1992 年 28 巻 p. 29-37
Effect of temperature and hydraulic retention time (HRT) on the characteristics of acidogenesis in anaerobic digestion were investigated using anaerobic chemostat-type reactor, which soluble starch was fed as a substrate.
The HRTs were 0.25d, 0.5d, 1.0d and 2.0d. The experimental temperature was changed in the rangefrom 10°C to 30°C. The degradation efficiency of the substrate and the composition of volatile fatty acids (VFA) produced in anaerobic acidogenesis were significantly affected by the temperature and HRT. The necessary HRT for obtaining the high degradation efficiency of 95% at the temperature ranges of 20°Cto 30°C and 10°C to 20°C were 1.0d and 2.0d, respectively. At the condition that the temperature ranged from 20°C to 25°C and the HRT rangedfrom 1.0d to 2.0d, the COD yields of various products to the influent substrate in the reactors ranged in the following percentage; VSS: 20 to 22%, VFA: 41 to 54%, Others: 9 to 30%, H2: 6 to 12% and CH4: 0.4 to 0.8%. The effects of temperature and HRT on the distribution of acidogenc bacteria, homoacetogenic bacteria, acetate-consuming methanogenic bacteria and H2-consuming methanogenic bacteria were studied by enumerating the bacterial population levels. From this investigation, it was elucidated that the complete phase separation of acidogenesis and methanogenesis was possible by conducting the acidogenesis below the temperature of 25°C.