Ok, Where Does Garbage Disposal Waste *Really* Go?

Ok, Where Does Garbage Disposal Waste *Really* Go?

This is part of our ongoing series, called DTL (that stands for Down to Learn), where we take deep dives into the odd, nuanced and mysterious world of sustainability. Each article in our series should give you a good icebreaker for your next Zoom, or perhaps even inspire you. This piece was penned by contributor Jacqueline Parisi. 


Is it just us, or does it seem like garbage disposals are in every single kitchen these days? Now don’t get us wrong, we get the hype (they’re sleek! convenient! easy to use!). But we also can’t help but wonder how eco-friendly they *actually* are. Where does the food go once it’s pulverized? And how does the nifty contraption, which was invented back in 1927, stack up to the compost bin? 

Continue reading for the full low-down.

How do garbage disposals work? 

Garbage disposals live underneath the sink. Solid food scraps collect in a chamber, which is outfitted with an impeller plate in order to grind everything up. The food is then transported (with water’s help) through holes in the chamber wall. 

Where does the food go?  

Once the food is dissolved, it’s transported to a wastewater treatment plant. Any solid food scraps that remain are filtered and sent off to either a landfill, incinerator, or anaerobic digestion facility for energy conversion. 

And the million-dollar question...is the process sustainable? 

Not as much as you’d think. Here’s why: 

  1. Food scraps in a landfill is a big no-no

Because long story short, when organic material gets buried under heaps of other trash, it isn’t exposed to much (or any) oxygen while decaying. This causes it to release methane—a potent, no-so-green greenhouse gas that is second only to carbon dioxide in its implications for climate change. 

  1. It takes a whole lot of water to propel food waste down a pipe 

This energy and water-intensive process is less than ideal, especially in areas suffering from shortages. 

  1. It’s potentially harmful if the landfill is located near a body of water 

It goes without saying that landfills which risk harming marine and plant life. 

But...and here comes some good news...how sustainable your garbage disposal is ultimately depends on the processes your neighborhood has in place, as certain big cities are ditching the landfill in favor of converting food waste into energy, which is far more eco-friendly.  

Tips for responsible disposal

  1. Call your local water treatment plant to get the deets

Here are some important questions to ask: 

  • Do you accept organic waste? 
  • What do you do with solids? 
  • Do you have a methane capture system at your water treatment plant?

  1. Take a cue from the EPA’s “Food Recovery Hierarchy” pyramid

In the order of most preferred to least preferred, here’s what they recommend: 

  • Reduce the volume of surplus food generated  
  • Donate extra food to food banks, soup kitchens, and shelters 
  • Divert food scraps to animal food 
  • Provide waste oils for rendering/fuel conversion, and food scraps for digestion to recover energy 
  • Compost to create a nutrient-rich soil amendment 
  • Landfill/incineration  

  1. If you’re going to use a garbage disposal, make sure to avoid foods that could cause clogs
Including fibrous veggies like celery and edamame pods, corn husks, clam or oyster shells, eggshells, and fats/oils/grease (which will eventually congeal downstream). And yes, foods like peanut butter and dairy products (heavy cream, butter, ice cream) also fall into this category. The more you know! 

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