Let’s Tap the Energy in Household Trash, Farm Waste
Corn-based ethanol might not be such a great idea (bad for the environment and a waste of food), but what about waste-based ethanol? It’s hard to see a downside to making fuel from stuff we’d be throwing out anyway (and that, if left to decompose naturally, would probably generate lots of greenhouse gases).
That’s what U.S. Agricultural Research Service scientists in Albany, California, are investigating right now: how to take household garbage and agricultural waste and process it so the end product is clean and renewable ethanol.
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“MSW (municipal solid waste) is produced year round and is already collected and transported near population centers,” says chemist Kevin Holtman. “That means the biorefinery won’t be based on the tight economics associated with traditional crop-to-ethanol operations.”
Holtman and his colleagues say municipal waste would have to be treated first in a kind-of oversized pressure cooker to yield a clumpy material that could be fed into a biofermenter. The farm leftovers — rice straw, lettuce leaves, almond hulls, etc. — would also need some kind of pretreatment before they’d be ready for biofermentation.
The challenge right now it how to treat those materials in the most eco-friendly way, using just water and heat rather than harmful chemicals. If researchers can find the right solution, though, the rest will be relatively simple: just add enzymes and yeast to the mix and let them do their work, with the end product being ethanol.
Besides providing a clean and renewable energy source, the waste-to-ethanol strategy could also reduce the amount of trash going to today’s landfills.
“It’s an alternative for the here and now — not something that’s 10 years down the road,” says Bill Ort, leader of the research unit.
You can find more details about the trash-to-fuel research here and here.
