Big Trouble with Little Garbage Disposals?

Let’s take a timeout from our normal topics to address a rather unusual, but completely valid, environmental concern — garbage disposals. I came across an article in Slate yesterday, where a troubled reader wrote in with this question:

I’m sorry to say I live in an apartment without a composter for organic waste. Given the circumstances, am I better off feeding my leftover mashed potatoes into the garbage disposal, so they don’t end up in a landfill? Or should I throw them in the trash can, so they don’t end up the water supply?

A very good question, and certainly one that warrants some time and discussion! Though it doesn’t seem to weigh heavily on many peoples’ minds here in the United States, apparently other countries are already starting to tackle it, on the basis that the benefits versus costs of garbage disposals are ambiguous, to say the least. On the one side, water treatment plants are made to handle what your dirty dishes dish out:

It is true that with the major exception of grease and fats—which can block pipes and cause overflows—water-treatment systems are designed pretty well to handle most of the scraps you might have left over from dinner. The leftovers you shovel into the sink will eventually make their way to a wastewater plant, where the sewage goes through “grit treatment,” which strains out the largest solid matter. (Sewage treatment is one of the few disciplines in which you can use words like grit, sludge, and scum as technical terms.) Whatever stuff gets separated from the water is either landfilled, condensed into fertilizer, or digested by microorganisms.

On the other hand, every instance of waste inevitably has consequences:

Still, dumping waste into the water system has environmental costs. There is evidence that the effluent that is pumped back into local water streams does affect their chemical composition and aquatic life. In extreme cases, the result can be something called eutrophication, which occurs when a higher concentration of nutrients results in algae blooms. According to one Australian study, the eutrophic impact of sending your food waste down the disposal is more than three times larger than sending it to the landfill. You’ll also be using a lot more water if you decide to go with the disposal—and you’ll be indirectly responsible for the extraction of the metal needed to make the appliance.

The article does note that studies on both sides of the debate tend to be rather biased toward whatever program or company funded the study. Then, there’s the question of landfill transport versus water consumption, and every other variable. Basically, it all comes down to your individual circumstances. How is the drought situation in your area? If water is running low, you may want to avoid, well, running it whenever possible (and trashing your food scraps rather than sending then down the drain). Check into your town’s water treatment program and effectiveness, and make sure you can be trusted not to accidentally stuff bacon grease and chicken bones down your kitchen pipes.

And remember: if you have the means to compost, it’s better than any of the above.

Photo via Flickr!

Wednesday, October 1st, 2008 at 10:14 am and is filed under The Daily. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.