Turning greasy, gooey food waste into energy

Integrated operations like Harvest Power are pointing the way to a zero waste future

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By David Dodge
and Duncan Kinney
The Green Revolution

RICHMOND, BC, Apr 5, 2014/ Troy Media/ – Picture one meal in your day and imagine it getting tossed into the trash before you even got a chance to bite into it.

Every single day we either lose or waste one third of our food. that’s 1.3 billion tonnes a year. Not only could we have fed people with that food but it’s an astonishing waste of energy as well. Just think of all the energy that goes into growing, fertilizing, processing and transporting 1.3 billion tonnes of food a year.

To let the gravity of this wastage sink in head to this infographic and mouse around it for a while. Go ahead, we’ll give you a minute.

Harvest Power has a partial solution. We visited its site in Richmond, B.C., one of 38 similar operations across North America that turn your rotten bananas and wilted lettuce into energy and compost.

Harvest works with 13 municipalities and numerous commercial food waste haulers in the Lower Mainland to handle their organic food and yard waste. And the amounts are big: it handles over 200,000 tonnes of waste a year. Of that, 40,000 tonnes is diverted to what they call the energy garden. It sounds nice and pretty and bucolic, but to see a truck dumping gooey, mushy organic waste doesn’t exactly make me think of any garden I’ve ever been to.

Trucks back up, dump the food waste onto the tipping floor where it’s mixed with yard waste, shredded and then pushed into long, rectangular chambers with airtight doors. When those doors are sealed the organic materials are biochemically degraded into organic acids. The solid materials go back into the compost stream and the organic liquids go into the digester where anaerobic bacteria release methane that is used to fuel a one megawatt cogeneration power plant.

Turning all of that food waste into energy is a good idea, but the anaerobic digestion process leaves you with a hot mess called digestate. Harvest Power closes the loop by composting the scentless but not very appetizing looking digestate.

When you visit the Harvest Power site it looks like acres and acres of compost covered by thousands of gulls with a few dozen bald eagles sprinkled in to liven things up.

Composting is a pretty simple process – mix food waste with woody or leafy yard waste, make sure there’s enough water (not a problem in rainy B.C.) and move it around enough to make sure oxygen can get in. Obviously, managing a composting operation that handles 200,000 tonnes a year is a complex operation, but food waste, yard waste, water and air are the four basic ingredients.

“We’re doing 100 or more than 100 trucks per day, covering 30 or 40 acres. So the challenge is managing to the scale of a centimetre on the operation that’s very large, and really what that means getting one’s hands dirty. So knowing what’s happening on the site by a handful-by-handful basis. So it’s just diligent management and attention to detail,” says Geoff Hill, the manager of the compost operation. Hill knows the subject well: he has a PhD in composting.

The aerobic, or oxygen loving composting operation is just as important as the anaerobic, or oxygen-starved digestion process, as it keeps the smell down and creates an important new revenue stream for Harvest Power. The composting operation completes the life cycle of food and actually imitates nature. No other species out there has garbage dumps or landfills and Harvest Power treats food waste as just another nutrient circulating in a healthy ecosystem.

When you actually break down how Harvest Power makes its money the energy generation side of things is just icing on the cake.

The tipping fees are the biggest moneymaker as they charge roughly $50 a tonne for truck after truck to drop off their waste. The second most important source of revenue is the sale of the compost, which sells for $20 a cubic yard. And third is the money generated by their one-megawatt plant producing and selling electricity to the grid.

Turning our food waste into energy and compost appears to be a way to virtually eliminate the flow of food and organic waste to landfills. And without coincidence the City of Vancouver is set to ban organic waste from landfills by 2015.

It already costs less than a landfill to dispose of organic waste at Harvest Power. While it’s still a good idea for North Americans to reduce their organic and food waste, integrated operations like Harvest Power are pointing the way to a zero waste future.

Troy Media columnists David Dodge is host and Duncan Kinney editor and production manager of Green Energy Futures, a multi-media series presented at www.greenenergyfutures.ca. The series is supported by Suncor Energy, TD, Shell Canada and the Pembina Institute.

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4 Responses to "Turning greasy, gooey food waste into energy"

  1. Troy Media
    Troy Media   April 5, 2014 at 12:13 pm

    Letter to the editor:
    We should have operations like this set up in
    every major municipality across Canada. Generating compost for soil
    enrichment and containing the methane to be used for generating
    electricity. Win, win, win.
    It is almost hard to believe that we call these resources WASTE, and
    then bury them, with resulting increases in greenhouse gas
    concentrations in the atmosphere.
    Eventually, perhaps we could use better industrial uses for the methane
    than to be combusted for electricity, generating CO2.
    Preston Walberg

  2. Troy Media
    Troy Media   April 5, 2014 at 9:56 pm

    Letter to the Editor:

    Hmm. In the US, it
    used to be necessary to separate food waste from other trash. It required
    dealing with two different hauling companies. When Los Angeles banned burning
    of paper, its residents had to deal with a third company to haul that off.
    Then in 1960 or so Sam Yorty became mayor of Los Angeles at least in by
    promising that housewives would be able to commingle all three kinds of trash
    and deal with only one hauler. Very convenient. The idea went nationwide
    It set up the daft chemistry experiment that became the “sanitary”
    landfill. It made it more difficult than it should have been to get people in
    the habit of recycling. And as far as I can see makes large-scale composting
    of food waste (or anything else organic) unreasonably difficult.
    So do Canadians still have to separate food waste from cans, bottles, and the
    like? Ah you backward people who never partook of the “progress”
    south of your border.

    By David Guion

  3. Troy Media
    Troy Media   April 6, 2014 at 9:19 am

    Letter to the Editor:
    In my house we feed
    food waste to the wild birds. Or make compost.
    Of course food waste should be separated or it contaminates the paper and
    makes it unusable.

    By Clare O’Beara

  4. Avatar
    greenergy_dave   April 7, 2014 at 10:34 am

    If there is a theme we have encountered in our Green Energy Futures series it’s using waste as a resource. In Edmonton the system is even simpler – recyclables go in one bag and trash in another. The entire garbage stream is essentially a giant composting operation. This is very easy for residents to participate and quite efficient as a system. The addition of a biofuels component is bringing their waste diversion to 90%. The side benefit of recycling for a few decades is that residents of Edmonton are also very good at setting toxics aside (paint, batteries, CFLs etc) and taking them periodically to ecostations in the city.
    We have found innovative waste to energy (and compost) systems across Canada and the scale is way past demonstration leading us closer and closer to the possibility of zero waste.

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