OZONE TREATMENT OF ACTIVATED SLUDGE METHOD TREATED WATER

摘要

PROBLEM TO BE SOLVED: To suppress the generation of excessive sludge, in treatment wherein activated sludge is drawn out of an activated sludge treatment system is treated with ozone and the treated sludge is introduced into the activated sludge treatment system, by treating the treated water high in soluble COD from the activated sludge treatment system in a rear stage by together using ultraviolet irradiation and ozone treatment. SOLUTION: In a treatment method for activated sludge treated water equipped with an activated sludge treatment system for sewage 1, an ozone treatment system for sludge and an ozone treatment system for water, the sewage 1 is treated with activated sludge while air is supplied from the air diffuser 4 in a biological reaction tank 2 and the treated sewage is subjected to solid-liquid separation treatment in a final sedimentation basin 3. The sludge is returned to the biological reaction tank 2 as return sludge 6 but a part of the sludge is sent to an ozone treatment tank 10 for sludge to be treated with ozone to be introduced into the biological reaction tank 2. The water passed through the final sedimentation basin 3 flows in an ozone treatment tank 13 for water in a state high in soluble COD and is irradiated with ultraviolet rays from an ultraviolet lamp 12 while ozone 9b is added from an ozone generator 8 to be subjected to ozone oxidizing treatment.