Fresh Sheets

A portfolio of writing by Tamara Neely.

Sorting Calgary’s recyclable goods March 26, 2011

Filed under: Environment,lifestyle — Tamara Neely @ 05:04

It was a bizarre switch in 2009 to start throwing all of our recycling together in one bin.

Recyclable materials are dumped on the sorting floor of the City of Calgary's material recycling facility (MRF).

After all, many of us once believed that in order for the City of Calgary to recycle, materials had to be separated into plastics, paper, metal and glass.

And after all of this packaging is trucked to the material recovery facility (MRF), the trip a yogurt container takes from your home sink to being made into a lawn chair is actually a fascinating one.

The motivation to recycle comes from the city’s goal to drastically reduce the amount of waste heading to landfills to 20 per cent by 2020. In 2003, when that goal was presented to council, 80 per cent of the waste generated across the city was going to landfill. And a recent study has revealed that last year, waste going to landfill was down to 61 per cent.

To reach the 20 per cent goal by 2020, businesses, schools and construction developments will have to change some of their ways. That group accounts for two-thirds of waste generated in Calgary, and there are no statistics on how much they’re currently recycling.

As the city staff and council contemplate how to divert more garbage from Calgary’s dumps, robotics plug away to prepare our recyclable goods for global markets.


A 30-square-metre building in southeast Calgary, the MRF has a massive system of conveyor belts with spinning discs, air jets, magnets and robotic cameras. Staff at either end of the conveyor system are responsible for quality control, but otherwise the recycling goods are separated by a miraculous feat of physics, engineering and computer programming.

Once the piles of materials on the conveyor belt pass a human checkpoint, robotics take over by distinguishing the physical properties of paper, glass, plastic and metal.

A series of rotating discs allows paper to float over top and carry on, while containers and cans and other such objects fall through open spaces.

Several cameras along the conveyor belt register items passing underneath and trigger air jets to blow the different objects down their respective off-chutes.

These optical sorters are so smart that not only do they recognize the difference between a soup can and a toilet paper roll, but they also classify different types of plastics, from type one through to seven.

Next along the line, a large magnet pulls metal food cans out of the system — except for aluminum cans, which are immune to magnets.

The geniuses behind the robotic system worked with the physical properties of non-ferrous metals such as aluminum to create a different method of separating them. Legg says they use computer-driven equipment to change the magnetic field and create what’s called an “eddy current,” which punts aluminum cans off of the conveyor belt and down their own chute.

At the end of the line, staff find very little that is in the wrong place.

“It works really well,” said Legg. “It’s a neat process, I must say.”

In 2008, the year before the city launched its curbside pickup program for recycled goods, some 41,000 tons of recycled goods was sold to market. Last year, that number had increased to 70,000 tons.

And, for the most part, Calgarians understand which materials can be recycled. “Eight to 10 per cent of the stuff that comes into the MRF are unacceptable items,” says Parnell Legg, a waste diversion specialist for the city. “It’s stuff like household hazardous waste, scrap metal like frying pans and wire hangers.”


Dave Griffiths, Calgary’s director of waste and recycling services, says the large chunk of organic waste has prompted the city to consider a pilot composting pickup program next year.

The city is also turning its attention to the 158,000 apartments, townhouses and condominiums — 35 per cent of all homes — that don’t receive recycling pickup service from the city.

Also on the city’s radar are the two biggest garbage-makers: of the 650,000 tons of waste produced in 2010, one-third came from the industrial, commercial and institutional sector and another one-third came from the construction and demolition sector. The city recently started a recycling pilot program to divert asphalt shingles, drywall and non-treated wood from the dump.

“When you build an average North American home — and this is true in Calgary — that will generate five tons of waste,” says Griffiths. “When people move in, they won’t contribute that much waste for six years.”

Although Calgary is introducing new recycling programs, it certainly has a lot of catching up to do with other Canadian cities. Edmonton, for example, boasts a current diversion rate of 60 per cent with the goal of reaching 90 per cent by the time Calgary assesses its composting pilot program.


Published March 17, 2011 in Fast Forward Weekly.


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