Clarifying tank for waste water treatment - with central air lift pump in settling cone as sludge stirring mechanism

摘要

A clarifying device for a water treatment plant has a clarifying section and a settling cone arranged in the same tank. The stirring mechanism in the settling cone consists of an air lift pump. Its pump tube includes two separate pipes in the centre line of the tank which end in the plane dividing the clarifying from the settling section. The waste air is carried away in a central pipe through the clarifying section which overlaps with its bottom end the top pump tube. The stirring mechanism does not disturb the clarifying process, yet it keeps a homogeneous sludge in circulation even during its discharge operation.