To provide a method of operating an oxidation ditch capable of sufficiently and surely performing not only the decomposition and nitrification reaction of organic matter in sewage but also the denitrification reaction thereof as well.
The method of operating an oxidation ditch which is provided with a water tank 1 which stores a liquid mixture 2 composed of sewage and activated sludge, a partition wall 10 which forms a waterway 20 of an endless type in the water tank 1, an aerator 3 which is disposed on one end 10a side portion of the partition wall 10 in the waterway 20 and forms circulation flow in the waterway 20 by aerating the liquid mixture 2 while stirring the liquid mixture, and a stirring device 4 which is disposed on the downstream side of the aerator 3 and forms the circulation flow. The method is characterized by operating the aerator 3 in such a manner that the dissolved oxygen concentration measured by a dissolved oxygen meter 5 disposed in the water tank 1 attains a prescribed value and alternately performing an aeration step of putting the entire part of the liquid mixture 2 in the water tank 1 to an aerobic state and an anaeration step of stopping the airator 3, and of putting the entire part of the liquid mixture 2 in the water tank 1 into an anaerobic state.
MIZUGUCHI TARO
SATO MIKIO
ITO NOBUMOTO
Shiro Terasaki
Noriaki Nagahama
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