A siphon arrangement for removing sludge from the bottom of a sewage settling tank and discharging it into a sludge tank from which it is removed. The inlet of the siphon is submerged in the sewage adjacent the bottom of the settling tank and its outlet is submerged in the sludge discharged into the sludge tank. The siphon is carried by a float supported by the liquid in the settling tank, the level of which may vary as more or less sewage to be treated flows into the tank. The level of the sludge in the sludge tank will always be lower than the level of the liquid in the settling tank and it is important to the operation of the siphon to maintain constant this relationship of the levels of the liquids in the two tanks. This is accomplished by a control arrangement for controlling the discharge of the sludge from the sludge tank in accordance with variations in the level of the liquid in the settling tank.
A skimming apparatus for a liquid clarification tank that has an inlet for supplying liquid with suspended matter and an outlet for receiving clarified liquid and in which the outlet consists of longitudinally extending transversely spaced weir boxes that receive clarified liquid. The skimming apparatus is supported on a traveling bridge that is reciprocated between extreme positions along a path parallel to the weir boxes and extends transversely of the path of travel. The skimming apparatus consists of first and second portions that are respectively aligned with the weir boxes and the areas between the weir boxes. The first portions of the skimming apparatus are deflectable from a first position to a second position when the bridge traverses the area of the tank occupied by the weir boxes. The skimming apparatus is pivoted between operative and inoperative positions on the bridge and the first portions consist of elements pivoted to adjacent ends of the second portions that are rigid plates. The elements are biased to a first position and have camming members on the free ends for engaging tapered ends on scum baffles surrounding the weir boxes to move the elements from the first position when the bridge traverses the area of the weir boxes.
A solids remover for high rate algae ponds has a longitudinally extending pond within which there is a transversely extending settling basin, the settling basin having separate zones for the settlement of different solids. A carriage is supported for movement across the settling basin and carries pumping means. A nozzle arrangement on the inlet to the pumping means is effective to retrieve solids from any one or more of the separate zones and discharges the retrieved solids to a stationary solids receiver in any position of the carriage.
A sludge settling basin in which a platform is movable over the basin and supports a siphon tube having a first portion extending to adjacent the floor of the basin, a second portion extending over the basin and a third portion extending downwardly into the channel of the side wall of the basin, the material in the channel being removed by a pump with a sufficient rate for the level of liquid in the channel always to be below the level of liquid in the settling basin, so that the sludge is siphoned from the basin into the channel and is removed by the pump.
A method and apparatus for removing a varying depth layer of settled solids from the bottom of a sedimentation tank is disclosed. The apparatus includes a plurality of spaced eduction means supported on a bridge that is movable transversely between spaced inlets and outlets for the tank to remove settled solids from associated zones in the tank bottom. The apparatus further includes first means associated with each eduction means for providing a range of flow capacity between a minimum and a maximum for each zone and second means associated with each eduction means for adjusting the flow of sludge through the eduction means to remove all deposited solids from each zone during each pass of the bridge. A sensing mechanism cooperates with the second means to maintain a substantially uniform solids concentration in the sludge being removed by the respective eduction segments.
A sludge removal suction header is provided having an obtuse angled header shape and a much larger header cross section width dimension than presently utilized in the existing art. A longer width to height above ground ratio is produced which invokes ground effects. Internal annular passages are provided for equalizing the pressure distribution inside the header, thereby improving flow distribution across all holes, and especially those holes at the end of the header which are furthest away from the vacuum/suction source. An optimized number and diameter size of suction holes is further provided, as well as flow splitters, located beneath the header. Also, an air removal system is provided and placed for allowing vacuum to be provided by a controlled volume suction system, such as by a positive displacement pump, and in a manner that the positive displacement pump is allowed to maintain its prime, and air infiltration caused by startups is automatically removed, thereby reducing flow resistance inside the piping and providing more suction capability to the header.
