On the Air: Disposals vs. Trash

Is it better for Mama Earth to dispose of food waste by putting it down the sink disposal or into the trash? In the latest EcoMyths segment on WBEZ, Kate joins Jerome McDonnell to tackle the age-old question of whether it’s greener to send food waste down the sink and into our water system, or just to throw it in the landfill-bound trash can. Providing them with the answers are Eric Masanet, PhD, life cycle analysis expert at Northwestern University, and Debra Shore, commissioner of the Metropolitan Water Reclamation District of Chicago.

We asked Eric and Debra to shed light on that age-old mystery: Is it eco-friendly to put food waste down the disposal? Though they speak from different perspectives, both experts agree that generally speaking, wastewater treatment is more efficient than landfills. Moreover, the potential benefits they offer such as biogas and biosolids recovery make them hands-down the greener choice when compared with landfills. In Chicago, you can see this play out in the wastewater treatment plants that use a process called anaerobic digestion to convert methane to clean energy (rather than it being released as greenhouse gases into our already overtaxed atmosphere). You can also see the value in Maggie Daley Park, where some of the nutrient-rich biosolids from waste-water facilities are now enjoying a second life as soil fertilizer.

Still—though using a disposal to get rid of old food is generally greener than tossing it in the trash, it is NOT the best way to address our food waste issues. The single greenest thing we can do is to reduce food waste in the first place—an important task, considering that we waste about a third of food our food globally, according to several sources like this eye-opening NRDC report on food waste.

So what’s green, greener, and greenest in the world of food waste? It goes a little something like this:    All these options are generally greener than tossing food waste into a trashcan.

  • Not-so-green: Throwing it in the trash
  • Light green: Putting it down the disposal
  • Green: Using it as compost
  • Greenest: Eating it! (Or, just buying what you know you will eat.)

For more where that came from, including all the relevant science studies for anyone who’s up for a truly deep dive, read the myth.

-This content also appears at WBEZ.org. It is cross-posted here as part of our partnership with Chicago Public Media.