Method of bacteriostasis or disinfection for permselective membrane
AssigneeToray Industries, Inc.
InventorsTakuhei Kimura, Yuichiro Nakaoki, Yohito Ito, Yoshinari Fusaoka, Toshihiro Miyoshi
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Abstract
In the invention, the pipe lines around permselective membranes and the surfaces of permselective membranes are intermittently disinfected by adding an inexpensive acid such as sulfuric acid or the like to pre-treated crude water so as to make the water have a pH of 4 or lower. Accordingly, the invention provides a method of surely disinfecting the permselective membranes in membrane separation systems.
Claims11
A method of bacteriostasis or disinfection for permselective membranes in a membrane separation apparatus for water purification, which comprises subjecting crude water to acid treatment, while the membrane remains in operation, said acid treatment comprising a first acid treatment at a pH of from about 2.7 to about 4 and a second acid treatment at a pH of about 2.6 or lower.
A pre-treatment apparatus for a reverse osmosis membrane treatment apparatus, which comprises a first duct for feeding crude water to a sand filter, a second duct for feeding filtered crude water from the sand filter to a safety filter, a third duct for feeding filtered crude water from said safety filler to a reserve osmosis membrane apparatus means for maintaining continuous flow in the third duct by controlling the flow upstream thereof a flocculant feeder for feeding a flocculant to the first duct, a pH-controlling agent feeder for feeding a pH-controlling mineral acid to the second duct, and a microbiocide feeder for feeding a microbiocidal mineral acid to any one of the first, second or third ducts.
Dependencies are inferred from the claim text.