Despite China's customs authorities placing a ban on the importing of plastic household garbage from overseas, large shipments still make it to the mainland, say analysts. The waste is usually smuggled in shipping containers mixed with industrial waste.

Like many other companies, the Yincun plant receives a steady supply of imported waste, which now makes up half of its business. In Liuzhen, a nearby village, almost all the plastic that is recycled is from abroad, China Daily discovered.

Although the price varies for different types of plastic, the plant owner in Yincun said imported waste is generally cheaper than domestic waste. In recent months, imported waste has cost about 3,000 yuan (US$440) a ton, although they are not separated by type, he explained. However, a ton of only mineral water bottles collected in Beijing is about 4,000 yuan. "Even if we have to take extra time to sort the bottles, the imported waste is still cheaper," he said.

As he runs a small operation, he usually hires migrant workers from other provinces to manually sort the plastic by polymer type or color. For example, bottles for fizzy soda drinks, such as Coca-Cola and Pepsi, are made of polyethylene terephthalate (PET), while bottles for orange juice, mineral water and shampoo are made of polyvinyl chloride (PVC).

"By burning the material with a lighter, and then smelling it and stretching it, we can easily determine what type of plastic it is. Sometimes we only need to take a bite of the plastic to find out," said the plant boss.

Without any formal training or even textbooks on the subject, this special know-how has for decades spread among people in Yincun through word of mouth.

After the plastic is sorted, it is smashed into small pieces and cleaned with caustic soda to remove any residue, such as oil and pesticides. Then it is ready for the mechanical recycling process.

In a family-run factory in the neighboring village of Lugezhuang, a 20-year-old worker surnamed Zheng stood over a run-down melting machine that produces polypropylene (PP) granules. Although the air in his small, dark room was choked with thick, pungent fumes, he seemed unbothered by the conditions. He spends 12 hours a day watching the machine make sure the temperature stays at around 200 C. "We produce about 2 tons of PP granules every day and the boss gives us about 70 yuan each," said Zheng, who got the job two months ago.

The machine turns the plastic into a thick, sticky liquid, which is then filtered into thin threads. Once these cool and become solid, they are finely chopped into small granules.

A plastics market has been running in Yincun since 1986 and, beginning at 6 am every day, people come to trade waste plastics and recycled products. Locals say the market hit a peak in the 1990s but, as more factories have secured their own supply and sales channels, trade has declined.

Plastics is not just a business in Wen'an county, it is a way of life. Villagers can be seen using plastic bottles to fuel fires for cooking, or to heat their homes. However, the health impacts of this practice have become a real concern, said residents across Wen'an county, many of whom claimed that the plastics industry is directly linked to an increase in the number of people with enlarged livers.