NOVELTY - A cycle closed type filler-free high-efficiency ammonia nitrogen removing and nutrient recovery device has an air stripping tower and an absorption device. The air stripping tower includes a tower top, a tower body and a tower bottom. The air stripping tower is connected with a circulating pump, an automatic alkaline agent feeding device, an ozone generator, a sample tap and an exhaust port. The absorption device includes an alkali absorption pot and primary and secondary acid absorption pots that are connected with each other through pipelines.    USE - Cycle closed type filler-free high-efficiency ammonia nitrogen removing and nutrient recovery device for post-processing of raw material biogas slurries.    ADVANTAGE - The device has simple structure and treatment process, low cost, stable performance, good purifying effect, simple operation and management, and is easy to maintain.    DETAILED DESCRIPTION - A cycle closed type filler-free high-efficiency ammonia nitrogen removing and nutrient recovery device has an air stripping tower and an absorption device. The air stripping tower includes a tower top, a tower body and a tower bottom. The air stripping tower is connected with a circulating pump, an automatic alkaline agent feeding device, an ozone generator, a sample tap and an exhaust port. The absorption device includes an alkali absorption pot and primary and secondary acid absorption pots that are connected with each other through pipelines. The tower top is provided with an extraction opening and the upper portion of the tower body is provided with a demister and a baffle plate. The upper portion of the tower body is equipped with a liquid inlet tube, an alkaline agent feed inlet and a gas distribution device. The lower portion of the tower body is provided with a biogas slurry circulation port and a drain outlet. The tower bottom is provided with an air inlet and an alkaline agent catch basin. An aeration self-stirring device is connected with an air inlet pipe through a bearing and a sealing member. The aeration self-stirring device rotates under the backward thrust of air impact on water.