Everyone is familiar with the vending machine that spits out a can of coke or a bag of Skittles.

However, if you like cold, hard cash better than the cold, hard candy, here is another dispenser you might be interested in - the Reverse Vending Machine, which rewards users coins in exchange for their empty plastic bottles.

Residents use a reverse vending machine at a community in Beijing. Wang Jing / China Daily

Ten such machines, the size of big refrigerators, have appeared at major subways and bus stops within the Fourth Ring Road of the capital since the end of July, turning trash into treasure while encouraging the public to recycle and sort garbage.

Two thousand of them will be in place within the next two years, including 80 at colleges and universities, shopping malls, communities and office buildings, according to Chang Tao, director of INCOM, the producer of the machines.

"You get rewarded for recycling," said Chang. "People can also have the money donated if they wish."

The process starts with consumers casting their empties in the dispensers' feed unit. Plastic containers are identified by an imaging camera, compacted to less than one-third of the size and sorted into a built-in bin. The users can then get their monetary reward by scanning their metro card to the machine.

Better behavior

Widespread use of the vending machines could greatly encourage the public to sort trash and save natural resources, said experts.

"Despite the government's efforts in encouraging trash sorting, it has been poorly conducted in the city," said Chen Liwen, researcher with the Green Beagle, an environmental protection organization in the capital. "However, with monetary incentives, I guess the public will feel more motivated to do so."

When the machine is filled with bottles, its data center will inform the company's head office, located in the capital's Shunyi district. Nearby packing stations will send workers to have them collected, packed and sent to the headquarters.

The data center can also identify other sorts of trash besides plastic bottles, such as waste paper, and spit them out, Chang said.

When the pilot project is working well in the capital, the company will further expand its service in the economically developed cities, including Shanghai, Suzhou, Wuxi and Hangzhou, and later nationwide.

Chang said the service will also cover other items, such as tin cans, to turn more trash into treasure and take full advantage of the natural resources.

Better treatment

Most beverage bottles are made of PET, or polyethylene terephthalate, that can be recycled, maintaining its value and reducing the waste going to landfills, to make new bottles.

According to Mao Da, an expert in solid-waste management at Beijing Normal University, PET, which is also used in pharmaceutical products, is one of the most valuable of the some 40 plastics.

"Many governments and waste collection agencies worldwide encourage people to separate the waste PET bottles from other plastic waste, so it can be collected and made into bottles again," he said. "It loses its recyclable value if made into clothes or even non-food containers, like basins, though many workshops in Zhejiang province are doing that for profit," he said.

According to Chang, unlike the small workshops, which transfer the plastic bottles into clothes and bags, all the plastic bottles they get will be made into bottles again.

"It definitely makes more profit to turn the bottles into clothes, yet it is a waste of resources, and a drop in the long-term value of it, since the clothes will take 100 years to degrade," said Chang. "Turning the waste plastic bottles into new bottles shows respect to nature."

People believe they have the waste recycled as long as the empty bottles are handed to scavengers, which Chang said is not necessarily true.

Of the 20-some tons of waste bottles produced in the capital annually, Chang said, only about 3 to 5 tons end up in Chang's recycling station - most of the rest ends up in small workshops.

Besides wasting resources, the underground workshops are seriously polluting the environment, Mao said.

To reduce cost, the illegal workshops simply clean the bottles with groundwater and discharge the polluted water onto the ground, polluting the soil.

Chang said even in the capital, there are some 300 such workshops around the Sixth Ring Road.

"The land around the workshops has turned barren from the alkaline water they discharge into the ground without neutralizing treatment," said Chang. "No residents around the workshops dare to drink the local water for fear of poisoning.

"They are doing more than devaluing the resources," he said.

According to Chang, the capital has a very progressive attitude toward recycling, and the technology, once popularized, will greatly encourage people to recycle at or around shopping malls, subways or by the roadside.

Jobs replaced

According to Mao, China, unlike other countries, has continued to rely on scavengers for waste recycling and resource utilization, and the State-run recycling stations are gradually disappearing from the country.

"The scavengers have greatly eased the nation's task in trash disposal," he said.

However, despite their contribution, he believes the junkmen are driven by profit, and their recycling work sometimes pollutes and wastes resources, he said.

Chang agrees. "Many empty bottles we collected from individual scavengers are filled with stones or dirty water, to increase the weight for extra profit," he said. "Replacing them with the intelligent machine will ensure a sufficient supply of empty bottles of higher quality."

But worries arise over how to deal with the unemployment of people who make their living collecting copper wire and coke cans, because they will be replaced by machines.

According to Chen, there are some 200,000 scavengers in the city and the development of the machines could suddenly cost them their incomes and possibly even result in social disorder.

However, Ren Lianhai, a professor at Beijing Technology and Business University's environmental science and engineering department, said the possibility of social unrest is low.

"This is a very flexible group of people," he said. "Besides, to deploy the machines nationwide will require time, which will be long enough for them to find a new job or go to another city for the waste."

Ren said there are for the moment labor shortages in a number of fields in the city.

"The machines have been put to use in some countries for years, like Brazil and Japan," he said. "It would be beneficial for the country's recycling economy in the long run."

Contact the writer at zhengxin@chinadaily.com.cn