| 摘要 |
<p>PURPOSE:To greatly reduce excessive sludge generation by separating activated sludge after applying activated sludge treatment to organic sewage, adding alkaline agent to the sludge, aerating it under alkaline conditions and thereafter recycling the sludge to an activated sludge treatment process. CONSTITUTION:Sewage 1 is introduced into an aeration tank 2 of an activated sludge treatment process to be aerated in the presence of BOD metabolizing bacteria and then is sent to a solid-liquid separation process 4 to be separated to separated sludge 5 and treated water 6. A part 7 of the sludge 5, as excessive sludge, is fed to a sludge dehydration process 8 to be dehydrated, while the remainder 9, major part of the sludge, undergoes aeration in a return sludge aeration tank 11 under alkaline conditions, wherein alkaline agent 10 such as NaOH is added thereto, and then the sludge 9 is recycled to the aeration tank 2 through a line 12. In this manner, generation of excessive sludge can be greatly reduced and sedimentation and concentration of activated sludge is improved and further feed air rate for an activated sludge aeration tank can be reduced, thereby producing energy saving effects.</p> |
