| 摘要 |
<p>A two-stage sludge process for the purification of sewage. The process is less sensitive than those of the prior art but, nevertheless, succeeds in reducing the aeration time. The sewage is supplied to a higher loaded first activation stage, the sewage treated therein undergoes an intermediate settlement accompanied by the removal of sludge in the form of return sludge and surplus sludge, the intermediately settled sewage is fed to a lower loaded activation stage compared with the first activation stage and following final settling the material therefrom is drained off in pure form, wherein all the sewage is fed to a first aerated activation stage which is operated as a maximum load stage with a space load BR of approximately 10 kg BOD5/m3/day and a sludge load BTS of at least 2 kg BOD5/kg of dry substance/day, by intermediate settling of the sewage sludge mixture removed from the first stage a strict separation of the biocenoses of the two activation stages is ensured, whereby sufficient surplus sludge is removed from the intermediate settling stage that the age of the sludge is kept low, the intermediately settled sewage being fed to a second aerated activation stage which is operated as a low load stage.</p> |
