In response to Wednesday's story on the problems with coffee cups and K-cups, listener Richard Johnston from New York, sent in this question:

It's easy enough just to stop using the silly little one-shot plastic packets. Just as important is the question of what to do with the grounds. My late father, who had lots of plumber friends, said it was good to throw them down the drain because it helped keep it cleaned out naturally, but it seems like that might pollute something. Others say you should throw them in the garbage, which adds to the landfill. For someone not able to compost, what is the best solution?

You're right to be skeptical about putting coffee grounds down the drain. In New York City, the grounds you put down the sink are going to be sorted out in the waste water treatment process, and end up in landfills. (All you've ever wanted to know about New York's waste water system is here. See page 7-8 for coffee related information.) I've found a couple of government sources that say the grounds can be problematic--especially if you have a septic system.

So, pass.

Throwing your coffee grounds out in the garbage can also be a problem. You are adding to landfill volume and, when organics in landfills breakdown, they produce methane.

But it's not all bad news. Some landfills are now able to capture and repurpose the greenhouse gas. From Governing magazine: "Hundreds of landfills around the country have begun transforming methane into electricity and biofuels. The gas can be sent directly to buildings to run heating and cooling systems, can be purified into natural gas, and liquefied or compressed to power garbage trucks and city buses." There's an interesting article in Mother Jones about composting vs. methane capture.

If you've got a garden, or know someone who does--it could be the best answer for your spent coffee grounds. The grounds can be a soil additive, with some limitations. You don't want to use them on houseplants.

And, maybe it's time to reconsider that compost pile. There are ways to do it inside, even in city apartments.

Photo credit: Flickr user Steve Snodgrass.

Follow Adriene Hill at @adrienehill