PROBLEM TO BE SOLVED: To provide a water treatment method that can purify water in a growth tank stably and efficiently, and a water treatment apparatus. SOLUTION: The water treatment method includes: a step (I) of discharging organic matters, contained in treated water introduced from the growth tank 1, upward from a protein skimmer 2 to eliminate, using microbubbles generated by a microbubble generating means 4 arranged in a lower part of the protein skimmer 2, in the protein skimmer 2; a step (II) of making the microbubbles in the treated water that has passed the protein skimmer 2 micro-nanobubbles and/or nanobubbles; and a step (III) of bringing the treated water containing the micro-nanobubbles and/or nanobubbles obtained by the step (II) into contact with an enzyme agent containing Bacillus subtilis or Bacillus subtilis and an organic decomposition enzyme in an aerobic microorganism treatment tank 3. The water treatment apparatus suitable for conducting the method is also provided. COPYRIGHT: (C)2012,JPO&INPIT
