Spring Themes: Composting
[you can skip my musings and go straight to Alex’s compostable plastics story!]
Today’s forecasted high temperature where I live in the Northeast is 78 degrees. That just doesn’t seem right. This time last year, we still had an impressive layer of snow which didn’t melt until sometime in April. [insert random thoughts of global warming, La Nina, and how yesterday was almost 20 degrees warmer than the forecast promised]
Over the weekend I took the opportunity to turn my compost pile. It’s got mostly kitchen scraps, a few bits of brown paper bag (worms love ’em) and leaf litter. Home composting is both an art and a science – my pile had too much nitrogen and not enough carbon, so I added more dried leaves.
I also noticed a plastic spoon in the pile, normally a no-no. But this one was made of PLA, a plastic derived from corn that is supposed to be biodegradable. It still looked pretty new, though, mostly because my backyard pile cannot reach the high temperature and rabid microbial activity of an industrial scale composting operation.
If I lived in San Francisco (and today it feels like I do!) I would put the spoon and my kitchen scraps, and perhaps some lawn wastes into a compostable plastic bag and set it out to be picked up. This week’s issue of C&EN features an in-depth, fascinating story by Alex Tullo on how compostable plastic trash bags – plus disposable dinner ware – can enable cities to divert 50% or more of trash away from landfills.
From the story:
In a landfill, food scraps generate methane, a much more potent greenhouse gas than CO2. They also form acids that leech out of landfills. “If you ask all these cities what the largest component of their waste going to the landfill is, it’s food,” he says. “And what is one of the worst things to go to the landfill? It’s food. The only thing worse is hazardous waste.”
Now think about your household’s waste. To reach San Fran’s goal of diverting 100% of municipal trash from landfills, it would have to be either recycled or composted. Plastics can be recycled, but if they get into the composting supply (like a random fork, or the trash bag holding the food waste) then you’ve already broken your system.