WASTE LIQUID TREATING METHOD BY PRESSURE FILTER AND ITS STORAGE AT NON-USING TIME

• Main Authors: NAKAMURA HIROSHI, KAKIMOTO AKIRA, NISHIO HIRONORI, WAKUTA KUNIHARU
• Format: Patent
• Language: English
• Published: 20.10.1998
• Edition: 6
• Subjects: PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; TRANSPORTING

PROBLEM TO BE SOLVED: To prevent clogging of filter cloth of a pressure filter to maintain the efficiency of the pressure filter so that a reduction in cost can be achieved by reducing the frequency of replacement of filter cloth by treating waste liquid by means of the pressure filter by adding chemicals to the waste liquid to be treated. SOLUTION: When a filter system, into which organic matters easily penetrate, is operated, in a pretreatment, aqueous solution 4 of copper acetate is injected into waste liquid to be treated 2 in a tank 1 from a chemical tank 3 to adjust the concentration of copper ion in a mixture of the waste liquid 2 and the solution 4 to about 10 ppm and the waste liquid is agitated. Next, the liquid 2 pretreated is fed to a pressure filter 7 to filter it, and for storing the filter 7, when the operation thereof is suspended, the solution 4 of a concentration of about 10 ppm of copper ion is injected into the filter 7 from the tank 3 and backwash water is returned to the tank 1 through a backwash line. And after the backwashing, a valve is closed to fill the filter 7 with the solution 4 to store it.