| 摘要 |
PROBLEM TO BE SOLVED: To avoid the anaerobic condition of the sewage even when a force-feed pump is stopped for a long time, to suppress the concentration of hydrogen sulfide constantly below a specified level irrespective of the fluctuation of the quantity of the force-fed sewage, to reduce the installation space of an oxygen generator, and to suppress the power consumption. SOLUTION: In this method for suppressing generation of hydrogen sulfide in a sewage pumping pipe by injecting oxygen gas into the force-fed sewage in an interlocking manner with the operation of a force-feed pump, the reference rate of operation, the rate of operation rising time when the rate of operation of the force-feed pump is started to exceed the reference rate of operation, and the rate of operation falling time when the rate of operation of the force-feed pump is started to fall below the reference rate of operation are set based on the rate of operation fluctuation pattern of the force-feed pump with one day in one cycle, the time at the specified time before the rate of operation falling time is set as the excessive oxygen feed starting time, and oxygen gas of the quantity larger than the specified value corresponding to the quantity of the pumped sewage is excessively injected in the sewage in the time zone when the time reaches the rate of operation rising time after reaching the excessive oxygen feed starting time. One control system is selected depending on the required oxygen injection into the sewage pumping pipe to selectively operate the whole or a part of the adsorption tank units PSA2-PSAa(n), and to feed the required quantity of compressed air corresponding to the required oxygen injection.
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