| 摘要 |
After the V-phase (presedimentation) and before the R-phase (stirring) sedimented, thickened activated sludge from the SU-tank (sedimentation and circulation tank) is recycled (S-phase) into the B-tank (activated sludge tank). Preferred features: Recycling is effected during or preferably after the A-phase (extraction). The volume with lower dry matter than introduced sedimented activated sludge displaced in the S-phase in the B-tank, is recycled through openings close to the surface into the SU-tank. These only permit flow in the S- and R- phases, and are closed in the V- and A- phases. The openings are closed with flaps. These open automatically during the greater differences in level between the B- and SU- tanks during the S- and R- phases.With reduced water level differences in the B- and A- phases they remain closed. Stirring in the SU- tank (R-phase) is effected by air injection, or by electrically-driven stirrers. Recycle of sedimented and thickened activated sludge is effected in the S-phase by a compressed air lift pump or by electrically-driven stirrers. Further similar variations are described, and processing durations and levels are detailed. |
