Doing it Mother Natures way
By Matthew Van Dongen

Used for decades in warmer climes, constructed wetlands are only a new technology in the sense that they haven't been used much in Canada, where frigid winters mean wetlands can only function for five or six months at a time.

Wetlands — both natural and constructed — act as nature's filter for wastewater.

A typical wetland is filled with hardy, water-loving plants such as cattails and the common reed, both of which suck up nutrients present in wastewater.

But more importantly, the roots systems of these plants create an interconnected web — or biofilm — within the wetland, attracting colonies of bacteria that climb all over each other to feast on the nutrients wastewater provides.

At the Dignard farm, a series of wetland cells — compartments filled with plants and lined with clay to prevent water from escaping — provide relatively fast and effective treatment for farm's liquid runoff.

The system starts like a gigantic version of a typical household septic system, with Dignard's original holding lagoon acting like a septic tank.

In this "tank," while solid waste settles to the bottom, wastewater is partially treated by aerobic and anaerobic microbes, bacteria that thrive in either air-filled or airless environments.

But in contrast to a regular septic system, where partially-treated wastewater is dispersed through channels of a gravel-filled septic bed, the liquid in Dignard's "tank" is pumped through series of wetland cells before finally making its way into the environment.

A successful technology

Dignard, a man of few words, seems almost effusive in his praise of the system. "It saves a lot of time and money for me, it gets rid of 60 per cent of the runoff, no problem."

"Its been about five years, and it's still working good," he adds. "We're pretty happy with it."

So is Rhonda Boutz, a water quality technologist with South Nation Conservation Authority, a caretaker organization for the South Nation River watershed just outside of Ottawa.

It was SNC that partnered with Dignard and various government and private agencies to test the pilot project in 1994, and after three years of observation, the project was pronounced a success.

Boutz says the water coming out of the wetland system consistently meets provincial water quality standards. As a result, the Dignard site has become the poster child for wetland success in the region.

But if you haven't seen too many constructed wetlands in your travels around Ontario, you're not alone. 

Despite the proven scientific track record of the all-natural treatment method in the United States and — to a smaller extent — in Canada, constructed wetlands haven't been put to widespread use in Ontario.

There are a few reasons why this is so.

Size does matter

For agricultural purposes at least, one problem is size. The Dignard wetland covers three acres, and Boutz says many farmers can't afford to give up that much land merely to help out Mother Nature.

Another, more predictable problem is price. While the Dignard wetland rang in at about $40,000, Boutz says the prices can vary widely depending on the site conditions.

A wetland would cost significantly less at a farm with a soil structure that allowed the wetland cells to be lined with clay, for example, than one where the soil structure required the installation of synthetic liners.

Despite these problems, Boutz remains optimistic about the future of wetlands, and not just in the agricultural context. 

"These things can be used for a a variety of purposes — golf courses, private and municipal wastewater," she says. "I think they have a lot of potential."

New solutions, new uses

Finding ways to increase and exploit wetland potential is the job of Anna Crolla, a senior researcher at the Ontario Rural Wastewater Centre in Alfred, Ontario.

Crolla and others at the centre are researching ways to solve problems associated with natural wastewater treatment, such as creating smaller but equally effective wetlands.

One factor the centre is experimenting with is shape. For example, Crolla says some studies show longer, narrower wetlands are more effective in wastewater treatment.

Another way to improve treatment within a smaller area is aeration — pumping of extra air into the system, which gives avaricious bacteria extra incentive to chow down.

As an interesting twist, Crolla says researchers are trying out windmills in the aeration process, in an attempt to keep the entire process natural  and cost effective.

Crolla says the use of constructed wetlands is especially suited to agricultural needs. "Farmers like the systems, because there's not a lot of operation,' she says. "After you install the system, you pretty much leave it alone."

But like Boutz, she maintains the use of the technology isn't limited to cleaning up after farm animals.

There is also a movement within Ontario to use the technology on a municipal level. A project in Alfred, some 70 km east of Ottawa, is one such example.

Here, Crolla says they are experimenting with the use of a wetland as a "polishing step" for the contents of the village's sewage lagoons, two 35-acre holding cells that contain the village's wastewater.

Normally, the sewage lagoons serve as a huge, open septic tank, discharging a certain amount of the "treated' effluent into a nearby brook once a year.

But with the addition of five acres of wetland, the discharged liquid gets additional treatment courtesy of cattails and their bacterial retinue.

Although the wetland can only handle about 15 per cent of the village's wastewater, it still improves water quality and is cheaper than expanding the size of the already enormous lagoons.

Crolla says if the Alfred project is successful, it could pave the way for other municipalities to adopt similar installations, but she admits the application of environmental solutions to the treatment of human wastes has its own challenges.

"It's a little different in that case, people are more hesitant — they feel like there aren't as many controls in place as there would be with a typical treatment plant," she says. "There's definitely more reluctance to accept change when it comes to human waste."

Money matters

These arguments definitely catch people's attention, he says, estimating Lissom gets an average of one request a day to learn more about the prospective new technology.

So, with a well-marketed idea grounded in good science, and plenty of interest, how many wetlands does Lissom install for private owners in the space of a year?

"One system," is the deadpan reply. "Not one system a year — just one system. Period." 

While the price of an average septic system and an average personal wetland aren't that far apart- $4,000 versus the $7,000 Lissom charges — he says this difference is enough to quash the enthusiasm of many potential customers. 

On top of that, Lissom recommends that wetland owners have a landscape technician come in once a year to ensure plant life and water quality are still up to scratch, which tacks on another couple hundred dollars annually.

Ultimately, Porritt says people need motivation to spend more money than they have to, and he thinks stricter legislation is needed to drive this change. 

"When requirements for regular beds become more stringent, typical beds will need more treatment," he says. "People will slowly realize  'hey, this isn't working I need something better.'" 

But stricter legislation is something that is lacking in many areas of wastewater treatment in Ontario, including agriculture.

Boutz says while the Ontario government has a wide range of recommendations set out for farmers to protect the environment called 'best management practices,' few of these recommendations have the force of law behind them.

South Nation Conservation promotes best management practices through their Clean Water Program, which gives out grants to farmers willing to change their farming practices for the better.

But there are still manure piles, exercise yards and improperly built storage containers leaching nutrients directly into the watercourses throughout the provinces, says Boutz, and only provincial legislation is likely to change this.

Playing by new rules

Sharon Johnston, co-ordinator of standards development with the Ontario Ministry of Agricultural, Food and Rural Affairs, says this legislation is coming.

Johnston is working on Bill 81, currently winding its way through the provincial legislature, which deals with nutrient management in Ontario — specifically, the hauling, spreading and storage of biosolids, or human and animal waste.

She says the new bill is meant to deal with the many issues surrounding agricultural biosolids, but adds the draft regulations will not be out before January at the earliest.

This means specific details, such as whether or not alternative methods will receive extra funding or attention, won't be available for some time.

"Eventually we'll come to the point when people will realize you can't just stick your sewage in the ground and forget about it."

Crolla, for one, remains positive on the future of constructed wetland use. "I do think for agriculture at least, there will be stricter legislation. Once that is in place, people will be taking a closer look at things like wetlands."

Whether or not new legislation will force people to consider alternative wastewater treatment remains to be seen. But Porritt thinks stricter controls will bring about an attitude change that is an important start.