Settled solids are removed through pipes mounted on the rakes arms. Head differentials between the clarifier liquid level and the liquid level in the RAS collection box cause continuous flow through the sludge withdrawal pipes. Rake blades form pockets and direct sludge to where the uptake pipes are located.

Advantages:
• Telescoping valves in the collection box give operators the ability to observe, sample, and
  control the flow of solids removed from each individual uptake pipe.

• Rapid removal of settled solids
• Reduces denitrification flotation
• Adjustable sludge removal across tank floor