| 摘要 |
<p>PURPOSE:To increase microbes in an aeration tank of a fixed bed type in which sewage is circulated in upward current and to improve the efficiency of purification by supplying activated sludge into said tank and maintaining the volume of the activated sludge in the tank at 30-70%. CONSTITUTION:Sewage is supplied from a distributor 1 through a piping 2 to an aeration tank A. The tank A consists usually of a body tank 3 constituted of concrete or the like, in the lower part of which an aeration chamber 4 is formed ed. A gravel layer 6 is formed in the upper part of said chamber and aeration pipes 5 are installed in the chamber 4 from the upper part thereof. The tank is required to be so constituted that the aeration is accomplished from the lower part of fixed filter beds and that the water to be treated is circulated in upward current with respect to the fixed beds. Then, the surfaces of the fixed beds are vulnerable to live of microbes as films of living things, and even if the volume of the sludge is made 30-70%, the suspended state of the activated sludge is maintained satisfactorily.</p> |
