Abstract: A process for high-load treatment of carbohydrate-containing waste water comprises the steps of separating a yeast appearing in the waste water, subjecting the separated yeast to large-quantity culture, and treating the waste water by a high-load operation using the cultured yeast as a seed fungus under the conditions of a volume load of 10 to 80 kg-BOD/m.sup.3 .multidot.day and a yeast load of 1.0 to 5.0 kg-BOD/kg-yeast.multidot.day, whereby it is possible to treat the high-concentration waste water efficiently with a small volume for treatment. To obviate the conflict between the yeast and bacteria, it is recommendable to add Cl.sub.2 to a reservoir in an amount of 10 to 50 mg/l. Upon the treatment of the waste water, a surplus of yeast is generated, which contains proteins and vitamins in high contents and, therefore, is capable of being taken by a fodder company as fodder or fertilizer; thus, the disposal cost associated with the surplus yeast is saved.