Rotating disk type sewage treatment device

Rotating biological contactor-type sewage treatment equipment which comprises a treatment tank for storing sewage to be treated, a rotation shaft which extends across opposed side walls of the treatment tank, a plurality of rotating discs mounted at a predetermined interval on the rotation shaft in such a manner that each rotating disc is partly submerged in the sewage stored in the treatment tank, and a driving means for supplying a driving force to the rotation shaft in order to rotate the rotating discs,

• the sewage treatment equipment treating sewage by rotating the rotating discs on which aerobic bacteria are attached, thereby allowing the aerobic bacteria to contact the sewage and aerobically decompose pollutants in the sewage,
• wherein the sewage treatment equipment is characterized in:
• that each of the rotating discs is composed of n portions of sector-shaped segments, wherein n is an integer not less than 1, each of the sector-shaped segments being composed of two equally divided sector-shaped pieces and each of the sector-shaped pieces having thin elements which form meshes;
• that the meshes have the same size and shape except in the neighborhood of a periphery surrounding the each sector-shaped piece, and an arrangement of the meshes is regularly aligned in the same direction relative to one side of the each sector-shaped piece;
• that projections project from predetermined locations on the thin elements and extend perpendicularly relative to each surface of each rotating disc;
• and
• that, in an installation state where adjacent rotating discs are displaced from each other by 360°/2n in a direction of rotation, projections which locate on one of the adjacent rotating discs are oriented to openings in the meshes formed by the thin elements of another rotating disc.