In the last 30 years the economic progress in China was considerable.Modem metropolises such as Beijing or Shanghai grew with fast pace,causing amongst others a rapidly increasing water consumption which means in turn a rapid increase of waste water to be discharged as sewage.Currently in China only half of the sewage is properly treated,because the old sewage cleaning systems are not capable to cope with the large amounts of polluted water,as a consequence the polluted water is drained into rivers without treatment; at the same time there is a lack of clean water.