Beijing has a 200,000-strong army of recyclers and garbage collectors, who dispose of 20 million residents' waste.

Sun Youzhi is one of them. The 29-year-old from Henan province's Gushi county has a small recycling business in a residential area near the Bird's Nest - the 2008 Beijing Olympics' main stadium.

"There are a lot of tourists around here," Sun says.

"I collect a lot of empty water bottles."

He has spent 10 hours a day collecting waste around his residential area for the past four years.

"People sell water bottles, but few know where they end up," Sun says.

He buys waste from local residents and garbage collectors. Sun transports his waste every evening to a scrap market 6 km away, in suburban Dongxiaokou town.

Dongxiaokou is Beijing's largest waste trading center. Scores of collectors deal in waste paper, scrap metal, plastic and foam.

Waste is sorted and processed in the town. Waste paper dealers buy old books to sell to flea markets. Old newspapers are sorted and sent to paper mills, while paper cartons end up in packing stations.

Dealers compress and shred water bottles. They sell the material to chemical plants in neighboring Hebei province, where it's turned into polyester threads used to make clothes.

"The polyester in our T-shirts is very likely from water bottles," says Sun, who once worked in a plastic-shredding plant.

The country's first recycling stations were established shortly after New China's 1949 founding. Goods were scarce then.

The stations were owned and run by the State. But most shut down amid national economic reforms and urbanization.

Most garbage collectors and recyclers in cities today are migrant workers.

About 98 percent of the capital's 120,000 registered recyclers come from three provinces - Henan, Anhui and Hebei - the Beijing Resource Recycling Association reports.

The actual figure is more like 200,000 if the unregistered are counted, says Beijing University of Technology researcher Cheng Huiqiang, who specializes in the economics of recycling.

Some recyclers take trash from the city's streets, while others go door-to-door.

Some, like Sun, run their own businesses.

China Resource Recycling Association vice-secretary-general Fu Hongjun says: "The recyclers are efficient. They work very hard transforming trash into treasure for themselves and the country."

Sun's family of nine depends entirely on recycling. His parents work for a water bottle dealer, who pays them to remove caps and labels from bottles before they are recycled. His brother-in-law works with him. Both have children.

Sun and his brother-in-law collect an average of 3,000 empty water bottles, a ton of waste paper, 100 kg of iron scrap and nearly 200 kg of plastic waste a day.

They each earn about150 yuan ($25) a day.

"We've made less money this year because the economy is gloomy," Sun says.

"But it's still better than returning to our hometown."

About 4.67 million tons of recyclable waste was collected from the 6.35 million tons of trash Beijing produced in 2010, municipal government figures show.

Cheng views recycling as saving. Recycling a ton of waste paper can save three cubic meters of timber. One ton of scrap metal can be processed into 0.8 tons of new metal.

Cheng says 3 million tons of empty water bottles are thrown away in China a year. If all these were recycled, 18 million tons of crude oil could be saved, he says.

"In that sense, there are invisible oil fields, forests and mines in the cities," Cheng says.

China Features