Method for membrane separation

[Problem] To efficiently prevent permeation-membrane clogging at low cost with a small chemical amount to stably treat water for long while preventing membrane deterioration and trihalomethane generation, even when the water contains a large number of viable cells and is in a highly slimy condition....

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Bibliographic Details
Main Authors Nakamura, Taeko, Matsumoto, Katsumi, Kowata, Kenji
Format Patent
LanguageEnglish
Published 05.12.2019
Subjects
CHEMISTRY
METALLURGY
PERFORMING OPERATIONS
PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
SEPARATION
TRANSPORTING
TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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Summary:[Problem] To efficiently prevent permeation-membrane clogging at low cost with a small chemical amount to stably treat water for long while preventing membrane deterioration and trihalomethane generation, even when the water contains a large number of viable cells and is in a highly slimy condition. [Solution] When water to be treated in which the viable cell number (logCFU/mL) is 3 or larger is treated by membrane separation while intermittently adding a combined-chlorine agent which contains a sulfamic acid compound, the following periods are repeated: a non-addition water-supply period in which the water is supplied for 6-120 hours without adding the combined-chlorine agent; and an intermittent-addition water-supply period which is conducted in the beginning of biofilm formation and in which the water is supplied for 0.5-40 hours while adding the combined-chlorine agent in a concentration sufficient to remove the biofilm. During the intermittent-addition water-supply period, the concentration of the combined-chlorine agent is regulated to 0.5-20 mg/L in terms of total chlorine concentration.
Bibliography:Application Number: AU20120278599