NOVELTY - Apparatus includes a first manifold (100) with spaced openings (140), a thrust manifold (150) having openings (156), supports (142,144) to hold the thrust manifold relative to the first manifold (100) so that the openings (156) eject fluid perpendicular to openings (140). The manifolds are rotated by filtrate ejected from the thrust manifold openings.    USE - Used to filter dissolved wastes in water, to digest organic wastes or to produce pharmaceuticals.    ADVANTAGE - The manifold design is simple, inexpensive and reliable. The pellets are small to maximize surface area per unit volume while providing adequate mass for buoyancy. The manifolds may be structured for retrofitting in existing bioreactors.    DETAILED DESCRIPTION - Apparatus used with a bioreactor tank (22) having a bed of media pellets (38) to be fluidized and for treating filtrate (34) in the tank through biofilm adhering to the pellet, comprises:    (1) an elongate first manifold (100) having longitudinally spaced openings (140) along its length which are aligned and in a longitudinal plane extending radially outwardly of the first manifold;    (2) an elongate thrust manifold (150) having openings (156) along its length which are aligned and in a longitudinal plane extending radially outwardly of the thrust manifold;    (3) means (142,144) to support the thrust manifold in association with the first manifold so that the plane of openings in the thrust manifold is perpendicular to the plane of openings in the first manifold;    (4) a supporting means also supporting the thrust manifold rearward of the plane of openings of the first manifold in the direction of the thrust manifold openings;    (5) means (102, 104) associated with the first manifold for mounting the first manifold for rotation within a bioreactor tank and means (70, 72, 78, 80) for communicating filtrate under pressure to the first manifold and thrust manifold.    Filtrate ejected from the first manifold openings fluidizes pellets adjacent to the thrust manifold so that manifolds are rotated by filtrate ejected from the thrust manifold openings.    DESCRIPTION OF DRAWING(S) - The figure shows an elevation view of the bioreactor.    Media pellet (38)    First manifold (100)    Openings in first manifold (140)    Supports (142, 144)    Thrust manifold (150)    Openings in thrust manifold (156)