Albany, NY, is one of a growing number of cities burning sewage leftovers for energy. Could Toronto follow suit?
Public Works looks at public space, urban design, and city-building innovations from around the world, and considers what Toronto might learn from them.
We really are full of crap. And that’s a good thing. Because the matter you so effortlessly flush down the tubes each day can be an excellent source of renewable energy.
Since March 2013, North Wastewater Treatment Plant near Albany, New York, has been burning the sludge leftover from sewage treatment.
See, everything we city-dwellers flush down the toilet and wash down the sink or shower ends up at wastewater treatment plants. There, solid waste is filtered out of this foul tide, before the water is disinfected and sent out into nature.
In Albany, the remaining solid waste, called biosolids, are dried, then burned, and the resulting gas is used to generate power.
The plant estimates it generates about 75 per cent of the energy it uses, saving taxpayers about $400,000 per year.
And Albany is not the only city interested in this. Chicago’s sewage treatment agency has pledged to produce all its own energy by 2023, using the same process.
And we’ve gotten as far as burning biosolids in Toronto, but not as far as recovering energy from it.
Each year Toronto’s wastewater system produces about 195,000 tonnes of biosolids which is dealt with by the Ashbridges Bay plant and the Highland Creek plant in Scarborough. And incineration and energy production are already part of Toronto’s biosolids plan.
Highland Creek burns all the biosolids it handles–around 20 per cent of the city’s total biosolids. But according to Frank Quarisa, director of Wastewater Treatment for the City of Toronto, the incinerator system at Highland Creek dates from the 1970s, and predates energy recovery technology.
Not that we don’t put some of our biosolids to good use. Half of our biosolids are “land applied,” meaning they are spread around crop fields, forests, tree nurseries and areas degraded by mining, where the waste puts nutrients back into the soil, not unlike putting manure fertilizer on your garden.
But as of 2010, more than a quarter of Toronto’s biosolids get diverted to landfills. The City says covering landfills with biosolids discourage rats and other pests from getting in there, and prevent water from seeping into the garbage. But the City also acknowledges that landfilling squanders the nutrient and fuel value of biosolids and says it is committed to reducing the amount of solid waste sent to the dump.
Plus, as North Wastewater executive director Richard Lyons told Politico back in 2013, the idea of gaseous by-products being turned into energy can be replicated by other industries.
So there you go. From flushing to flaming to feeding fuelling. Our waste can do it all.
We just need to take the plunge.