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A Living Machine


A living machine
Designing industrial systems to behave like natural systems may be one way we can
help to ‘green’ the planet. Sean Kelly and Dave Redwood investigate an experiment
in rural Nova Scotia where there is more than meets the eye – and the nose.

The industrial system is based on a linear model which assumes natural resources have no value in themselves. The result is an economy which processes large amounts of resources into waste as quickly as possible. A green economy would question superfluous consumption and seek to ‘close the loops’, to mimic cyclical natural systems so that waste becomes food, nothing is thrown away and symbiosis replaces competition.

Bear River, Nova Scotia, situated on the banks of the famous Bay of Fundy used to be a relatively quiet place. No more. ‘It’s been a nuthouse, just herds of people,’ says Carol Armstrong, manager of the village’s newest tourist attraction. Local inns, retail stores and the town’s two restaurants have all reported big increases in business.

So what’s generating all the excitement? Believe it or not visitors are flocking to the picture-postcard village (population 881) to gawk at a sewage treatment plant. And not just any sewage plant. The Bear River facility is an innovative wastewater treatment plant that relies on living organisms to do the dirty work.

What goes around comes around: floating vegetation feeding on sewage in the Bear River.
all photos by SEAN KELLY

Nestled in a river valley between steep hills next to the town’s windmill, the glass structure looks like an ordinary greenhouse. Inside it’s a different story: plants, snails, protozoa and algae – fuelled 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.

In Bear River even human waste is a resource that can be put to good use. Stepping through the sliding glass doors, 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 colourful vegetation: floating aquatic plants like 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 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 leads a constant stream of visitors through the voyage the waste takes before it flows into the river. Pumps first inject fine air bubbles into an underground tank of blended sewage. 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 local varieties seem to do better than tropical ones so next spring I will be planting a lot of local stuff’. The plants are currently composted but she has plans to sell the ornamental flowers once more residents are hooked up to the plant. At the moment the facility operates at just a fifth of its capacity of 50,000 litres a day.

Gravity moves the stream of wastewater through the tanks, an indoor pond and finally to a small engineered marsh. 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 clean enough to drink. It’s a world of difference from most conventional methods 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. As an added bonus the natural treatment facility is also 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’. From Ocean Arks International, the Massachusetts-based research organization he established in 1980, Todd has become a modern-day prophet of the wide-ranging benefits of ecological design.

‘You design a living machine with a whole range of ideas in mind,’ he says. ‘You could be designing it to treat waste water as in Bear River. Or you might be designing it for the production of foods; for the generation of fuels; for heating buildings in a cool climate; to integrate industrial activity with human settlement and agricultural activity.’

Ecological design, Todd believes, ‘grows out of the place itself – 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.’

'This place is magic.' Manager Carol Armstrong clutches a beaker of clean water, the end result of the 'living machine' treatment process.
all photo's by SEAN KELLY

Industry too, Todd says, is beginning to recognize the economic benefits of living machines. ‘We can go to a brewery now, for example, and tell them we can take a problem that is quite troubling or costly and 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, sometimes in 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, re-use 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. The heat created in the manufacturing of one product fuels the energy needs of another.

In the Danish city of Kalundborg in the early 1970s a manufacturer decided to locate a large plant in the town’s industrial park to take advantage of a nearby refinery’s waste fuel-gas. The successful re-use of this by-product, which until then had simply been burned off, sparked other plant managers and some city officials to look into other efficiencies. They discovered there was tremendous heat disappearing up the stacks of the Asnaes coal-fired power station. Soon two companies and thousands of residents were heating their buildings with Asnaes steam. One of these companies, they also discovered, was drowning in a nitrogen and phosphorous-rich sludge. Soon nearly 1,000 nearby farms were welcoming a reliable supply of fertilizer from the industrial park. Over the years, manageable and easily understood arrangements such as these reinforced each other – to the point where seven industrial plants and thousands of farmers and city-dwellers are now connected in a web of exchanges involving an estimated three million tons of material annually.

Elsewhere products are also being designed for their entire life ‘cycle’. The Environmental Protection Encouragement Agency of Germany promotes what they call Intelligent Products – products that are created so 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, re-use 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 John 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 enjoys extraordinary grassroots support and the community continues to build on this spirit of co-operation 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 and Dave Redwood live in Halifax, Nova Scotia. where Sean is editor of the Sustainable TIMES and Dave works with youth and environmental groups.    

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©Copyright: New Internationalist 1996

New Internationalist issue 278 magazine cover This article is from the April 1996 issue of New Internationalist.
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