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Earth's New Season by Guy Dauncey
Biologically, we’re mammals and for all but the last 2,000 years, we’ve
dropped our dung on the land, as other mammals do. I had first hand experience
of this when I lived in the village of Bambadinka, in southern Senegal, where
the morning routine involved an excursion into the bushes. Wild pigs live in those
bushes and they have a morning routine too. It’s all very healthy, and it
ensures that nature’s wastes are recycled. It also explains why pork is
taboo among Muslims. I must admit to the occasional concern when a pig was a little
impatient and wanted his breakfast warm, but overall, the system worked well.
The village was small and the bush was big.
Then along came the Romans, who built incredible aqueducts and used the water
from their baths to flush their sewage into local rivers or seas. When the Romans
lost it to the Goths, sewage disposal reverted to the pigs until the Victorians
rediscovered the joys of piped disposal, encouraged by some nasty attacks of cholera.
In other words, sewage treatment as we know it is only a couple of hundred years
old. So let me pose the question: how will we deal with our sewage in 3003 AD?
In Victoria, we pipe it untreated into Juan de Fuca Strait, where the cold currents
dilute and disperse it. In Vancouver, we let the solids settle through primary
treatment and pipe it into the Strait of Georgia, PCBs, drugs and all. No wonder
the orcas are having a hard time. In 1999, the Sierra Legal Defence Fund’s
staff calculated that we dump over a trillion litres of untreated or partially
treated sewage into Canada’s rivers, lakes and oceans each year, enough
to cover the entire 7,800 kilometre length of the Trans-Canada highway to a depth
of nearly 20 metres. From sea to shining sea it takes on a whole new meaning as
a metaphor for the wastefulness of our culture.
In Kelowna and Penticton, where they take their drinking water from the lakes
they dump their sewage into, they use tertiary treatment, but it still leaves
water-soluble drugs and hormones. In Tucson, Arizona, they dump their treated
sewage into the local aquifer, and re-use it for irrigation. All of these systems
use enormous quantities of water and require that the solids are dumped, usually
in a landfill. Is this the best we can do? There are two exciting departures from
these wasteful ways and a third that is coming into view.
The first is the composting toilet, which uses no water at all. It separates your
pee and converts your breakfast into wonderful compost that can be used on the
garden. How more natural can you get? Contrary to what many people believe, composting
toilets are not illegal. It’s the greywater from sinks and showers that’s
the problem, since greywater treatment systems are not designed for urban situations
and are frowned on by health authorities.
The second is John Todd’s ecologically designed living machine, which turns
sewage treatment on its head. Instead of letting the solids settle, it keeps them
moving and feeds them first to algae, then to plants such as water hyacinths and
finally to fish. The plants are harvested and composted and the clean water used
for irrigation. There are dozens of systems around the world, from Providence,
Rhode Island, to Errington on Vancouver Island. This is biomimicry at its best.
(www.livingmachines.com; Kim Rink, 604-882-2199).
The third possibility involves the use of sewage to generate hydrogen. Researchers
at the University of Warwick, UK, have developed a membrane reactor that can gasify
sewage and extract 95 percent pure hydrogen from its water and biosolids. The
system is very energy efficient and does not depend on a fossil fuel such as natural
gas to produce the hydrogen. They are now working with a $5 million grant from
the European Union to develop a larger prototype.
Maybe this is the answer. Maybe our future sewage treatment plants will be beautiful,
flower-growing, solar aquatic bird sanctuaries that produce hydrogen to run our
cities. No more waste, no more pollution. Just SHIT - solar hydrogen intelligent
treatment.
Guy Dauncey is the author of Earthfuture: Stories From a Sustainable World
(New Society Publishers, 1999) and other titles.
Read part 1 of Journey into Gold (Common
Ground, June 2003)
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