Patents Assigned to Lemna Corporation
  • Patent number: 6136194
    Abstract: A wastewater treatment system substantially reduces wastewater treatment time and increases treatment capacity. The system includes at least one completely covered aerobic reactor cell and a completely covered quiescent anaerobic reactor cell. The system can also include a polishing reactor for further treating wastewater after treatment by the anaerobic reactor cell. The covered aerobic reactor cell preferably includes a pair of subcells in which a first cell includes continuous mixing and aeration of the wastewater and the second cell includes only intermittent mixing and aeration of the treated wastewater. The system optionally includes a completely covered anoxic reactor cell for treating wastewater prior to treatment by the completely covered aerobic reactor cell. The anoxic reactor cell receives partially treated wastewater recirculated from the polishing reactor. Growth media can be used in the reactor cells to enhance biological activity.
    Type: Grant
    Filed: January 19, 1999
    Date of Patent: October 24, 2000
    Assignee: The Lemna Corporation
    Inventors: Steven M. Vogel, Surya R. Pidaparti
  • Patent number: 5861095
    Abstract: A wastewater treatment system substantially reduces wastewater treatment time and increases treatment capacity. The system includes at least one completely covered aerobic reactor cell and a completely covered quiescent anaerobic reactor cell. The system can also include a polishing reactor for further treating wastewater after treatment by the anaerobic reactor cell. The covered aerobic reactor cell preferably includes a pair of subcells in which a first cell includes continuous mixing and aeration of the wastewater and the second cell includes only intermittent mixing and aeration of the treated wastewater. The sytem optionally includes a completely covered anoxic reactor cell for treating wastewater prior to treatment by the completely covered aerobic reactor cell. The anoxic reactor cell receives partially treated wastewater recirculated from the polishing reactor.
    Type: Grant
    Filed: April 9, 1997
    Date of Patent: January 19, 1999
    Assignee: Lemna Corporation
    Inventors: Steven M. Vogel, Surya R. Pidaparti
  • Patent number: 5736047
    Abstract: A hybrid system and related process for the removal of biological nutrients from wastewater. The system provides an activated sludge system, including both a single-sludge reactor and clarification unit, flowably connected with a final aquaculture pond for final polishing of BOD from the clarified mixed liquor supernatant.
    Type: Grant
    Filed: May 4, 1995
    Date of Patent: April 7, 1998
    Assignee: Lemna Corporation
    Inventor: Viet H. Ngo
  • Patent number: 5534141
    Abstract: A wastewater treatment system for deployment in a body of water having a floor and a water surface includes an in-pond clarifier extending across the body of water. The in-pond clarifier defines a clarifying chamber and includes an upper portion and a lower portion. The upper portion is suspended above the wastewater surface. The lower portion is maintained adjacent to the floor of the body of water. As a result, the body of water is divided into distinct treatment zones on opposite sides of the clarifying chamber. The in-pond clarifier further includes a plurality of pumps for removing biological solids which settle within the clarifying chamber. Separate pumps are provided for either returning settled solids to the body of water or for wasting settled solids from the body of water.
    Type: Grant
    Filed: December 9, 1994
    Date of Patent: July 9, 1996
    Assignee: The Lemna Corporation
    Inventors: David W. McAnaney, John R. Dorner
  • Patent number: 5421999
    Abstract: A floating nitrification reactor for use in a treatment pond utilizes a mass of high surface area material which provides sites for bacterial treatment. Floatation devices are attached to the mass of high surface area material in order to float the material at neutral buoyancy while an isolator surrounds the material and isolates the material from the rest of the treatment pond. An aerator, located a distance below the mass of high surface area material, forces air and water through the material at a sufficient speed to allow treatment.
    Type: Grant
    Filed: July 25, 1994
    Date of Patent: June 6, 1995
    Assignee: The Lemna Corporation
    Inventors: Warren D. Poole, David J. Burton
  • Patent number: 5409601
    Abstract: A floating aquatic plant water treatment system (31) utilizes a serpentine channel (36) defined by dividing walls (34). Floating plants (72) are distributed across the water surface by a floating grid structure (32). The grid structure (32) is preassembled into Z-fold bundles (88) which are towed onto the water and unfolded. The treatment system uses sprayers (62) to control growth conditions. Porous baffles (46) are placed along portions of the channel (36) to provide intimate contact with a larger portion of the water while allowing free flow.
    Type: Grant
    Filed: July 6, 1993
    Date of Patent: April 25, 1995
    Assignee: The Lemna Corporation
    Inventors: Viet H. Ngo, Warren D. Poole, Sean J. Hancock, Timothy T. France
  • Patent number: 5338452
    Abstract: An anaerobic reaction system for treatment of a continuous flow of wastewater comprises a wastewater inlet, a first anaerobic reactor connected to the inlet, a second anaerobic reactor connected to the inlet and parallel to the first reactor, and a split box between the inlet and the first and second reactor. The split box channels the continuous flow of wastewater to the first reactor and to the second reactor. Effluent empties from the first reactor while wastewater in the second reactor is anaerobically reacted upon and clarified. Alternately, effluent empties from the second reactor while wastewater contained in the first reactor is anaerobically reacted upon and clarified.
    Type: Grant
    Filed: January 14, 1993
    Date of Patent: August 16, 1994
    Assignee: The Lemna Corporation
    Inventor: Surya R. Pidaparti
  • Patent number: 5264127
    Abstract: A floating aquatic plant water treatment system (31) utilizes a serpentine channel (36) defined by dividing walls (34). Floating plants (72) are distributed across the water surface by a floating grid structure (32). The grid structure (32) is preassembled into Z-fold bundles (88) which are towed onto the water and unfolded. The treatment system uses sprayers (62) to control growth conditions. Porous baffles (46) are placed along portions of the channel (36) to provide intimate contact with a larger portion of the water while allowing free flow.
    Type: Grant
    Filed: December 11, 1992
    Date of Patent: November 23, 1993
    Assignee: The Lemna Corporation
    Inventors: Viet H. Ngo, Warren D. Poole, Sean J. Hancock, Timothy T. France
  • Patent number: 5256281
    Abstract: A sewage treatment pond has an inlet for introduction of sewage into the pond and an outlet for removal of sewage from the pond. A first baffle extends from the surface of the pond to the bottom of the pond and between the inlet and the outlet. The first baffle has an opening located a first distance from the surface of the pond so that sewage can pass through the opening. A second baffle is located between the inlet and the outlet. The second baffle extends from the surface of the pond to the bottom of the pond. The second baffle has an opening located a second distance from the surface of the pond.
    Type: Grant
    Filed: June 20, 1991
    Date of Patent: October 26, 1993
    Assignee: The Lemna Corporation
    Inventors: Viet Ngo, Gary L. D'Heilly
  • Patent number: 5235797
    Abstract: Aquatic plants are harvested from a body of water. The aquatic plants are gathered from the surface of the body of water and transported to a collection zone at a collection point on the body of water. The aquatic plants are then moved from the collection zone to an aquatic plant processing station.
    Type: Grant
    Filed: February 13, 1992
    Date of Patent: August 17, 1993
    Assignee: The Lemna Corporation
    Inventors: Victor V. Sygen, David J. Burton, Lawrence J. DeVore
  • Patent number: 5197263
    Abstract: A duckweed slurry is recovered from a body of water. The duckweed slurry includes duckweed and water from the body of water. The duckweed slurry is transported to a dewatering station. A majority of the water from the duckweed slurry is removed at the dewatering station. Water removed from the duckweed slurry is returned to the body of water.
    Type: Grant
    Filed: September 13, 1991
    Date of Patent: March 30, 1993
    Assignee: The Lemna Corporation
    Inventors: Brian J. Midtling, Lawrence J. DeVore, Victor V. Sygen
  • Patent number: 5180501
    Abstract: A floating aquatic plant water treatment system (31) utilizes a serpentine channel (36) defined by dividing walls (34). Floating plants (72) are distributed across the water surface by a floating grid structure (32). The grid structure (32) is preassembled into Z-fold bundles (88) which are towed onto the water and unfolded. The treatment system uses sprayers (62) to control growth conditions. Porous baffles (46) are placed along portions of the channel (36) to provide intimate contact with a larger portion of the water while allowing free flow.
    Type: Grant
    Filed: June 20, 1991
    Date of Patent: January 19, 1993
    Assignee: The Lemna Corporation
    Inventors: Viet H. Ngo, Warren D. Poole, Sean J. Hancock, Timothy T. France
  • Patent number: 5161354
    Abstract: A harvester for harvesting aquatic plants includes a rotatable gate. The rotatable gate subdivides a containment area which is used to hold harvested aquatic plants. The rotatable gate acts to compress harvested aquatic plants and increases harvest capacity.
    Type: Grant
    Filed: May 10, 1991
    Date of Patent: November 10, 1992
    Assignee: The Lemna Corporation
    Inventors: Victor V. Sygen, David M. Anderson, Lawrence J. DeVore
  • Patent number: 5096577
    Abstract: A floating aquatic plant water treatment system (31) utilizes a serpentine channel (36) defined by dividing walls (34). Floating plants (72) are distributed across the water surface by a floating grid structure (32). The grid structure (32) is preassembled into Z-fold bundles (88) which are towed onto the water and unfolded. The treatment system uses sprayers (62) to control growth conditions. Porous baffles (46) are placed along portions of the channel (36) to provide intimate contact with a larger portion of the water while allowing free flow.
    Type: Grant
    Filed: March 17, 1989
    Date of Patent: March 17, 1992
    Assignee: The Lemna Corporation
    Inventors: Viet H. Ngo, Warren D. Poole, Sean J. Hancock, Timothy T. France
  • Patent number: 4536988
    Abstract: The present invention relates to a floating containment barrier grid structure (20) for containment of floating aquatic plants (26) in a body of water (30). The barrier grid structure (20) includes a plurality of interconnected square barrier segments (24), the top edge of the barrier segments extending above the surface of the water so as to prohibit substantial wave action. The floating containment barrier grid structure (20) being anchored by cables (38) and stakes (40) in a somewhat tensioned state while floating in the body of water (30). The barrier grid structure (20) being tensioned to enable portions of the barrier grid structure (20) to be submerged beneath the surface of the water by a harvesting machine (28) while harvesting the floating aquatic plants (26).
    Type: Grant
    Filed: January 31, 1984
    Date of Patent: August 27, 1985
    Assignee: The Lemna Corporation
    Inventor: Delman R. Hogen