To remove a sulfur odor efficiently by a small amount of a drug and to prevent the diffusion offensive odors and the corrosion of apparatuses by controlling the addition of a peroxide and/or nitrate ions based on the oxidation-reduction potential of a medium.
When sewage retained in a pit 102 in a pump site 101 reaches a definite level, the sewage is pumped up by a pump 111 to be supplied to a sewage treatment plant through a sewage pipe 112. The oxidation-reduction potential of the sewage is measured by oxidation-reduction sensor electrodes 103 and an oxidation-reduction meter 104. A measurement signal output from the meter 104 is input into a controller 105. Simultaneously, a flow rate signal is also input from a flow meter 110. The controller 105 calculates the amount of a drug to be added into the sewage by the signals and controls the actuation of a pump 106 for nitric acid and a pump 107 for adding hydrogen peroxide. In this way, a sulfur odor can be decomposed/removed by a small amount of the drug, and the corrosion of apparatuses can be prevented.
HAMAGUCHI TAKAYOSHI
OKAZAKI TADASHI
SHIMOMURA TADASHI
