Posted by Big Gav in waste
Crikey has an article on using human waste - A serious story (with a few jokes) about putting our waste to work.
Early in human culture and particularly in agricultural societies, he says, humans mimicked much animal behaviour when it came to using excrement as a resource. In South East Asia, cow pats were dried and burnt as fuel, while in the early 1700s, in Tokyo (then called Edo), homeowners and building owners sold their excrement to farmers. If there were fewer people living in an apartment, everyone’s rent went up because there would be less waste for the landlord to sell, he says.
But now, with half the planet living in crowded urban centres, “excrement is mostly seen as a threat,” he says. “You want to get it out, flush it away.”
That’s all fine, he says, until we start to consider both the necessary role of excrement in the planet’s ecosystem, and the sheer weight and numbers now involved.
As he wrote in one article:Each person on the planet (the average one, somewhere between starving children in the Sudan and obese adults in the US) puts out 150 grams of excrement per day. That’s about 55 kilograms in a year…
In 10,000 BCE there were about a million people on the planet. That’s 55 million kilograms of human excrement scattered around the globe in small piles, slowly feeding the grass and fruit trees. In 1800, there were about a billion people on the planet, so about 55 billion kilograms….
By 2013, with more than 7 billion people on Earth, the total human output was close to 400 million metric tons (400 billion kilograms) of shit per year. That is about eighty million large bull elephants’ weight of crap!
The main problem, he says, is that it’s only seen as a problem. If half the livestock manure in the world was used to produce energy, he says, it could replace about 10 percent of current fossil fuels and save billions of dollars.
“It’s trying to get people to rethink this whole thing of excrement not as a problem but as a way that materials are circulated. How can we do that in such a way that we minimise (health) risk and get all the value out, because that’s what sustains life on the planet.”
Waltner-Toews, who is Professor Emeritus at the School of Population Medicine at the University of Guelph in Ontario and founding president of Veterinarians without Borders, doesn’t expect an overnight revolution that will see all of us happily drinking sewage treated water or filling up our cars with dung diesel.
But he says there are opportunities for change, particularly in large agricultural operations where using manure to generate energy is a way to save money, not a cost as it would be initially in an urban setting.
As a critic of industrial scale agriculture, this causes him some discomfort but he pragmatically points to one example of a US dairy, which has 80,000 cows and uses their manure to run 40 or more trucks. “At that large scale, there is a good economic argument: they save on environmental regulation issues, they can run the trucks, they have energy for the farm. This is a way to use those nutrients: they’re not a problem, they’re a solution, they’re a resource in that system.”
But he also points to smaller examples that are both possible and start to change attitudes:
- city dog walking areas where dog owners have to scoop up their dog’s poop, put it into a biodegradable bag and feed it into a biodigester that runs the lighting for area
- Swedish trains that run on waste
- slum areas in Nairobi which generate hot and cold running showers
- prisons in Rwanda that are ‘powered by poo’.