A filter sector assembly for a disc filter, which disc filter has a fiber suspension containing bath and a core assembly adapted to rotate on a horizontal axis. The filter sector assemblies are rotatably supported with relation to the bath on the core assembly. The filter sector assemblies are spaced along the core assembly and supported on the core assembly. Each filter sector assembly (50) has two adjacent filter sectors (10A; 10B) releasably fixed to a bent support plate (30). The two adjacent filter sectors (10A; 10B) are attached as a pair of filter sectors (10A; 10B) by fastening the support plate (30) to the core assembly (21; 21A, 21B) of the disc filter.

A ceramic filter plate (22) is provided with a conductive wiring (70, 71) extending along the filter plate to form a continuous electrical circuit and arranged to break upon breakage of the filter plate. The integrity of the conductive wiring (70, 71) is monitored, and the operation, particularly the rotation, of the disc filter is immediately stopped upon detecting a break of the conductive wiring.

A ceramic filter plate (22) is provided with a conductive wiring (70, 71) extending along the filter plate to form a continuous electrical circuit and arranged to break upon breakage of the filter plate. The integrity of the conductive wiring (70, 71) is monitored, and the operation, particularly the rotation, of the disc filter is immediately stopped upon detecting a break of the conductive wiring.

A filter element for use in a filter disc, wherein a plurality of filter elements are arranged on a rotor shaft in a manner allowing liquid communication between the inside of the filter elements and the inside of the rotor shaft. The filter element has at least one passage in an edge structure for liquid communication between the inside of adjacent filter elements when the filter elements are assembled forming a filter disc. The passage has different passage area along the edge structure.

A rotary disk filter includes a drum and filter disks. Each filter disk has an inner hollow space, at least a portion of which is delimited by filter surfaces, wherein the hollow spaces are fluidically connected to the drum such that the waste water can flow from the interior of the drum into the hollow spaces and, from there, the filtrate can flow across the filter surfaces toward the outside. The rotary disk filter also has a spray nozzle arrangement including spray nozzle tubes and spray nozzles mounted on the spray nozzle tubes. In one aspect, the spray nozzles each have two spray nozzle sections (each having at least one nozzle head), and an interlocking connection, by means of which the spray nozzle sections are connected to the spray nozzle tubes. The spray nozzles can be removed from the spray nozzle tube once the interlocking connection has been released.

A rotary disk filter includes a drum and filter disks. Each filter disk has an inner hollow space, at least a portion of which is delimited by filter surfaces, wherein the hollow spaces are fluidically connected to the drum such that the waste water can flow from the interior of the drum into the hollow spaces and, from there, the filtrate can flow across the filter surfaces toward the outside. The rotary disk filter also has a spray nozzle arrangement including spray nozzle tubes and spray nozzles mounted on the spray nozzle tubes. In one aspect, the spray nozzles each have two spray nozzle sections (each having at least one nozzle head), and an interlocking connection, by means of which the spray nozzle sections are connected to the spray nozzle tubes. The spray nozzles can be removed from the spray nozzle tube once the interlocking connection has been released.

An industrialized fish and algae farming system with recirculating water and method are provided, and the system includes a fish and algae farming system, a fiber rotary disc filter system, and a magnetic loading flocculation system. In accordance with the fish and algae farming system, the aquaculture of fish and algae in the same space is achieved, the algae can transform CO.sub.2 exhaled by fish and nutrients, polysaccharides, vitamins and lipids, and then release oxygen to rapidly improve the aquaculture water quality. The fiber rotary disc filter system and the magnetic loading flocculation system can effectively remove suspended particles, grease, algae, bacteria, viruses and the like in aquaculture sewage, thus achieving the deep purification of the aquaculture sewage. The purified water quality reaches the aquaculture standards in fishery and can be directly recycled, and the whole system has no sewage discharge.

An industrialized fish and algae farming system with recirculating water and method are provided, and the system includes a fish and algae farming system, a fiber rotary disc filter system, and a magnetic loading flocculation system. In accordance with the fish and algae farming system, the aquaculture of fish and algae in the same space is achieved, the algae can transform CO.sub.2 exhaled by fish and nutrients, polysaccharides, vitamins and lipids, and then release oxygen to rapidly improve the aquaculture water quality. The fiber rotary disc filter system and the magnetic loading flocculation system can effectively remove suspended particles, grease, algae, bacteria, viruses and the like in aquaculture sewage, thus achieving the deep purification of the aquaculture sewage. The purified water quality reaches the aquaculture standards in fishery and can be directly recycled, and the whole system has no sewage discharge.

A filter for filtering a flow of liquid a filter assembly with a number of filter disks coaxially arrayed along a central flow path within a pressure vessel. Each filter disk has a number of segments. The segments are preferably implemented as spacers with outward-facing filler screen support configurations supporting first and second filter screens. The filter screen support configurations have a cellular form that is open over a majority of a surface area, An arrangement of support ribs are deployed to maintain a spacing between the first and second filter screen support configurations. At least 80 percent of an internal volume of each of the segments is preferably open to allow liquid flow from the screens to the central flow path. Also disclosed are modular structure's of the filter disks, and a backwash arrangement which performs a spiral scanning motion across the surface of each filter disk.

A filter for filtering a flow of liquid a filter assembly with a number of filter disks coaxially arrayed along a central flow path within a pressure vessel. Each filter disk has a number of segments. The segments are preferably implemented as spacers with outward-facing filler screen support configurations supporting first and second filter screens. The filter screen support configurations have a cellular form that is open over a majority of a surface area, An arrangement of support ribs are deployed to maintain a spacing between the first and second filter screen support configurations. At least 80 percent of an internal volume of each of the segments is preferably open to allow liquid flow from the screens to the central flow path. Also disclosed are modular structure's of the filter disks, and a backwash arrangement which performs a spiral scanning motion across the surface of each filter disk.