Accessibility and Access Keys [0]
City Hall attracts all sorts of weird lobbies and interest groups. Maureen Reilly’s is weirder than most. As the director of the environmental group Sludge Watch, she has an intense interest in how Toronto disposes of the leftovers of its excreta.
For a dozen years now, Ms. Reilly has sat through committee meetings, pored over scientific reports, lobbied city councillors and more or less devoted her life to the burning question of what the city should do with the stuff technically known as sewage sludge (coy city officials call it biosolids).
When you flush the toilet, the waste water travels through the city’s 9,000-kilometre sewage pipe system to one of four treatment plants. There, it’s separated into water and solids. The water, cleaned and filtered, is discharged into Lake Ontario. The solids are sent to big tanks called digesters, where micro-organisms consume them as food. Even after all that, there remains a thick grey-brown liquid – 195,000 tonnes of it a year. Yes, ick.
The question of what to do with it has been concerning the city – and Ms. Reilly – for a long time. She has spent countless hours on the subject since moving on from jobs as an Ontario government policy worker, MPP’s assistant and owner of a country bed and breakfast. Since 2001, she has posted around 3,500 tidbits of sludge news and commentary on the Sludge Watch e-mail list.
She acknowledges that, as a cause, “it’s not exactly up there with save the whales,” but, all the same, sludge is a big challenge for a city of 2.6 million. Unless they start making us recycle it at home like everything else (make way for the brown box?), Toronto needs to find a sensible way to get rid of it.
At present, 41 per cent of sludge gets put into landfills along with the city garbage, but that solution is shaky. U.S. jurisdictions have sometimes balked at taking our sludge, and the city-owned Green Lane landfill has a limit on how much it will take. Another 11 per cent is treated and spread on farmers’ fields as fertilizer, but the neighbours often complain. (Ms. Reilly became an activist when authorities proposed dumping 5,000 tonnes of noisome paper-mill sludge on fields near her Kirkfield farmhouse east of Lake Simcoe.) A further 16 per cent is turned into dried pellets for fertilizer, but neighbours sometimes complain about that, too – especially when the pellets self-combust and catch fire. Five per cent is mixed with cement kiln dust, a process known as alkaline stabilization.
Yet another 23 per cent is burned in an aging incinerator at the Highland Creek treatment plant near Lawrence and Morningside. Incineration is always controversial. In the 2003 campaign for mayor, candidate John Tory proposed incinerating Toronto garbage. He was attacked from all sides. Incineration – Ms. Reilly calls it “the vilified I-word” – conjures up images of belching smoke and an almighty stink. Imagine the fuss that would come with building a new sludge incinerator. But Ms. Reilly says Toronto has to keep an open mind to new technologies that use heat to reduce sludge and produce energy as a byproduct.
It is a brave and unpopular stand. When the sludge issue came up at city council this month, Councillor Gordon Perks, an ardent environmentalist, said any kind of incineration, no matter how advanced, would put toxins such as furans and dioxins into the atmosphere. If the city were to propose a new incinerator, no matter where in Toronto or Ontario, residents would go crazy and then “the biosolids really hit the fan.” Ms. Reilly calls that nonsense. She says that cities from Vienna to St. Paul, Minn., use some form of sludge incineration without poisoning the air. Copenhagen’s Avedore wastewater plant extracts the water from its sludge then incinerates it, scrubbing and filtering the exhaust to strict European standards. The electricity generated in the process supplies half of the plant’s power.
Ms. Reilly gets a bitter chuckle out of the idea that Mayor David Miller visited the international climate-change conference in Denmark this month, “acting green as all get out,” and yet rejects a green-energy source that famously green Copenhagen embraces: sludge. “The mayor wants to move us into green environmental technology and the first thing he does is take a green solution off the table,” she says.
She is even more dismayed that city council took incineration off the table as an option for dealing with sludge when it recently discussed Toronto’s Biosolids Master Plan (yes, there is such a thing), a multiyear effort to evaluate sludge-disposal options. While she isn’t saying incineration is the only answer – her main gig is fighting the dumping of sludge on farmland – she says the city should keep its sludge options open.
Not only is incineration much cleaner and more efficient than it used to be, but new technologies offer a whole range of clean alternatives. A demonstration plant in Quebec is using something called plasma-assisted sludge oxidation. Sludge in a huge kiln is exposed to a beam of plasma gas, helping set off a thermal reaction that burns the stuff at high temperatures of 600 to 700 degrees Celsius and leaves very little residue.
Ms. Reilly finds it all “fascinating, absolutely fascinating.” After listening to her talk for an hour or so, it is hard to disagree. Like it or not, sludge matters.