blank Decades of industrial growth along China’s Huai River have polluted water supplies for 180 million people.  Its banks are lined with so-called Cancer Villages afflicted with cancer rates ten times the national average. An innovative water purification system developed by researchers at Beijing University is changing that, one village at a time.

The system collects rainwater, then filters it through three stages of purification, each removing different contaminants. The water produced meets the Chinese standard for drinking water. Rainwater is a cleaner water source than river or ground water.  This allows the purification system to be simple and inexpensive.

Teams of students from the university build these purification systems and teach the villagers how to operate and maintain them.Unfortunately, this type of purification system will remove some larger contaminants from the water, but will leave smaller pollutants, dissolved hydrocarbons and metals,  which are toxic and more dangerous.