抄録
The decomosition of sludge brings not only the decrease in the sedimentation and the recovery of solid material at gravity thickener, but also the decrease in the efficiency throughout the process of further treatment. With our recognition of the significance in the prevention system of decomosition, we have found that vacuous process of sludge prevents its decomposition, and we have confirmed its practicability in the actual device, in addition, the device can be successfully simplified. The efficiency of this device, especially in the primary sludge and exess sludge, and appropriate example at a small scale sewage treatment plant have been reported in this article.
