Method for forming aerobic granules, device for forming aerobic granules, method for treating wastewater, and device for treating wastewater

A device for forming aerobic granules comprising a semibatch reactor that forms granules by repeatedly performing an introduction introducing an organic matter-containing wastewater containing organic matter, a biological treatment biologically treating treatment target substances in the organic matter-containing wastewater using a microbial sludge, a settling allowing the microbial sludge to settle, and a discharge discharging a biologically treated water that has been biologically treated and

• a control device that controls a reaction time of the biological treatment in the semibatch reactor and sludge withdrawal, wherein
• the control device is programmed to adjust the reaction time of the biological treatment so that a value obtained by multiplying a ratio of an MLSS concentration relative to a BOD load introduced into the semibatch reactor by [total cycle time/reaction time] falls within a range from 0.05 to 0.25 kgBOD/kgMLSS/d, and the sludge is withdrawn such that a sludge retention time is 5 to 25 days.