We use cookies to improve your experience on our website. Accept | Find out more


Chop and Change

How last week’s pasta is on track to become the next big thing in environmental sustainability

Author Hillary Rosner Illustration Eva Vázquez


HIDING IN YOUR KITCHEN, disguised as the most mundane appliance imaginable, might be the next great tool for urban sustainability. We’re talking about your garbage disposal unit, the thing that sits beneath your sink and chomps your food scraps into oblivion. Maybe you use it daily and never give it a second thought. Or perhaps you’re an eco-conscious sort, and each time you flick the switch you wonder, “Is this thing bad for the environment?”

The answer to that question, it turns out, is no. In fact, as more cities try to cut their carbon footprints, slash their trash heaps and produce more energy, this humble domestic convenience could prove an intriguing ally. Here’s why: When you throw your food leftovers into the garbage can, they eventually end up in a landfill. There, as they decompose, they release methane, a greenhouse gas that contributes powerfully to global warming. Organic waste also takes up valuable space, costs money to process and lives up to its name—leaving this stuff to rot in a landfill wastes the chance to tap its energy.

Send your food scraps through your disposal and into the sewer system, though, and they’ll likely end up as biogas, a mix of mostly carbon dioxide and methane produced by microbes as they digest the organic material. Unlike most landfills, many wastewater treatment plants actually use the methane they generate. Sewage treatment is an energy-intensive business; by encouraging microbes to gobble up your waste inside special tanks, these facilities are able to capture the gas to power their operations. In the past, when sewage plants made more methane than they needed, they simply flared it off. But now they’re looking for ways to expand usage of the biogas, like delivering it into natural gas pipelines or the electricity grid.

This makes your banana peels and last week’s pasta a potential source of locally made energy, like your own tiny barrel of oil. Or perhaps an entire oil well: The average family of four generates 17 pounds of food waste every week. Nationally, food scraps make up roughly 14 percent of food waste, most of which ends up as landfill trash, according to the Environmental Protection Agency.

Having caught on to the value of organic waste, a number of cities are looking for ways to increase the amount that flows to their sewage plants. Across the U.S., nearly 850 wastewater treatment plants use biogas as a source of energy. Some municipalities are even tapping local businesses’ byproducts, using everything from brewery hops to over-the-hill supermarket produce in order to ramp up biogas production. In fact, the race to make biogas is altering the image of the sewage treatment industry, which is rebranding itself from “wastewater management” to “water resource recovery.”

If you happen to be a company that manufactures garbage disposals, meanwhile, all of this amounts to an interesting business opportunity. “Disposers can effectively divert food waste away from landfills and turn it into both an economically and an environmentally productive resource,” says David MacNair, vice president of global marketing and strategic development for the InSinkErator unit of Emerson Electric. InSinkErators are the most popular brand of disposals, and the company aims to grow its business by helping cities go green.

“Disposers have been sold as a consumer convenience and a hygiene appliance—it’s all about the environment in your kitchen,” says MacNair. “This conversation we’re having today isn’t about the environment in your kitchen but in your neighborhood and in the world.”

Last year InSinkErator launched a pilot project in Philadelphia, where food waste makes up roughly 20 percent of the trash delivered to landfills. In the city’s two wastewater treatment plants, food scraps are converted into clean water, biogas and fertilizer. As part of the city’s Greenworks sustainability program, InSinkErator installed nearly 200 units in homes in two neighborhoods. The project will measure the amount of food waste diverted from landfills. This spring, similar projects rolled out in Tacoma, Milwaukee and Chicago.

The biogas movement is spreading slowly, and it may still be a while before Americans feel empowered and proactive every time they dump leftover soup into the disposal. But as far as appliances go, there’s nothing in your kitchen with quite as much revolutionary potential.
For InSinkErator, the challenge now is how to turn those green chops into a selling point. Unlike, say, an electric car in the driveway or a rack of solar panels on the roof, an InSinkErator “is hidden under my sink,” says MacNair. “I get zero credit for having it.” Just a warm, fuzzy feeling and an empty trash can.

Colorado-based writer HILLARY ROSNER is working on upping her pasta intake in order to save the planet.

One Response to “Chop and Change”

  1. stephen Says:
    May 5th, 2014 at 3:20 pm

    what if your waste water treatment plant does not capture the biogas. And what about other sludge material. Is this being used as compost? What percentage of waste water treatment plants out there are actually capturing the biogas? And how can I tell which is my water water treatment plant and how can Itell if they are capturing biogas?

Leave your comments