Method of and apparatus for the mechanical-biological treatment of sewage

Claim 1

A mechanical-biological sewage treatment plant for the purification of sewage includes a settling tank having a water level therein, an immersion element located within said tank and extending below the water level in said tank, said immersion element having a horizontally extending central axis and including a perforated axially elongated outer tube concentrically arranged about the central axis and said outer tube having opposite ends extending transversely of the central axis, support elements for biological growth located within said outer tube, an inner tube located concentrically about the central axis within and spaced radially inwardly from said outer tube and being almost completely submerged below this water level, said inner tube having opposite ends extending transversely of the central axis, means located within said tank for rotatably supporting said immersion element about the central axis, means for forming a closure extending across the opposite ends of said inner and outer tubes, the outer surface of said outer tube having outwardly extending projections for forming an intensely turbulent sewage air mixture as said immersion element rotates for introducing oxygen into the mixture, said support elements having an outside surface and multiple inside surfaces in spaced relation located inwardly from said outside surface, said support elements being movable relative to one another and to said inner and outer tubes, said inside surfaces having a large surface area and said outside surface having multiple openings therethrough leading to said inside surfaces so that the sewage-air mixture flows through the openings and over the inside surfaces.

Claim 21

A method of mechanical-biological treatment of sewage in a settling tank containing a water level, a rotatable immersion element supported in the settling tank and extending below the water level with the immersion element including an outer tube and an inner tube spaced radially inwardly from the outer tube and defining a closed space therebetween, including the steps of forming the outer surface of the outer tube with outwardly extending projections so that the projections extend above the water level during rotation of the immersion element, rotating the immersion element about a horizontal central axis for drawing air into and mixing it with sewage, and rotating the immersion element so that the rotational speed at the circumferential periphery of the outer tube is such that an intensely turbulent and thoroughly mixed sewage-air mixture results, providing support elements movable relative to the inner and outer tubes and on which biological growth collects in the space between the inner and outer tube, and flowing the sewage-air mixture through the interior of support elements in contact with the biological growth for effecting the treatment of the sewage.

Claim 22

A method of mechanical-biological treatment of sewage in a settling tank containing a water level, a rotatable immersion element supported in the settling tank and extending below the water level with the immersion element including an outer tube and an inner tube spaced radially inwardly from the outer tube and defining a closed space therebetween, including the steps of forming the outer surface of the outer tube with outwardly extending projections so that the projections extend above the water level during rotation of the immersion element, rotating the immersion element about a horizontal central axis for drawing air into and mixing it with sewage, and rotating the immersion element so that the rotational speed at the circumferential periphery of the outer tube is such that an intensely turbulent and thoroughly mixed sewage-air mixture results, providing support elements movable relative to the inner and outer tubes and on which biological growth collects in the space between the inner and outer tube, and flowing the sewage-air mixture through the interior of support elements in contact with the biological growth for effecting the treatment of the sewage.