Separating the waste from the chaff

Garret Gillespie hopes that no one ever has to use his invention. He's the type of guy who is more proud of his history as a farmer than his master's degree in engineering.

Garret Gillespie hopes that no one ever has to use his invention.

He’s the type of guy who is more proud of his history as a farmer than his master’s degree in engineering.

And he doesn’t believe that technology can help with anything in the long run.

Take composting, for example.

Everyone should be doing their own composting rather than just throwing it into those fancy new green bins.

If everyone did their own composting, they might realize certain things just don’t break down – like rubber bands, fruit stickers and plastic bags.

Even those so-called biodegradable plastic bags – the special ones people fork over heaps of money for – aren’t good for compost.

“To be biodegradable, they need a lot of UV light,” said Gillespie. “It’s just conventional plastic with an additive added to it. They take a minimum of three years to actually break down. It’s a great big scam is what it is.”

It’s also a great big problem for Whitehorse’s compost program.

During the natural composting process, the waste is maintained at 70 C for six weeks. That’s enough to break just about anything down, even motor oils and pesticides like DDTs.

“But those damn plastic bags … they’re tenacious,” said Gillespie. “After all that, we once pulled one out and that was still in mint condition.”

Gillespie’s invention will take on this plastic problem.

He’s created a large Dr. Seussian machine, called the Plastovac Plastic Separation System.

It is now being used in Victoria to great success, and Gillespie’s got a deal with a large multinational company to continue to improve upon the design.

Last week, he was touting the benefits of his Plastovac at the Yukon College’s Research Innovation and Commercialization Workshop.

As a farmer, Gillespie’s been into composting all his life.

“It’s pretty straightforward when you’re dealing with manure,” he said. “But dealing with food waste is much more challenging.”

Originally from Ireland, Gillespie had an organic farm in the Yukon for nearly a decade. He quit farming in 2009 because it was becoming more and more difficult to make a living.

Having a little extra time on his hands, Gillespie decided one day to check out Whitehorse’s composting facility. He was shocked by what he found.

“It was about 10 per cent plastic and largely the biodegradable plastic,” he said. “I was gobsmacked.”

The problem with plastic is that it interferes with the composting process.

Gillespie likens it to trying to breathe with a plastic bag over your head – the microbes involved in the composting process have trouble getting the air and water they need to thrive.

It also adds to processing costs and wears out the machinery.

The intent of any good industrial composting program is to sell the finished product at the end. But nobody wants to buy a bag of compost for their garden that’s filled with plastic.

There are machines on the market that can help get rid of the plastic from compost, but they cost anywhere between $250,000 and $500,000.

Instead, Gillespie built a device for the city, using salvaged parts and a little farmers’ know-how.

It only cost $14,000, and it worked like a charm.

He decided to give his contraption a funny name, the Plastovac, inspired by Dr. Seuss and Wallace & Gromit.

“The problem is so insane, it could get very depressing very quickly,” he said. “I choose to laugh at it instead.”

With Gillespie’s help, the city was able to start selling its compost in the summer of 2010.

Gillespie was proud to say the compost they created met all guidelines and even passed Canadian Organic Standards.

But even at a discount price of $5 for an 11-kilogram bag, not much ended up selling.

“It’s not the fault of the compost or the city,” said Gillespie. “It’s just that there’s a poor public perception of municipal compost. No one wants to buy compost for their garden from the landfill gatehouse.”

After Gillespie left his contract with the city, he received funding from the Yukon Technology Innovation Centre to continue working on his Plastovac idea.

He went back to the drawing board and came up with a more heavy-duty model.

A consultant whom Gillespie works with down in Vancouver expressed interest in this latest reincarnation of the Plastovac. He took the machine down to an industrial compost operation in Victoria and asked them to throw the worst stuff they had at it.

The design isn’t flawless, and even in the best cases, the Plastovac is unable to remove all the plastic from a pile of compost. But the machine works far better than its more expensive European counterparts.

Gillespie’s invention has attracted the attention of Vermeer, a multinational corporation that specializes in agricultural, environmental and construction equipment. He now has a deal with this company to cook up a superior prototype.

“All the work to date has been in the field, farm-style, practical know-how stuff,” he said. “What’s missing is the applied engineering research.”

Gillespie isn’t exactly donning the white lab coat – that’s not likely to ever happen.

But he is doing a literature review right now. And in the next few months, he’ll start doing some applied experiments at his shop in the Marwell industrial area.

He wants his next prototype to be able to get down to even the smallest bits of unbiodegradable junk that finds its way into compost.

Gillespie won’t go into too many details about how the machine works.

It uses air classification, which he compares to the ancient art of winnowing grain. Gillespie also came up with a supplementary separation system, which also draws on ancient knowledge – this time a technique used for seed cleaning.

He’s unclear whether or not the new prototype will be used in Whitehorse and again be sent down south.

“I hope I don’t have to leave the Yukon to test this technology,” he said.

“My deep desire is to work with the city, so that we can all benefit and continue to improve.”

But the new machine will probably never be able to remove all the plastic. The only way to do that would be for everyone to stop using those so-called biodegradable plastic bags, and take more care with what they throw in the green bin.

“It’s a transitional technology, to help us get to a saner place,” he said. “Something that will help us get to a place that we’d be proud to leave to our children.”

Contact Chris Oke at

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