Abstract: A wastewater treatment system having a tank, a rotatable surface aerator and an elongate draft tube is presented. The elongate draft tube is at least partially submerged beneath the liquid and is rotated about its longitudinal axis for orbitally moving the liquid through the tank in a fixed direction. The rotatable surface aerator is coupled to the proximal end of the draft tube and is at least partially immersible into the liquid. The system further can provide an anoxic zone. A process for treating wastewater is also provided.

Abstract: A wastewater treatment system, comprising a tank and an elongate draft tube. The tank comprises a bottom and at least one partition wall extending short of a tank curved turning wall to form at least a pair of channels for movement of a volume of a liquid. The elongate draft tube is at least partially submerged beneath the liquid and is rotated about its longitudinal axis for orbitally moving the liquid through the at least a pair of channels of the tank in a fixed direction. A process for treating wastewater is also provided.

Abstract: A wastewater treatment system, including a tank and an elongate draft tube. The tank includes a bottom and at least one partition wall extending short of a tank curved turning wall to form at least a pair of channels for movement of a volume of a liquid. The elongate draft tube is at least partially submerged beneath the liquid and is rotated about its longitudinal axis for orbitally moving the liquid through the at least a pair of channels of the tank in a fixed direction. A process for treating wastewater is also provided.

Abstract: An impeller having flexible impeller blades with a stiffness which allows the blades to flex into a backward-curved impeller configuration at the maximum intended rotational speed of operation, and to return to a more radial blade configuration at lower rotational speeds, thereby enabling efficient operation at a broad range of rotational speeds.

Abstract: An apparatus for rotating a drum employs a plurality of drive sprockets disposed about the outside surface of the drum and spaced-apart along the length of the drum. Each drive sprocket has a first flange, a second flange, and a plurality of pins interconnecting the first flange and the second flange, spaced-apart about the drum and parallel to the axis of the drum. Spaced-apart hydraulic rams each exert force on one of the drive sprockets so as to cause rotation of the drum. Each ram is moveable between a linearly retracted first state and a linearly extended second state and has a first end and an opposite second end. The first end is secured to the base, the second end is engageable with the pins of a selected drive sprocket so that as the ram extends from the first state to the second state, the ram exerts force on a pin in the first direction, the first direction being tangential to the outside surface and perpendicular to the axis of the drum.

Abstract: An apparatus for aerating a liquid, having a surface, employs a motor having a rotating member and a non-rotating member. A shaft is coupled to the rotating member of the motor. Also coupled to the shaft is an input of a planetary gear assembly, comprising stationary upper portion and a rotatable lower portion. The rotatable lower portion is coupled to the axial section of an aeration rotor so that as the aeration rotor is placed in the liquid, a portion of the planetary gear assembly is in contact with the liquid, thereby facilitating cooling of the planetary gear assembly by the liquid. The planetary gear assembly also comprises a seal between the stationary upper portion and the rotatable lower portion disposed above the liquid and disposed above substantially all of the oil in the planetary gear assembly so as to inhibit spillage of oil from the planetary gear assembly into the liquid if the seal fails.

Abstract: A reaction vessel for biologically decomposing a material comprises a frame, an airtight housing rotatably mounted on the frame defining an enclosure therein, and a device for controlling environmental conditions within the enclosure so that biological decomposition of the material can occur at a controlled rate. Air is circulated through the enclosure in a closed loop so that air leaving the enclosure will be recirculated back into the enclosure. A computer controls the oxygen level of the air inside the enclosure, the humidity of the air inside the enclosure, the temperature of the air inside the enclosure, and the carbon dioxide level of the air inside the enclosure. The housing is disposed at an incline relative to the frame so that the material introduced into the enclosure proximal to the higher portion of the housing tends to flow toward the lower portion of the housing. A separating wall is disposed within the enclosure, forming therein a first chamber and a second chamber.

Abstract: An apparatus for biologically decomposing a material, comprising a frame and a substantially airtight housing rotatably mounted on the frame is disclosed. The housing has a first outside surface and a first inside surface, a first end and a second end, the first inside surface defining an enclosure therein. The housing also defines a plurality of openings therethrough. A first air header supplies air to, and a second air header removes air from, a plurality of air manifolds disposed external to the housing and in fluid communication with the enclosure through the openings defined by the housing. The plurality of air manifolds includes a first plurality of air manifolds in fluid communication with the first air header and a second plurality of air manifolds in fluid communication with the second air header. Air passes from the first air header through the first plurality of air manifolds into the enclosure and passes out of the enclosure through the second plurality of manifolds to the second air header.