| 摘要 |
<p>PURPOSE:To enhance fermentation efficiency and to advance the fermentation of a digested sludge solution to such a degree that secondary purifying treatment becomes easy by providing a heating means to the side wall part of a fermentation tank composed of a vertical cylindrical container, and providing a convection accelerating means for sending out content upwardly along the side wall of the fermentation tank to the bottom part of said tank. CONSTITUTION:Each of fermentation tanks a1-a3 is composed of a vertical cylindrical container whose height is three times or more the square root of the cross-sectional area thereof. The liquid to be treated introduced into the fermentation tank a1 is subjected to convectional circulation in the fermentation tank a1 by a convection accelerating means e1 and a heating means f1. This liquid to be treated is circulated through the follower reaction tower b1 provided together with the scum breaking means g1 provided to the upper part of the fermentation tank 1a to be further homogenized. By this method, fermentation reaction is efficiently advanced. When the new liquid to be treated is introduced into the fermentation tank a1 from the lower part thereof, the fermentated liquid is transferred to the fermentation tank a2 of the next stage from the upper part of the fermentation tank a1 in the amount corresponding to that of the new liquid to be treated. Fermentation is advanced in the fermentation tank a2 of the second stage in the same way and the fermented liquid is transferred to the fermentation tank a3 of the third stage, if necessary. By this method, a digested sludge solution is obtained.</p> |
