You now have to compost food scraps and yard cuttings if you live in California

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How will waste haulers adapt to handling a lot more leftovers? California has set a goal to reduce the amount of food scraps and yard waste that go to landfills by 75%. The deadline is 2025. Raquel Maria Dillon from member station KQED visited a composting facility to take a look.

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RAQUEL MARIA DILLON, BYLINE: At a sprawling commercial compost facility in California's Central Valley, an 18-wheeler backs up onto a ramp to dump a load of waste into a huge hopper.

ROBERT REED: There's a lot of coffee grounds and eggshells and banana peels and things of that nature in there.

DILLON: Robert Reed is a spokesperson for Recology, the company that hauls away San Francisco's waste. This facility in Tracy, Calif., is where food scraps and yard clippings get turned into something useful.

REED: So all of those materials are natural materials. They all came from the Earth, particularly the food scraps - very rich in nutrients.

DILLON: Reed is hyped about composting because it keeps greenhouse gases out of the atmosphere.

REED: This is what makes the world go round. This is what helps grow healthy plants. So we've got food to eat, and it gets carbon back into the soil where it belongs.

DILLON: Then he plunges his hands into a steaming pile of compost.

REED: Oh, it's so hot in my hands.

DILLON: At this stage, the compost has been sorted and dried to a fine dust. It's now a rich brown color and smells sweet like a wet forest floor. Sprinklers add water, and pipes pump air to make a perfect spa-like environment. These piles are where bacteria do their work.

REED: There are eight or 10 feet tall, and they're just chock full of microbial colonies that are breaking the material down into smaller and smaller pieces.

DILLON: When food waste decomposes under these carefully controlled conditions, bacteria produce less methane than they would in a landfill. Methane is a greenhouse gas that lasts longer in the atmosphere and contributes more to climate change. Reducing methane emissions is the main goal of the state's new composting regulations.

MATTHEW COTTON: To go after food waste that aggressively is kind of unprecedented, and it's a big deal. But we have a lot of infrastructure - maybe not enough.

DILLON: Matthew Cotton is a commercial composting consultant. He says building enough large-scale composting facilities will be expensive, requiring land, heavy machinery and technology. But it'll be offset by $90 million from this year's state budget to help make it happen.

COTTON: It's not a popular piece of infrastructure. No one says, hey; let's put in a composting site. You know, it serves a lot of people, but nobody really wants to live by it.

DILLON: The other big hurdle is getting people to sort their food waste correctly. If they don't, the final compost product will be contaminated and less desirable to farmers and landscapers. Think plastic bags, rocks, those annoying little stickers on fruits and veggies.

SALLY BROWN: Is the top lid of your Haagen-Dazs container - it feels like cardboard. Is that plastic on the edge?

DILLON: Sally Brown, a soil scientist at the University of Washington, says composting can be tricky when you've been throwing stuff away the same way your whole life.

BROWN: Do you really care that much, or do you just care so much that you're going to put it in because it should be compostable?

DILLON: Brown says California is in a golden age of compost research and policy. Scientists are trying to measure how much carbon compost locks into the soil and how that benefits the climate.

BROWN: And it doesn't require genius cold fusion technology. It requires you to put your broccoli stems in a different bucket. You know, we can handle that.

DILLON: Brown says composting may be one of the easiest ways individuals can fight climate change.

For NPR News, I'm Raquel Maria Dillon in Tracy, Calif.

(SOUNDBITE OF JOEY FEHRENBACH'S "INDIGO ROAD") Transcript provided by NPR, Copyright NPR.