US 12,319,601 B2
Apparatus and method for biological treatment of organic wastewater
Toshihiro Tanaka, Tokyo (JP); Kiyomi Kabasawa, Tokyo (JP); and Yasuharu Sato, Tokyo (JP)
Assigned to EBARA JITSUGYO CO., LTD., Tokyo (JP)
Appl. No. 17/285,612
Filed by EBARA JITSUGYO CO., LTD., Tokyo (JP)
PCT Filed Oct. 17, 2019, PCT No. PCT/JP2019/040862
§ 371(c)(1), (2) Date Apr. 15, 2021,
PCT Pub. No. WO2020/080460, PCT Pub. Date Apr. 23, 2020.
Claims priority of application No. 2018-195964 (JP), filed on Oct. 17, 2018.
Prior Publication US 2021/0395122 A1, Dec. 23, 2021
Int. Cl. C02F 3/12 (2023.01); B01F 23/231 (2022.01); B01F 25/50 (2022.01); C02F 1/00 (2023.01); C02F 3/20 (2023.01)
CPC C02F 3/1278 (2013.01) [B01F 23/2311 (2022.01); B01F 25/50 (2022.01); C02F 1/006 (2013.01); C02F 3/20 (2013.01); C02F 2001/007 (2013.01); C02F 2201/007 (2013.01); C02F 2203/006 (2013.01); C02F 2209/08 (2013.01); C02F 2301/026 (2013.01); C02F 2301/046 (2013.01); C02F 2303/06 (2013.01)] 8 Claims
OG exemplary drawing
 
1. An apparatus for biological treatment of organic wastewater, comprising:
a first biological treatment tank having a fixed-type immobilized biocarrier and an air diffusing means that is arranged on a lower side of the fixed-type immobilized biocarrier;
a second biological treatment tank having an air diffusing means into which treated liquid that has been treated in the first biological treatment tank can be introduced so as to be treated by suspended microorganisms without using a biocarrier;
a sedimentation tank where solid-liquid separation can be carried out on a mixed liquid that has been treated in the second biological treatment tank so that the mixed liquid can be separated into sedimented sludge and treated water;
an inflow line through which organic wastewater can be introduced so as to be distributed into the first biological treatment tank and the second biological treatment tank;
a return sludge line for returning part of the sedimented sludge that has been discharged from the sedimentation tank to the second biological treatment tank;
a flow amount adjustment mechanism for adjusting distribution amounts of the organic wastewater that is to be distributed to the first biological treatment tank and the second biological treatment tank;
a first BOD sensor configured to measure a BOD value in the organic wastewater; and
a second BOD sensor configured to measure a soluble BOD value of the treated liquid within the second biological treatment tank, wherein
the flow amount adjusting mechanism is operatively connected to receive sensor data from the first and second BOD sensors,
the flow amount adjustment mechanism is configured to adjust distribution amounts of the organic wastewater that is to be distributed to the first biological treatment tank and the second biological treatment tank in response to the sensor data from the first and second BOD sensors,
the flow amount adjustment mechanism adjusting a supply amount of the organic wastewater to the second biological treatment tank to set a ratio Y (%) of a supply amount of the organic wastewater that can be supplied to the second biological treatment tank to a total supply amount of the organic wastewater to satisfy the following Formula 1 with a BOD volume load X (kg/m3/d) of an entirety of the first biological treatment tank and the second biological treatment tank being in a range of 0.5 or greater and less than 0.814, and to satisfy the following Formula 2 with X being in a range of 0.814 or greater and 1.5 or less, wherein
5≤Y<−63X+82.5   (Formula 1)
5≤Y<−20X+47.5   (Formula 2).