HARI SREENIVASAN: Now a story about trash.

As the nation produces more and more, one city is trying to eliminate all of it.

NewsHour correspondent Spencer Michels reports.

SPENCER MICHELS: Each year, Americans throw away about 250 million tons of garbage. That's roughly four pounds per person per day.

You can find all manner of trash in a landfill, old bent music stands, plastic bags, and a lot of items that could have been recycled, like bottles and cardboard. Beyond the obvious blight they cause, landfills create environmental damage and emit harmful greenhouse gases. They are monuments to waste.

Those concerns have prompted San Francisco and a handful of other cities to aim for a once-unthinkable goal, zero waste.

In 2009, San Francisco became the first city in the country to require that residents and businesses alike separate from their trash compostable items, like food scraps, and recyclable goods, like paper, metals, and plastic, into separate bins.

And that has led to a big reduction in the amount of garbage headed to the landfill, according to San Francisco Mayor Ed Lee.

MAYOR ED LEE, San Francisco: We're proud of the 80 percent diversion rate, the highest in the country, certainly of any city in North America.

SPENCER MICHELS: Lee likes to talk garbage. He touts the fact that the city's recycling and composting law has helped the city keep 80 percent of its waste out of landfills. The national recycling average is just 35 percent. But Lee wants the city to go even further.

ED LEE: All of us, as part of our culture of living here in the Bay Area, have appreciated the goals of our environment and climate change and doing everything that we can.

And I think the 80 percent, we're not going to be satisfied with that, Spencer. We want 100 percent zero waste. This is where we're going.

SPENCER MICHELS: Is that possible?

ED LEE: I think it is. It is possible.

SPENCER MICHELS: What do you do with a plastic bag? You can't recycle that.

ED LEE: Well, we have banned plastic bags in the city.

San Francisco residents Sven Eberlein and Debra Baida think it's possible, too. They are avid recyclers and composters, so much so that they produce almost no trash. Baida lists what goes into the compost bin.

DEBRA BAIDA, San Francisco resident: We put the wrappers from our butter. We put any meat or packaged -- that kind of packaged paper food, soiled food wrappings like that, tissues, Q-tips, paper napkins, which we don't have in our home. If those come in, those go there. Soiled paper plates, milk cartons.

SVEN EBERLEIN, San Francisco resident: I go and travel somewhere, and I'm, you know, I have, like, eat an apple and where's the compost? You know, and I have to throw it in the trash, and it just doesn't feel quite right, you know.

SPENCER MICHELS: But not all San Franciscans are as enthusiastic as Eberlein and Baida. Those who refuse to sort their garbage can face fines ranging from $100 to $1,000.

WOMAN: So, we're just in the neighborhood trying to educate people on composting and recycling and answer any questions that you may have.

SPENCER MICHELS: Teams of workers from the city are knocking on doors of residents who, unbeknownst to them, have had their garbage cans inspected by auditors early in the morning. On the evening we followed along, outreach workers were visiting homes which had put items in the wrong bins.

WOMAN: We have noticed that there's been a lot of confusion about what goes in what bin, and so I'm here to offer any answers to any questions you may have.

WOMAN: I think we're pretty good with recycling. I guess, could you give me a rundown on what goes in composting?

WOMAN: If it was once alive and it's soil or food, then it is compostable.

WOMAN: OK.

SPENCER MICHELS: So far, only warnings have been given out. No fines have been imposed yet. And city officials say the move toward zero waste is catching on.

San Francisco's 80-year-old private garbage company, which recently invented a new name for itself, Recology, has been investing in recycling and composting facilities, and trying to change San Franciscans' perceptions of their garbage.

NARRATOR: Where some see garbage, Recology sees opportunity. Working together, we have helped make San Francisco America's greenest city.

MIKE SANGIACOMO, Recology: The biggest remaining fraction after we began recycling of the San Francisco waste stream was food waste.

SPENCER MICHELS: CEO and president Mike Sangiacomo took us on a tour of Recology's sprawling 22-acre composting facility northeast of San Francisco.

MIKE SANGIACOMO: In terms of food waste composting, this is as good as it gets. We're creating a product that can be used on the soil to replenish nutrients that growing food crops take out of the soil.

SPENCER MICHELS: Food scraps and yard clippings brought here, some 400 tons a day, are turned into rich compost that is now being used by vineyards in Napa and Sonoma. In the rest of the nation, where composting is a rarity, 97 percent of food waste is disposed of in landfills, and that causes environmental problems, according to regional EPA director Jared Blumenfeld.

JARED BLUMENFELD, Environmental Protection Agency: About half the food we buy from the supermarket ends up going into the landfill. That's unacceptable.

The stuff that rots and smells produces methane, which is a very, very potent greenhouse gas. And even if there's a cover on the top of just soil and stuff, that goes into the atmosphere and is really contributing in a large way to climate change issues.

SPENCER MICHELS: Beyond the environmental benefits of moving toward zero waste, Recology and city officials point to another perk: jobs.

At Recology's massive recycling center, which has been inundated the weeks after the holidays, 186 jobs have been created over the past 10 years.

Most of the sorting is done here by hand. Workers separate plastics, cardboard, cans and bottles, so they can be packaged and shipped to recycled material markets, mostly in Asia.

SPENCER MICHELS: For all the ballyhoo over San Francisco's recycling and composting programs, there are some skeptics. Some San Franciscans say that city officials haven't verified the rosy statistics.

QUENTIN KOPP, former California legislator: It's a myth. It's a bogus figure.

SPENCER MICHELS: Quentin Kopp, a former state and city senator, took part in an unsuccessful ballot effort last year to open the city's garbage contract to a competitive bidding process.

Kopp says Recology is inflating their recycling figures so they can boast that they are leading the nation.

QUENTIN KOPP: Yes, it is a good idea to recycle. It's also a good idea to be honest to the public about how much of the refuse and garbage in San Francisco is actually being recycled.

Nobody knows, except probably this company knows. They falsify the quantity. They falsify the type of material.

And it's part of a bogus scheme to inflate the amount of recycling done. And City Hall goes along with it, because it makes the politicians at City Hall look good.

SPENCER MICHELS: How do you know that 80 percent figure is accurate? Do you check it?

ED LEE: Yes, Spencer, we actually do. In fact, not only does our Department of the Environment go out and do audits. We actually have auditors that go out there and make sure that we're all in compliance with the way we measure it, and using the state standards and the state process to do it.

SPENCER MICHELS: So there's no doubt in your mind that the 80 percent is real?

ED LEE: Oh, no doubt at all, no doubt at all in my mind.

SPENCER MICHELS: Whatever the actual number is, recycling and composting don't come free.

Recology's Mike Sangiacomo:

MIKE SANGIACOMO: All of the services we provide are paid for by the customers whose material we're taking away.

SPENCER MICHELS: Are they paying more in rates because of all this recycling and composting than they would otherwise?

MIKE SANGIACOMO: I would bet they're paying a little more. But if you compare rates in the Bay Area, San Francisco vs. other communities, we're right in the middle of the pack. And we're doing a lot more recycling than any of the other communities.

SPENCER MICHELS: Residents currently pay about $28 a month for their trash bins. Recycling and composting bins are free.

But last month, Recology requested a rate increase, and for the first time wants to charge for composting and recycling bins, something the company says is necessary as the city moves toward eliminating its trash by 2020.

HARI SREENIVASAN: Spencer reflects on his trashy assignment, the moves by his city to reduce waste, and the financial factors at play behind the scenes. His blog is on our website.