Learning a Lesson from Nature
by Sean Kelly and David Redwood

An innovative system uses living organisms to treat waste in rural Nova Scotia...and transforms a community at the same time.

Photo © Sean Kelly

“Build it and they will come.”

On the banks of a river that ebbs and flows with the daily tides of the famous Bay of Fundy, the newest tourist attraction in the picture-postcard village of Bear River has lured over 8,000 visitors from around the world. “It's been a nuthouse, just herds of people,” says manager Carol Armstrong – welcome relief to a rural Nova Scotian community hard-hit by a fisheries crisis and the closing of a nearby military base. Local inns, retail stores and the town's two restaurants have all reported big increases in business.

So what's generating all the excitement? A theme park? The world's largest lobster statue? A casino?

Would you believe a sewage treatment plant?

Bear River (population 881) is home to an innovative wastewater treatment facility that relies on living organisms to do the dirty work. Bear River Solar Aquatics Wastewater Treatment Facility is a glass structure that looks like an ordinary greenhouse. But inside, plants, snails, protozoa and algae – fueled by the power of the sun – are busy breaking sewage down into clean water that flows into the tidal river. What the tourists are seeing in Bear River is a 'living machine,' an award-winning example of designing like a natural ecosystem.

It's something more people need to see, as too many of us are linear thinkers on this spherical planet. The human-made industrial world extracts resources from the natural world and transforms them into products, producing pollution and waste in the process. Many of these products ultimately end up discarded as yet more waste. Linear economics takes too much from the Earth, and puts too much pollution back in.

Without a doubt, the modern economy makes a dazzling array of consumer goods, some of them extraordinary, many of them unattainable by the world's majority. But in the pursuit of short-term profit, we are using up or destroying our 'capital' – in this case the eco-capital of the Earth's resources – rather than living off our 'savings' through, for example, the careful use of renewable resources. As well-known ecological economist Herman Daley aptly puts it, “We are treating the Earth like it's a business in liquidation.”

Yet the Earth is a source of inspiration when looking for solutions: its ecosystems are, after all, circular, renewable, no-waste economies powered by the sun. Waste from one process becomes the raw material for another – nothing is thrown away. Nature is living testament to the truth of the adage “waste not want not.” In Bear River, even human waste is a resource that can be put to good use, if you think like an ecosystem.

Stepping through the sliding glass doors of the sewage treatment plant, one expects an odorous welcome. Instead, you are greeted with the humid, verdant-smelling air typical of any large greenhouse. Rows of clear-sided tanks are topped with an assortment of colorful vegetation: floating aquatic plants such as duckweed, water hyacinth and mint, and non-aquatic varieties such as willow and dogwood suspended by netting, their roots continuing down into the nutrient-rich mixture. Snails cling to the inside of the transparent tanks, sucking up algae growth that blocks essential sunlight from reaching life in the water. A large indoor 'pond' contains more plants, including banana and fig trees.

Plant manager Carol Armstrong doubles as an enthusiastic tour-guide. She walks a constant stream of visitors – many who show up unannounced, curious about this engineered ecosystem – through the voyage the waste takes before it flows into Bear River. Pumps first inject fine air bubbles into an underground tank of blended sewage and septage. When combined with the bacteria Armstrong adds daily, this sewage becomes, quite literally, food for consumption. It enters the five-foot high tanks where bacteria, algae and protozoa are at work detoxifying many harmful microbes in the water. These organisms find a habitat on the roots of the larger plants suspended on the water's surface, which in turn absorb toxins not broken down by the smaller species.

“We tried some water lettuce and semi-tropical plants,” Armstrong says, sounding more like a farmer than a sewage treatment plant operator, “but most of them were overcrowded by other plants. Local varieties seem to do better than tropical ones so next spring I will be planting a lot of local stuff. I am going to have fun with this.” The plants are currently composted but she has plans to sell the ornamental flowers once more residents are hooked up to the plant; the facility is only operating at one fifth its capacity of over 50,000 liters of waste water a day.

Gravity moves the stream of wastewater through the tanks, an indoor pond, and finally to a small engineered march. There, grasses and irises absorb remaining toxins. A screen removes the last of the suspended solids, and an ultraviolet light completes the process by disinfecting the water. The final chemical-free product is discharged into the river often clean enough to drink. It's a world of difference from most conventional methods of treating sewage which, while sometimes using a limited number of organisms to treat sewage, are not symbiotic ecosystems and have to resort to chemicals like chlorine to clean the water. And, making the natural treatment facility seem too good to be true, it is less expensive to build and maintain.

Dr. John Todd, the inventor of Bear River's “living machine” process, has long advocated this kind of ecological design as the “application of natural relationships to human need and to the integration of humanity with the larger natural world around us.” His ideas go beyond just mimicking nature's cyclical model – he advocates using living organisms themselves as the basis for engineering. For twenty-five years, he has researched living species that can form durable, self-designing and above all, useful ecosystems.

Ecological design “grows out of the place itself – what's there now. The climate, biota, geology, topography. Whether it is urban or rural, First World or Third World...in fact, the opportunities for this in the tropics are just as great, or greater, than in the North.” And when you begin the work, you carry a very unique set of tools. “A wonderful example is in one of our living machines, where we use an Amazonian Catfish which is very effective at ingesting sludge. How many conventional engineers would think of having an Amazonian Catfish in their tool kit?”

“Unlike a dead machine, a living machine's parts are primarily live things. Its structure or its skeleton is inert obviously – tanks, greenhouses, things like that – but its [inner workings] are thousands or hundreds of thousands of parts made up of thousands of species. What they have is the ability to interact with each other, to self-organize, self-design, self-repair, self-reproduce.”

Industry, as well as towns like Bear River, is beginning to recognize the economic benefits of living machines. “We go to something like a brewery or food processor and say: 'We can take a problem that is quite troubling or costly to you, we can clean it up and we can also create a secondary by-product – you can now grow food as a spin-off of the original activity. We are able to show many companies that they can comply with environmental standards and actually pay for the living machines in sometimes as short a period as two years.”

The lessons of cyclical thinking also extend to the broader economy. Maximizing the use of non-renewable resources through durable design, reuse and recycling is one application of the philosophy. A more imaginative step is an industrial park where many businesses are integrated, symbiotic members of one common closed-loop system. The machine parts remain inert, but the natural cycle is adopted. A company's waste becomes a needed input in a second company's industrial process. The heat created in the manufacturing of one product fuels the energy needs of another.

Products can also be designed for their entire life cycle. The Environmental Protection Encouragement Agency of Germany promotes what they call Intelligent Products; for example, products that are created from sustainably-managed renewable resources in a way that when returned to the earth, they biodegrade without toxic effects. “Durables” such as cars, televisions and refrigerators would not be sold but rather licensed from a company. The product would always belong to the original manufacturer, to be constructed, used and returned within a closed-loop system. When a company knows their product will end back on their doorstep yet they cannot legally throw it away, decomposition, reuse and refurbishment soon become central pillars of design.

Of course, these ideas do not address a primary cause of our growing ecological crisis: over-consumption. And Dr. Todd would prefer to see more of our economy incorporate natural, living organisms. “Industrial ecology is a little artificial, but when industry gets to the point of exchanging energy and nutrients, then it does become like ecology – in the sense that there is mutual sharing going on.”

“Humans have to learn to do that. I do foresee a time when communities are designed as ecosystems: in a sense very large living machines within which people live and work, do their civic function, their education and their manufacturing.”

Back in Bear River, this new thinking is taking root. Their living machine enjoyed extraordinary grassroots support, and the community continues to build on this spirit of cooperation and pragmatic optimism. The town's citizens have transformed a closed school into an arts centre and a recently abandoned bank building into a community health clinic. As Carol Armstrong says, “This place is magic.” You can almost smell it in the air.

Sean Kelly works with CUSO Atlantic. David Redwood, a freelance writer living in Halifax, works with youth and environmental groups. This article was published in 1996.

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