| 摘要 |
PROBLEM TO BE SOLVED: To efficiently suppress the formation of sulfide in a process for removing sulfide in sludge separated as the withdrawn sludge of a primary sedimentation tank and a post-treatment process of sludge by adding a nitrate to the withdrawn sludge of the primary sedimentation tank in a sewage treatment equipment. SOLUTION: Sulfide is formed by the action of sulfate reducing bacteria under an anaerobic atmosphere like the bottom part of a primary sedimentation tank or a treatment process for the withdrawn sludge of the primary sedimentation tank in a sewage treatment equipment and, when hydrogen sulfide is volatilized into the atmosphere, a malodor problem or a corrosion problem of the equipment is generated. Then, by adding an alkali metal nitrate or an alkaline earth metal nitrate to the withdrawn sludge of the primary sedimentation tank, the formation of sulfide is rapidly suppressed without increasing nitrogen load in the sewage treatment equipment. By adding an anthraquinone compd. along with a nitrate, the suppressing effect on the formation of sulfide can be continued and, as this anthraquinone compd., anthraquinone, anthrahydroquinone and an alkyl substituted compd. or hidride thereof are designated.
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