WASTEWATER TREATMENT METHOD

摘要

PROBLEM TO BE SOLVED: To provide a wastewater treatment method having reduced amount of generated undesirable gas.SOLUTION: While the inside of a treatment tank 11 arranged with a carrier 11A is set to an oxygen atmosphere filled with high concentration oxygen 13A, treated water 14A obtained by purifying at least part of a material to be oxidized in wastewater 12A by a microorganism group carried on the carrier 11A is discharged outside. At this time, a state where water travels on at least either the surface or the inside of the carrier 11A and flows down is always maintained by alternately repeating a purification period for supplying the wastewater 12A and a starvation period for supplying purified water 15A having a lower concentration of the material to be oxidized than that of the wastewater 12A (low material-to-be-oxidized concentration water).