| 摘要 |
PURPOSE:To remove easily, economically and efficiently COD from water contg. bisulfite to be discharged from a reverse osmosis membrane separator for desalting by dispensing an alkali agent to said water under aeration of said water. CONSTITUTION:Condensate is introduced into the 1st tank 1a and the pH thereof is measured with pH 6a, and if the pH decreases to <4, a pump 7a is started to supply an alkali agent via a pipe 8a to the water to adjust the pH to 4-7 and to treat the water for 5-10min. The water is then introduced into the 2nd tank 1b, where the water is treated for 60-120min under the condition of 4-7pH to oxidize most of the bisulfate in the water. The treated water is introduced into the 3rd tank 1c, where the pH is maintained in a 6-8 range and the residual bisulfite ion and sulfite ion are finally treated to make the treated water match the level of the release water. The water in the tank 3 is stagnated for 5- 30min. COD is thus considerably reduced and the treated water is released from the 3rd tank to the outside of the system.
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