摘要：This paper describes the results concerning the effects of various disinfectants on the oxygen uptake rate (OUR) of activated sludge (AS). To start with, in vitro inhibitory effects of four test disinfectants : STERIHYDE[○!R], HYAMINE-T[○!R], ISODINE[○!R] and HYPAL No.20[○!R], on OUR of two kinds (AS-A ; Kamaboko fishcake industrial waste water and AS-B ; local municipal sewage) of AS were determined by the previously mentioned method. The IC50 values of thirty-three kinds of typical disinfectants were measured for AS-A, respectively. GRINCE[○!R], termed 2, 4, 4'-trichloro-2'-hydroxydiphenyl ether (0.3% Irgasan DP 300), and Irgasan DP 300 alone, inhibited most strongly by the IC50 values of 6 mg/l, respectively, and followed by Cetylpyridinium chloride (20 mg/l), OSVAN[○!R] (58 mg/l), HYAMINE-T[○!R] (58 mg/l), Potassium permanganate (60 mg/l), Thimerosal (65 mg/l) and Benzethonium chloride (80 mg/l). However, with Phenol, Suponated cresol, Resorcin, Silver nitrate, Medical soap, Bronopol and Acrinol, the concentration of these disinfectants which results in the IC50 value were over 1000 mg/l. In addition, the toxic effects on OUR of AS in the presence of an equivalent mixture of two disinfectants tend to become stronger than that of the disinfectant alone. Namely, the additive effects of OUR-inhibition seemed to exist (For example ; Saponated cresol-STERIHYDE[○!R], HIBITANE[○!R]-GRINCE[○!R] etc.).
关键词：activated sludge;toxicity;oxygen uptake;disinfectants;IC50 value
