How Lamella Clarifiers Work
Courtesy of Parkson Corporation. The feed stream is introduced into the Lamella. Gravity Settler by means of a feed duct to the Lamella Gravity Settler feed box, which is a bottomless channel between plate scions.
In applications where coagulants and/or flocculating aids are used, flash mix and/or flocculation tanks can be supplied; they are mounted adjacent to the feed duct to avoid the possibility of floc breakup. The flow is then directed downward toward the individual, side-entry plate slots.
The feed is distributed across the width of the plates and then flows upward under laminar flow conditions. The solids settle on the plates while the supernatant exits from the plates through orifice holes. These holes are placed immediately above each plate and are sized to induce a calculated pressure drop to ensure that the feed is hydraulically distributed equally among the plates.
The solids, meanwhile, slide down the plates into the sludge hopper. Further thickening of the sludge is achieved in the hopper due to compression in the quiescent zone made possible by feeding the plates from the side rather than from the bottom. In some applications, a low amplitude vibrator pack can enhance thickening performance.
Design Criteria: Total effective settling area is based on projected area of each plate. The plates are proportioned to clarification and thickening area by adjusting the plate feed point. This ratio of clarification to thickening area is determined from laboratory settling tests of representative feed samples or, in cases where samples are not available, from past experience with similar applications. Plate spacing is 2"
The lamella clarifier unit is 18L by 9W by 12.5H (approx. weight is 20,000 lbs)there are three levels of plates, thus there could be 3 levels of tubes. FOB Utah.