PROBLEM TO BE SOLVED: To provide a water treatment system that can sufficiently perform nitrification reaction without using a carrier holding nitrification bacterium.SOLUTION: The water treatment system 1 includes a circulation pipe 10 of which a water inlet 11 and a drainage outlet 12 are connected to a breeding aquarium 20. The circulation pipe 10 does not have a carrier holding nitrification bacterium inside the circulation pipe 10 and includes an oxygen gas supply device.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2018,JPO&INPIT【課題】硝化菌を保持した担体を用いることなく、十分に硝化反応が行える水処理システムを提供する。【解決手段】取水口11と排水口12とが飼育水槽20に接続された循環配管10を有し、循環配管10中に硝化菌を保持した担体を有さず、循環配管10が酸素ガス供給装置を備える水処理システム1。【選択図】図1
