A data base of adsorption from aqueous solution onto CAL activated carbon has been determined for 157 organic compounds at 25°C. These data are expressed by Freundlich adsorption equation. To predict the adsorption data of the other compounds, a prediction method using Adsorbability Index (AI) is examined. AI is composed of A and I ; these are determined from the data base. A represents the factor which increases adsorbability of a functional group or atom in a molecule. I represents the factor which inhibits adsorption. The AI value of a given molecule can be obtained by adding the A and I values of all atoms and functional groups in the molecule. A good linear relationship is obtained between the Freundlich adsorption constant log K and AI of the 157 compounds (the correlation coefficient is 0.986). The A and I indexes determined from the data for CAL activated carbon can be applied to predict log K for the other activated carbons.

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Turbidimeters are frequently used as one of the methods to measure continuously the amount of suspended solids (SS). In practical use, wastewater is mostly colored according to its properties. In this study, changes of the turbidimeter indications due to the coloring of dispersant in suspensions were examined under various conditions by changing such facters as optical methods, the particle sizes, the concentrations of SS and coloring matters. The following three optical methods were adopted to measure SS ; (a) measuring the scattered light flux with an integrating sphere (method A), (b) measuring the ratio of scattered light flux to total light flux with an integrating sphere (method B), (c) measuring the ratio of scattered light flux to transmitted light flux without integrating sphere.
1) The method A shows the largest change in those three methods, but the method B is scarcely influenced by the coloring of dispersant. The method C shows little change for coloring suspensions whose spectral transmittances are not dependent on wavelength.
2) The effect of the coloring of dispersant appears more clearly in case of more dilute concentration of SS and larger particle size.
3) The suspensions colored by methylene blue show a larger change in the indication than that by eosin.

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The principal objective of this investigation was to study the effects of temperature on organic matter removal in aerobic digestion. Chemostat-type bench-scale experimental reactors were used in this study. Digestion times were 6.7, 10, 15, 20 and 30 days. Digestion temperature were 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C. The following conclusions can be drawn from the experimental results. At temperatures ranging from 10°C to 35°C, the digestion time longer than 15 days is needed to obtain the high substrate removal efficiency, while at a temperature of 5°C, the digestion time longer than 20 days is needed. The rate of sludge production from utilized BOD₅ decreases as digestion temperature and time increase. This rate is rather small than that of conventional activated sludge. However, the amount of refractory organic compounds prodused in endogenous respiration markedly increases as digestion temperature and time increase.

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[in Japanese]

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