US 12,246,290 B2
Membrane filtration device and method for cleaning membrane filtration device
Shintaro Nishimoto, Amagasaki (JP); Keishi Watanabe, Amagasaki (JP); Tetsuya Uenaka, Amagasaki (JP); Fang Zhao, Amagasaki (JP); and Akira Matsunaga, Amagasaki (JP)
Assigned to KUBOTA CORPORATION, Osaka (JP)
Appl. No. 17/417,623
Filed by KUBOTA CORPORATION, Osaka (JP)
PCT Filed Dec. 12, 2019, PCT No. PCT/JP2019/048609
§ 371(c)(1), (2) Date Jun. 23, 2021,
PCT Pub. No. WO2020/137564, PCT Pub. Date Jul. 2, 2020.
Claims priority of application No. 2018-243845 (JP), filed on Dec. 27, 2018.
Prior Publication US 2022/0111336 A1, Apr. 14, 2022
Int. Cl. B01D 65/02 (2006.01); B01D 63/00 (2006.01); C02F 1/44 (2023.01)
CPC B01D 65/02 (2013.01) [B01D 63/00 (2013.01); C02F 1/44 (2013.01); B01D 2317/04 (2013.01); B01D 2321/04 (2013.01); B01D 2321/12 (2013.01); B01D 2321/18 (2013.01); C02F 2303/16 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A method for cleaning a membrane filtration device including multiple membrane separation units, with each unit being vertically on top of one another, and each unit being a stage, wherein each of the membrane separation units has a primary side communicating with a backwash drainage system and a flushing-air supply system so as to receive supplied raw water and a secondary side communicating with a backwash-water supply system so as to collect permeate, the membrane separation unit performing membrane filtration and cleaning, wherein the cleaning includes:
supplying flushing air into the primary sides of the membrane separation units through the flushing-air supply system while supplying backwash water into the secondary sides of the membrane separation units through the backwash-water supply system; and
draining backwash drain water of a gas-liquid mixed fluid from the primary sides of the membrane separation units through the backwash drainage system, wherein the backwash water is supplied downward into a backwash-water main pipe of the backwash-water supply system and is fed into the membrane separation units of the stages through backwash-water branch pipes connected in parallel to the backwash-water main pipe, wherein the flushing air is supplied upward into an air main pipe of the flushing-air supply system filled with raw water supplied in the membrane filtration, wherein the flushing air flows upward in the raw water of the air main pipe into a plurality of air branch pipes connected in parallel to the air main pipe and is fed into the membrane separation units of the stages through the air branch pipes substantially simultaneously, and wherein the backwash drain water is drained from the membrane separation units of the stages into backwash-drainage branch pipes of the stages and flows downward from the membrane separation units of the stages substantially at the same time in a backwash-drainage main pipe connected in parallel to the backwash-drainage branch pipes of the stages.