PURPOSE: To purify high-concn. waste water to low-concn. waste water, to deodorize and decolorize malodorous colored polluted water and simultaneously to sterilize harmful bacteria by passing waste water through a ceramics layer.

CONSTITUTION: Polluted waste water is introduced to a first tank, and passes through the ceramics layer A provided between the first tank and a second tank. Consequently, the BOD, COD and SS(suspended solid) in the waste water are reduced. The waste water is allowed to overflow the second tank, and a specified amt. of a chlorine agent is charged into a third deodorizing and decolorizing tank. The waste water is deodorized, decolorized and sterilized therein, and further passes through the layers of ceramics B, C and D laminated on one another. The org. matter is adsorbed by the layers, and the waste water is further deodorized. Further, the waste water passes through the ceramics layer E provided at the lower part of the fourth and fifth tanks to remove impurities, and passes through the sixth tank. The residual chlorine in the waste water is removed in the sixth tank, the concn. is perfectly decreased, and the treated water is discharged into a drainage ditch.