気泡曝気による旋回流式曝気槽の表面流速と酸素移動性能について : 曝気槽の総括酸素移動容量係数算出法とその応用に関する研究 (第5報)

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Effects of air flow rate, diffuser submergence, diffuser location and kind of diffuser on the surface velocities were studied in both pilot scale and industrial scale spiral flow aeration tanks.1. Using the dimensional analysis method, the following equation was derived : ((V_S・H)/υ)=C((G_S/V・H^2)/υ)^α(h/H)^b where V_S=surface velocity, H=water depth, G_S=air flow rate, V=tank volume, υ=kinematic viscosity coefficient, h=diffuser submergence and C, a and b=constants.2. The above equation was experimentally satisfied in both single spiral flow system and double spiral flow system. Constants C, a and b wre changed with kinds of diffusers and diffuser locations.3. The ove-all oxygen transfer coefficient, K_La was correlated with the surface velocity, but regression lines changed with both diffuser submergence and locatioin.4. The surface velocity decreased with the increase in the viscosity of mixed liquor.5. The surface velocity with plate diffuser was higher than that with sparger at a given air flow rate.6. It was suggested that the surface velocity could be predicted using the equation for the pumping velocity of an air-life pump. And it was expected that the surface velocity could be used for the scale-up of the spiral flow aeration tank.
公益社団法人日本生物工学会の論文
1975-09-25