A truck loaded with trash climbs a mountain of garbage, scattering a hoard of vultures. As it spills out its load, men and women reach into the stream for tin cans, plastic bottles, paper _ anything they might sell _ as the vultures swoop back in, fighting for scraps of food.

This landfill, one of the world's largest, operates 24 hours, seven days a week, taking in more than 9,000 tons of garbage daily from Rio de Janeiro and four other cities. With organized recycling still in its infancy in Brazil, most salvaging of reusable materials from Rio's trash happens here, through the heavy, dirty work of about 5,000 "catadores," or trash pickers.

After decades of anonymity, the workers of the Gramacho Municipal Landfill have been catapulted to fame by a collaboration with Brazilian artist Vik Muniz, who used the trash they sort to create portraits of the pickers. A documentary recording that experience is now vying for an Oscar.

On Feb. 27th, the recyclers plan to watch the awards show from the community of plywood, tin and cardboard shacks where many of they live, a short walk from the dump.

"I can't say this is a dream that's come true, because who would have imagined this?" asked Luciana dos Santos, a former trash sorter who now is financial director of the workers association at Gramacho.

Even as the workers enjoy their moment in the spotlight, they're steeling themselves for change many of them have long feared: the closure of the landfill. Built on unstable, ecologically sensitive marshland in 1977, Gramacho was long blamed for polluting Guanabara Bay, and it is running out of space.

Three days after the Oscars ceremony, the first load of trash will go to a state-of-the-art facility that meets stringent new environmental regulations, but has no room for the catadores. By December, Gramacho will be closed, transformed into a biogas facility.

The money raised through their collaboration with Muniz has helped many of the catadores prepare by establishing worker-run recycling co-ops. For many others, whose only jobs have been sorting through trash, the closure will be traumatic.

Things first started changing for the catadores when Brooklyn-based Muniz visited the dump in 2007, seeking elements to use in his next project. Muniz, born into a Brazilian working class family, is known for art that incorporates materials from dust to diamonds. Often the elements themselves carry a message, as when he created portraits of the children of sugarcane cutters out of sugar itself.

The documentary, born of a chance meeting between English filmmaker Lucy Walker and Muniz, followed the artist's collaboration with the recyclers over three years.

Muniz took photos of the workers in epic poses that drew from their own experiences, reproducing, for example, Jacques-Louis David's "The Death of Marat" and Pablo Picasso's "Woman Ironing." The image was blown up until it filled the floor of a warehouse-sized studio. Trash was used to fill in the details, giving it color and texture. The final result, an image so large it had to be seen from above, was then photographed.

The documentary shows how the catadores start to see themselves differently as they help build their own portraits.

Suelem Pereira Dias, who started working in the dump when she was 7 years old and was supporting two children by the time she was 18, had seen few if any pictures of herself before, said Muniz.

When she and others suddenly see their own faces rendered larger than life, they are moved to tears. The experience also gives some of the participants enough distance from their daily grind to start imagining a life away from the stench of the landfill.

"It was a very strong, emotional situation," said Muniz. "The fact that they had worked on it and the fact that that image was made with nothing but the stuff that they deal with every day, that for me was the most important thing."

In addition to the Oscar nomination, the documentary won the Sundance Film Festival Audience Award for Best World Cinema Documentary and nearly two dozen other film festival awards.

Through the sale of the portraits, Muniz raised $300,000 for the association and the recyclers who worked with him. That money paid for an office, a storage shed to sort materials and management classes. Soon they had their own recycling cooperatives, and were gearing up to work in a new system in which trash will be sorted in households, and recycling plants will replace catadores.

No one, least of all the workers, disputes that their current work is dangerous and unsanitary.

They don't earn much: 10 cents per kilogram of cardboard, 14 cents per kilogram of glass. But many hours of work and hundreds of kilos later, it's a living. For some, it's the only job they've held in lives of few opportunities and much bad luck.

In Gramacho, children learned from their parents how to differentiate materials, including 14 different types of recyclable plastic, by touch and sound so they can work into the night, when deliveries ramp up.

Sueleide Portela da Silva, 21, started working alongside her mother, who toiled at Gramacho for 25 years until she lost her eyesight to trash falling from a truck.

By 14, Silva had her first child. At 15, pregnant again, she started working at the dump, along with three of her sisters. None of them attended school beyond 4th grade.

"People are very afraid," she said of the dump's closure. "Most people here can't read properly, and every job out there, they want you to have high school, college."

Wearing denim shorts over hot pink tights, torn fishnets and boots, Silva hauls up to 680 pounds (310 kilograms) of paper a day. She specializes in printer paper. It earns her only 13 cents a kilo if clean, 11 cents if dirty, but it's a lighter load. On a good day, she'll take home $40.

Once the landfill closes, Gramacho's 5,000 trash pickers and sorters will qualify for unemployment benefits and government training to work in recycling plants.

The landfill itself will also be a source of income for the workers.

The Rio city government has installed 230 wells to tap the carbon dioxide and methane gases that emanate from the rotting waste. About 1.9 million tons of carbon dioxide will be captured annually _ as much as 1.4 million gasoline-powered cars exude a year _ making it the largest greenhouse gas capturing project in Brazil and one of the largest in the world.

Sales of the gas for energy production and carbon credits are expected to generate about $244 million over 15 years. The workers will get 18 percent of that, said Gramacho manager Lucio Vianna Alves.

The money will go into a fund to be managed by the mayor of Duque de Caxias, the town where the landfill is located, in a partnership with the workers' association.

In spite of the promised benefits, many catadores are still afraid of the day they'll be forced out of Gramacho. After a lifetime of living at the margins, they don't trust they'll see any of the funds.

But others say they are ready.

"The catadores are aware. They know the time of the dump is over," said Nilson Jose dos Santos, the son of a trash picker who has worked at Gramacho for 28 of his 44 years.

"The city is implementing recycling at the source, and there will be no more work for the catadores," Santos said. "It's time for change, and we have to be part of that change."