Abstract: Enhancements to the Double Drain technology used for separation of settle-able solid wastes previously developed. Anti-vortex fins are added to the central clarified effluent water manifold to minimize re-suspension of settled solids. A further aspect includes the addition of a slotted horizontal cover plate to a solid waste collection sump below the tank floor. These additions significantly increase the effectiveness of the Double Drain system for separation of settle-able solid waste from fish culture water. The enhanced Double Drain Tank design with the anti-vortex feature could also be used in non-fish culture applications to enhance the separation of settle-able solids from any liquid waste water flow.

Abstract: Disclosed is a bioreactor apparatus having a bed of buoyant media pellets floating within a filtrate to be processed. The apparatus includes a tank (22) having a peripheral wall for containing filtrate (34) and a bed (36) of media pellets (38). A central manifold (100) is rotatably supported within the tank, the central manifold being mounted for rotation about a vertical axis (22) and having a plurality of longitudinally spaced openings (140) intermediate its ends, the openings adapted to eject filtrate in a generally horizontal direction and along a substantially vertical plane toward the wall of the tank, cyclically fluidize pellets in a directly narrow zone. In a preferred aspect, there is also a thrust manifold (140), generally parallel to the axis of the central manifold and having a plurality of longitudinally spaced openings intermediate its ends directed horizontally and generally perpendicularly to the plane.