key factor in building confidence with the partners.

“The contribution was profoundly transformative, not only for my company but for the industry,” says Albers. “The funding helped de-risk the project.”

Construction on the site began in 2019 and was completed in 2020. The design uses all natural materials with two low power circulation pumps and one irrigation pump. Incoming stormwater first enters the pond and is pumped to a horizontal flow wetland before entering a treatment wetland.

The treatment wetland includes a vertical flow biofilter made up of layers of sand and woodchips. Contaminants, human pathogenic organisms and indicator organisms like E. coli are captured and consumed as the water slowly passes through the biofilter medium, which is home to an entire ecosystem of beneficial microbes. Like in a natural wetland, the living plants and microbes break down and absorb excess nutrients, removing them from the water. But it can take time for the young ecosystem to find a stable rhythm.

“I knew this in my head, but I needed to learn this in my heart too: you can’t expect natural systems to be established right away,” says Albers. “Normally, you expect the count of certain microorganisms to drop by the time you get to the bottom of the biofilter, but instead we got amplification in the first year. It’s like doing an experiment on gravity and finding everything falls up.”

Thankfully, by the second year of operation, the system had achieved equilibrium. It’s the natural rebalancing action of this ecosystem that is the key to its function.

“Another engineer may have 500 sensors in their conventional treatment system, but our systems have a trillion sensors,” says Albers. “Because every little bacterium, water beetle, worm, dragonfly and plant shoot has its own sensor system. And those sensor systems are uniquely and purposefully evolved to make the most of that environment.”

The end result is water clean enough to meet provincial requirements for stormwater reuse – and indeed cleaner than the output of many modern treatment plants around the world.

The Stormwater Kidney® clearly demonstrates that a nature-based solution can provide high-quality stormwater treatment and beautiful urban spaces at a low cost to municipalities. A win-win for people and nature, and an approach that has snowballed into other naturalized wetlands.

Inspired by the potential of the Saddle Ridge pilot, the City of Chestermere approved two enhanced versions of the Stormwater Kidney®design for the community of Dawson’s Landing. The combined outcomes from Saddleridge and Dawson’s Landing in turn built the momentum needed for additional projects in the City of Calgary and beyond.

“This all started with the seed, which was funding from Alberta Innovates. Without it, none of this momentum would have been possible,” says Albers.

As the Stormwater Kidney® design evolved across each new iteration, it soon became clear that constructed wetlands could be adapted for another challenge: wastewater treatment.

Wastewater: a growing problem for growing communities

When you flush your toilet or drain your sink, where does the water go? If you live in one of Alberta’s many rural communities, the answer may be a wastewater lagoon. Compared to a conventional treatment plant, a wastewater lagoon is a simple and cost-effective option. Sewage enters a large, constructed pond – the lagoon – where bacteria and algae begin to break down the waste products.

While wastewater lagoons are more affordable for small communities, they come with some key drawbacks. With wastewater left open to the surface, bad odours can drift to nearby residents. The lagoon’s microbial community is less resilient than that of a natural wetland, and therefore is unable to break down the waste completely. Often, some additional chemical treatment is needed before water can be released into the environment. These challenges only worsen as communities grow beyond what their lagoon system was designed to handle. As water quality standards become more stringent, many aging lagoons are no longer up to snuff.

For communities that have outgrown their old lagoon, upgrading to a mechanical treatment system is a steep jump in complexity. Where they once enjoyed a largely hands-off system, they now face the prospect of significant upfront construction and maintenance costs, followed by the additional hurdle of attracting and retaining a certified operator. This can put upgrades out of reach for small communities who desperately need them.

These factors and more put rural and remote communities at the forefront of the province’s water challenges. But a new wastewater project in west central Alberta which draws on the Stormwater Kidney® technology foundation is showing that this nature-based approach could once again help bridge the gap.

Could this nature-based solution be the answer in Clearwater County?

In the shadow of the Rockies between Banff and Jasper, Clearwater County lives up to its name with impressive freshwater features like Siffleur Falls and Abraham Lake. The large rural municipality covers an area of nearly 19,000 kilometres squared and comprises over 12,000 residents.

The county owns three wastewater lagoons which serve the hamlets of Leslieville, Condor and Nordegg. However, the aging lagoons at Leslieville and Condor have struggled to keep up with a growing population and no longer meet provincial operating standards for water quality. The county was stuck with a difficult choice: continue with their existing, insufficient lagoon system, or upgrade to a mechanical treatment system at great financial cost. What they needed was a third option that could fill the gap.

The County soon began working with Magna Engineering Services. Magna was no stranger to water treatment challenges – they had partnered with Source2Source to deliver both Stormwater Kidney® systems at Dawson’s Landing, and their Director of Innovation, Anton Skorobogatov, had started his career at Source2Source working closely with Albers. To meet the needs of Clearwater County, Magna proposed a naturalized treatment facility that could provide better results than the lagoon with minimal operating costs. Its design would resemble the naturalized wetlands of the Stormwater Kidney® – but specifically adapted for wastewater.

“They are different in the way they are designed, but both projects are benefiting from the notion that when you have some form of soil, plants and miroorganisms that you put together, it can provide benefits to having clean water,” says Skorobogatov.

The Magna Biofilter Wetland System under construction at Leslieville.

With funding support from Alberta Innovates, construction of the Magna Biofilter Wetland System began in 2022. This included the wetland itself as well as a new headworks building to house a micro-screening unit. Raw wastewater from the community of Leslieville, once pumped directly into the lagoon, now enters the screening unit where bulk solid waste is removed. The remaining liquid waste then enters the wetlands portion of the system. Unlike an open lagoon, all of the action happens below the soil surface, with no standing water.

The first stage of the wetland portion is a vertical flow biofilter. Layers of sand, gravel and drain rock are blanketed by a top layer of mulch. Wastewater is piped in just under the surface so that it can drain freely through each of the layers below. This part of the wetland is oxygen rich, creating ideal conditions for the kinds of microbes that can break down organic compounds. A mixture of willow and herbaceous plants are planted at the surface of the biofilter. Their roots interact with the microbes in the soils below to produce a more diverse and resilient ecosystem.

Once the wastewater reaches the bottom of the biofilter, it is pumped into the second stage of the wetland. In this stage, the wastewater flows horizontally through fully saturated drain rock and gravel. This section is oxygen poor, fostering a different community of microbes that can break down the waste more fully. Bacteria convert nitrogen-containing compounds to harmless nitrogen gas, which bubbles up to the wetland surface.

Across the entire wetland system, microbes are the star of the show. The two stages – one oxygen rich and the other oxygen poor – foster different communities of microbes, achieving a much more complete breakdown of the waste.

The system is also designed for cold Alberta climates. The freeze-thaw cycle can slow down and disrupt the action of microbes in a regular lagoon, but in the biofilter wetland, the surface layer of mulch insulates the microbes from frost. This keeps them safe and snug so they can keep hard at work even in the cold.

“We are expecting to see a really consistent performance year-round, because we don’t really overheat in the summer, and we don’t lose much heat to the surrounding environment in the winters,” says Skorobogatov.

Another advantage of the wetland system is its effectiveness at removing pathogens. By filtering the wastewater through many layers of sand and rock, most pathogens like E. coli are removed by the time water exists the system.

The result is water that is far cleaner than what a lagoon can achieve and all without the use of added chemicals. But is it enough to meet provincial water quality standards? The results so far have been promising.

“It is somewhat nerve-wracking to see the first set of results,” says Skorobogatov. “These natural systems typically take some time to establish, so I was expecting a period of average results working towards better outcomes as that microbial community establishes. But we were able to see the transformations – that complete nitrogen breakdown – right away.”

Now that the pilot system is operational, the team will continue to monitor its performance, with hopes it will earn the confidence of regulators.

“Currently we’re working on the monitoring program to make sure the system is performing as it needs to be,” says Skorobogatov. “Alberta Innovates funding is allowing that to happen, as it’s not something that a typical municipality would be able to cover.”

Like with any natural wetland, the plants will take time to grow and mature. Right now, small seedlings dot the surface of the mulch, but over time the site will grow into lush habitat for birds and pollinators.

“[In 2024], I fully expect there to be a willow grove and a meadow,” says Skorobogatov. “It’s coming together nicely that everyone can see it’s not just a wastewater treatment facility, but it’s also going to be this effective habitat and homegrown ecosystem.”

Sharing the vision of a nature-based future

Nature-based solutions emerge from humble beginnings. It can be hard to look at soil dotted with tiny seedlings and trust it will flourish into a thriving wetland. Without committed partners ready to take the plunge, naturalized wetlands are dead in the water.

“We had to make sure to bring everybody on board, in terms of what it is, how it’s different, what are the benefits and why don’t we go conventional,” says Skorobogatov, recalling initial community engagement on the Magna Biofilter Wetland System.

Building relationships and getting buy-in from partners was equally important for development of the Stormwater Kidney®.

“For a technology to develop and succeed and evolve, those broader pieces end up being determinative,” says Albers. “How did momentum build? It turned out that the City of Calgary doing it and then another community doing it created a positive feedback loop – which was critically important in the eventual adoption cycle.”

Albers now aims to carry that momentum well beyond Alberta. Access to safe drinking water is something many Canadians take for granted, but effective water treatment is a luxury in many parts of the globe. A nature-based approach could offer vastly improved outcomes at a low cost.

“The Alberta Innovates funding truly was the start of much bigger things, and now I’m trying to bring this to other parts of the world and improve the lives of potentially hundreds of millions of people,” says Albers. “When we can produce safe water from otherwise contaminated water, that’s profoundly important.”

Meanwhile, Magna and Source2Source will continue to work together to develop and deliver nature-based solutions here at home.

“The stars are aligning for nature-based solutions,” says Skorobogatov. “And its really exciting to be in the province at this time and have the support to move forward.”

Learn more about Alberta Innovates’ Water Innovation Program.

This article is part of Making Waves, an annual Alberta Innovates publication highlighting water solutions we support. You can read more stories from this issue below.