After walking half a block just to put an empty water bottle in a waste bin marked "recycle," you might be forgiven for feeling relaxed about your role in helping to save the planet.

A man sorts empty plastics bottles into different categories at a garbage recycling plant in the suburbs of Huaibei, a city in Anhui Province. China consumes 52 million tons of plastics a year. [China Daily]

But do you know where that bottle goes?

If you live in Beijing, Tianjin or any other city in north China, the chances are that once it is collected by one of the many independent "junkmen" and sold to a waste collection business, the bottle ends up in Wen'an County, Hebei Province.

About 120 km south of Beijing, Wen'an is the largest cluster of family-run plastics recycling businesses in north China. From its humble beginnings in Yincun Village in the 1970s, the industry has evolved into a mature chain: from sorting and cleansing, to melting, shredding, granulating and molding.

However, this is not the clean, green process most people would picture. This is the dirty world of recycling.

Residents in Wen'an told China Daily that the pollution created by this "sustainable" industry is seriously affecting their health and has even made them afraid to drink the water, which many believe is severely contaminated.

Traveling through the county, it is impossible to miss the large advertising boards that line roads. Nearly all say in big, bold letters things like PE, PS, PVC and PP, which describe to those in the know the kinds of plastics different companies handle.

There are several hundred varieties of plastics. It is difficult for outsiders to tell the difference but we can," said the middle-aged boss of a small plant who did not want to be identified.

The courtyard at his plant is cluttered with heaps of waste plastics, some in big sacks, others squashed into a cube. Among the piles were empty bottles of engine oil and Nivea body milk, medicine bottles, tubs of yogurt, pesticides containers, as well as fragments of plastic bathtubs and fruit baskets.

"They are from two different channels. The plastic in sacks is from nearby cities or provinces, while the plastic in compressed cubes has been shipped in from other countries," explained the boss.