A few years ago, Chris Olson had a big, green idea.
The former St. Albert resident was working for Edmonton's Construction Waste Disposal and noticed that the company was spending up to 40 per cent of its money on landfill fees.
He realized that he could shrink the volume of this waste by up to 80 per cent using a process called pyrolysis – the process that makes charcoal – and greatly reduce those fees.
"There was money to be made reducing waste," he says.
Olson teamed up with fellow Northern Alberta Institute of Technology student Bruce Saunders to test this theory with a fridge-sized pyrolysis unit last year.
The test was successful. Now, they've formed their own company to do something big.
"We've designed essentially a commercial scale slow pyrolysis system," Olson says: a 50-tonne lime green machine the size and shape of a shipping container. They've named it Ulysses after the James Joyce novel.
"It sounded good, I suppose!" Olson explains of the name.
The $1.6-million system will undergo a field test at the Edmonton Waste Management Centre later this fall. If it works, Olson and Saunders believe they'll have a system that can shrink landfills, generate electricity, improve crops, trap greenhouse gas emissions, and pave the way for future pyrolysis systems in Alberta.
"The technology has been proven," Olson says.
"We're building this system to prove it at a commercial scale."
Not just ash
The substance at the heart of this big green machine is char – a hard, black substance most people would recognize as charcoal.
Don Harfield has spent the last 10 years studying char out at the Alberta Innovates Technology Futures lab near Vegreville – a sprawling 640-acre site where multimillion-dollar machines stand side-to-side with pitchforks and tractors. He and his department are chipping in some $90,000 in technical support for the Ulysses project.
Char is one of the many technologies that can help build Alberta's economy and improve its environment, he says.
"We need to be making value-added products," he says, and char can turn our waste into valuable goods. His lab has been transforming everything from wood to barley to car seats into char to find out which trash transforms into the best treasure.
Carbon plus oxygen and heat causes combustion, Harfield says. Combustion lets the energy-rich carbon escape as CO2, leaving behind useless ash.
Carbon plus heat with little to no oxygen causes pyrolysis, he continues.
"You are cooking the biomass."
Heat waste to about 500 C and you pour enough energy into it to break up its molecules, explains Lloyd Helferty, an engineering technologist with Biochar Consulting in Ontario. If this happens in a low-to-no oxygen environment, the carbon atoms have to bond with each other to form solid char instead of floating off as CO2. The rest of the atoms in the waste create various by-products.
The Ulysses device uses a heavily insulated hearth to produce char.
You start by tossing any carbon-based waste into the hopper at the front, Saunders says. The waste goes through an airlock and is dropped onto a conveyor belt that pulls it through the hearth that's been preheated to 500 C with propane – picture a giant version of the oven they use at Quizno's restaurants.
The waste undergoes pyrolysis in the great heat and breaks into red-hot char and flammable by-products. The by-products are piped into a separate compartment above the hearth and ignited to create a roiling 1,100 C firestorm that destroys any pollutants. Exchangers shunt heat from this fire into the hearth to keep it at 500 C.
The finished char comes out of the machine by auger about an hour later. Saunders says. They have to quench it immediately so it doesn't catch fire.
Useful stuff
Olson says Ulysses should convert 50 to 60 tonnes of trash a day into five to 10 tonnes of char.
The uses of char depend on its quality, which differs based on its source. Saunders and Olson plan to run many different types of waste through Ulysses to see what kinds of char it can make.
One potential use is as a carbon sink. Research into ancient char-enhanced soils in the Amazon suggests that char and the carbon in it can last for about 2,000 years without decaying. This means we can use char to more or less permanently remove greenhouse gas emissions from circulation, Helferty says.
A 2010 study in Nature Communications found that biochar – char added to soil – could theoretically trap 1.8 gigatonnes of emissions per year in the ground on a sustainable basis – equivalent to 12 per cent of global emissions or the emissions produced by burning 75 billion cylinders of propane.
Char is very porous and has a huge amount of surface area for its size – a gram of it has the surface area of a tennis court, Saunders notes.
Add biochar to soil, and that porosity and surface area helps the soil hold onto water, nutrients, and beneficial microbes, and improves its carbon content, Harfield says – his team calls biochar "chicken soup for the soil" as a result.
Studies by Alberta Innovates have found that adding biochar to soil causes a significant increase in yield in oats after three years, reports researcher Dani Degenhardt. This could be useful to help make less fertile soils more productive.
Because it's so absorbent, char can also be used to remove pollutants from spills or contaminated soil, Degenhardt says. She envisions hurling a sack of the stuff into a tailings pond so that it can soak up contaminants like a reverse teabag.
Researchers have used char to make capacitors, lightweight bricks, feed additives, and paint, Helferty says – paint that improves air quality and blocks cellphone signals due to the strange electrical properties of char.
Olson and Saunders hope the char they make can be used as a form of activated carbon in filters. Even if it can't, it should still absorb pollutants if used to cover landfills, and could double the life of a landfill by shrinking waste volume.
"We can save up to a million dollars a year just in reduced tipping fees," Olson says.
They could also save money on heat and power. Olson says they plan to add a combined heat-and-power system to Ulysses that could create either 16 megawatts of heat or five MW of electricity – enough to power 4,000 homes.
Where's my char?
Char may have great potential, but right now, that's all it has: potential. The global char market is tiny, consisting of about 200 commercial producers and just 7,500 tonnes in sales per year, reports the International Biochar Initiative.
It's a chicken-and-egg scenario, as Degenhardt describes it: there's no market for char right now because it's not being mass-produced, and no-one wants to risk investing in production without a market.
Char also costs up to $800 a tonne to make due to all the labour and transportation of material involved, Harfield notes. That's way above the $100 a tonne farmers want to pay for it.
Forestry companies will have to start making char in order for it to catch on, he predicts. The waste wood they create could be turned through pyrolysis into valuable activated carbon.
"It is the value-added that's going to drive the costs of it."
Olson and Saunders will test Ulysses for several months to see how it performs. The information they get from the tests should help create regulations for pyrolysis in Alberta.
"Waste isn't really going anywhere," Olson notes, and no matter how much we reduce and recycle, we'll always have something that goes to the dump.
"That's where we kind of fit in."
