METHOD AND DEVICE FOR TREATING ORGANIC WASTE WATER

PROBLEM TO BE SOLVED: To provide a method for treating organic waste water and a treatment device by which conventional problems are solved, the process or means of biological treatment is improved, and sludge can be dehydrated without adding a chemical for the improvement of the dehydrating property during dehydrating the sludge. SOLUTION: The method for treating organic waste water is carried out by introducing the organic waste water into aeration tanks 1, 2, 3, 4 to aerobically treat by active sludge, subjecting the suspension liquid sent from the aeration tanks to solid liquid separation in a sedimentation tank 5, and directly or indirectly returning the sludge settled in the sedimentation tank 5 to the aeration tanks while draining and dehydrating a part of the sludge as excess sludge. The above method and the treating device are characterized by that the amount of the returned sludge in the process of returning the sludge drained from the sedimentation tank 5 is 1.5 to 10 times as the amount of the organic waste water and that the excess sludge drained from the sedimentation tank 5 is condensed and then dehydrated by a filter press type dehydrating machine 9 having an electric osmotic function without adding a chemical effective for dehydration in an effective amount. COPYRIGHT: (C)2003,JPO