Method and apparatus for pulsed timed control for sludge return line

Claim 1

In a sewage treatment apparatus, an aeration chamber, a clarification chamber having a clear water zone, a sludge return line extending from the bottom of said clarification chamber to the top of said aeration chamber, an air service line supplying air from a blower to a lower portion of said sludge return line, apparatus for periodically pulsing air to said sludge return line comprising a solenoid controlled valve in said air service line to said sludge return line, timing means for periodically pulsing the air to said sludge return line so that eddy currents in the clarification chamber are reduced to retard flow of sludge into the clear water zone of the clarifier, and a metering valve downstream of said solenoid controlled valve to regulate the quantity of air supplied to said sludge return line when said solenoid controlled valve is opened.