Roy Derrick maneuvered his forklift with a pallet of neatly boxed expired produce and flowers and dropped it into an industrial compactor at Safeway's cavernous return center in Upper Marlboro, Maryland. As the compactor hummed, compressed food and floral scraps spilled through a chute into a 12-meter trailer, one of five that would make the weekly trip to composting centers in Delaware or Virginia.

Employees at 125 Safeway stores along the East Coast ship everything from flowers to coffee grounds and spoiled vegetables to the Maryland center, which then must transport the waste at least another 150 km to be recycled into compost.

It illustrates composting's complicated trajectory in the United States. The movement is inching forward in fits and starts, by entrepreneurs as well as by community activists and civic leaders, but the nation's trash disposal system lacks the ability to process food waste on a large scale. Food scraps are also heavier than aluminum cans, making them more expensive to transport.

But increasingly, local governments, entrepreneurs and community activists are experimenting with composting.

Last month, Washington Mayor Vincent Gray announced that the city's Office of Planning was awarded $600,000 in grants to build three to four compost sites for urban farms or community gardens in the city to test composting methods.

Howard County, Maryland, has collected food waste from 1,000 households since September 2011 as part of a pilot program; officials are launching a composting site this spring at the county landfill so that scraps won't have to be hauled to Delaware. And a small composting operation has opened up in Baltimore in an industrial warehouse.

Freestate Farms, an agricultural consulting company, is working to launch a compost facility in Northern Virginia.

"It's been under the radar screen until now, and seen as a boutique, West Coast thing," said Jared Blumenthal, who oversees California as well as two other Western states and the Pacific for the Environmental Protection Agency. "But now everyone from Massachusetts to Minnesota has programs starting up, and pretty soon there will be a critical mass."

Environmentally minded city leaders have adopted "zero-waste" pledges, noting that traditional trash disposal not only wastes material that can enrich soil but accelerates climate change. Organic matter decomposing in landfills accounts for 16.2 percent of the nation's emissions of methane, a potent greenhouse gas. Vermont, Connecticut and Massachusetts are all phasing in bans on putting commercial food waste in landfills.

Although composting can work for large institutions ranging from hospitals to universities and hotels, which can save money by selling organic waste to third-party operators rather than paying to dump it in a landfill, it is more of a challenge on a smaller scale.

"We're finally at a point of figuring out how to make money through organics," said Compost Cab founder Jeremy Brosowsky, who charges his 400 residential customers in the District of Columbia $32 a month to collect their food scraps, which he gives away to local farms and gardeners.

"This is an area that holds a lot of promise," said Harriet Tregonig, who heads the D.C. Office of Planning. "It's letting, really, nothing go to waste."

Right now, the United States is years away from achieving that vision. More than 170 communities across the country in 18 states have some sort of residential food scrap recycling program serving at least 2.3 million households, according to Rhodes Yepsen, who tracks the industry for the magazine BioCycle. That is up from 20 programs in 2005 and does not include private programs such as Safeway's, but it is still a small fraction of the country's population.

Americans generated nearly 35 million tons of food waste in 2010, according to the EPA, 97 percent of which went into landfills. By contrast, more than 60 percent of the nation's yard trim — which makes up a similar portion of the U.S. waste stream — got recycled.

Putting grass cuttings and leaves out on the curb, of course, is more palatable than depositing rotting fruit, crushed eggshells and vegetable peelings. And compost collectors have a limited number of places to deposit their hauls, especially in dense urban areas with expensive real estate.

Many communities in the areas have contracts with waste incineration sites, making it harder to develop organic recycling sites.

"The interest is growing, but there's not enough places to take it and put it," said Brenda Platt, who promotes composting for the D.C.-based Institute for Local Self-Reliance.

Jack Jacobs, director of distribution of Safeway's eastern division, said he prefers not to ship it so far away. But it still makes "good business sense" for the company, he said. Safeway pursued composting "because of our environmental sensibility. We knew it was the right thing to do."

In the past, major trash industry operators such as Waste Management have sometimes fought government requirements to divert waste because they operate landfills, and they get paid according to how much trash they put there. But these same firms are now investing in organic recycling, in part because of customer demand. Waste Management — the nation's largest waste hauler, disposal and recycling company — operates 36 organic processing facilities across the country and has invested in companies such as Harvest Power, which takes solid waste from municipalities in the United States and Canada and converts it into high-quality soils or energy.

"We certainly believe it's becoming mainstream, and in some parts of the country, it's been mainstream for a while," said Waste Management's director of organic recycling, Eric Myers, whose firm just opened a state-of-the-art composting facility in Orlando, Florida.

Still, Myers said it is too soon to jettison traditional waste disposal altogether.

"Why not ban food waste? Why not ban landfills?" he asked. "Well, it's not sustainable."

Government officials overseeing the most successful programs in the country, however, say public policy has played a critical role in boosting organic recycling rates. Back in 1989, California passed a law to divert half of its waste from landfills by 2000. San Francisco has taken it further by diverting 75 percent of its trash by 2010, and now aims to achieve zero waste by 2020.

San Francisco's commercial zero-waste coordinator, Jack Macy, said the fact that the city charges residents and business based on how much trash they generate, known as "pay as you throw," has helped boost recycling rates.

Portland, Oregon, by contrast, opted in October 2011 to change its garbage collection program so haulers now take away green waste — including food scraps — once a week but pick up other trash only once every two weeks. In a single year, the city cut its residential trash load by 40 percent.

Not all politicians have embraced this trend. Democrats introduced composting to the House of Representatives' cafeteria in 2007 after winning the majority, only to see House Speaker John Boehner jettison the policy in 2011 once Republicans regained control of the chamber.

"The good news is that battle doesn't tell us where the country stands, it tells us where the Republicans are as an ideological mindset," said Rep. Earl Blumenauer.

In some ways, composting is a "reactionary" concept rather than "a new idea," said Jonathan Bloom, author of the book "American Wasteland." Bloom grew up in Massachusetts, where many residents used to deposit their food scraps in a pail encased in a cement sleeve outside the back door until the early 1970s. Pig farmers picked it up to use as slop.

Sumner Martinson, director of the Massachusetts Department of Environmental Protection's composting program, remembers putting those scraps outside his parents' home as a child. Now he spends his time explaining to state residents why it is worth composting again. "It will happen, but it will take a whole lot of education," he said.