Biological rotating cage reactor for water treatment and phosphorus-containing low-ammonia-nitrogen wastewater treatment method

The invention discloses a biological rotating cage reactor for water treatment, and the cage reactor comprises a reaction tank; a rotating cage rotating shaft is arranged on the reaction tank in the length direction of the reaction tank, a biological rotating cage is sleeved on the rotating cage rotating shaft, the biological rotating cage comprises a hollow disc-shaped disc body, the side wall ofthe hollow disc-shaped disc body is provided with a filler feeding hole, and the filler feeding hole is communicated with the hollow disc-shaped disc body; a cover plate is arranged on the feeding hole, a filler is arranged in the hollow disc-shaped disc body, and a plurality of water permeable holes are evenly distributed in the two side faces of the hollow disc-shaped disc body. According to the invention, the filler is filled in the biological rotating cage, and films can be formed on the filler and the disc, so the specific surface area and the film forming amount of the biological rotating cage can be increased,