Envirex Inc.

Evoqua Water Technologies Pte. Ltd.

Donald J Thiel

George W Smith

John W Wittmann

Allen Lepak

Jeffrey P Germait

Govardhan R Katta

An apparatus for wasting flocculant sludge from a clarifier is provided including a wasting pipe fluidly connectable to a waste conduit, a manifold fluidly connectable to the wasting pipe, an upper header for collecting the flocculant sludge fluidly connectable to the manifold, a return sludge pipe fluidly connectable to a return sludge well, a lower header for collecting settled sludge fluidly connectable to the return sludge pipe, and a drive mechanism for rotating the upper header and the lower header about a center axis. A wastewater treatment system is provided including the clarifier fluidly connectable to a source of a mixed liquor and the apparatus for wasting flocculant sludge. A method of separating settled sludge from a clarifier is provided including withdrawing flocculant sludge and withdrawing settled sludge. A method of retrofitting a clarifier is also provided including providing the manifold, the upper header, and the drive mechanism.

Sludge withdrawal mechanism for wasting and returning settled sludge from secondary clarifier with granular sludge

In an orbal wastewater treatment process including a plurality of concentric, annular basins or channels having surface aeration means, wastewater and recycled activated sludge are mixed in a first channel by a combination of the surface aeration means and introducing an oxygen-containing gas such as air into the lower portion of the zone under conditions which produce a complete mix reaction and sufficient oxygen is supplied to meet the biological oxygen demands of the mixed liquor. The gas is introduced, preferably by a plurality of fine bubble membrane diffusers, in the form of fine bubbles having a diameter of less than about 4 mm. The mixed liquor is sequentially oxidized in second and third channels by a combination of surface aeration means and introducing an oxygen-containing gas into the lower portions of the channels, preferably by fine bubble membrane diffusers.

Orbal wastewater treatment process

Wastewater and recycled activated sludge are homogeneously mixed in a first aeration zone by injecting an oxygen-containing gas such as air into the lower portion of the zone under conditions which produce a complete mix reaction and sufficient oxygen is supplied to meet the biological oxygen demands of the mixed liquor. The gas is introduced, preferably by a plurality of fine bubble membrane diffusers, in the form of fine bubbles having a diameter less than about 4 mm. The bubbles provide both the mixing to keep solids in suspension and the oxygen required to maintain the overall dissolved oxygen content in the first aeration zone as close to 0 as possible. The mixed liquor is sequentially contacted with an oxygen-containing gas in second and third aeration zones under conditions which produce a complete mix reaction, preferably by fine bubble membrane diffusers, clarified and a portion of the settled sludge is recycled to the first aeration zone.

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Waukesha, WI, United States of America

Donald J Thiel