PROCESS FOR HIGH-LOAD TREATMENT OF CARBOHYDRATE-CONTAINING WASTE WATER

摘要

(1) 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/m3 a yeast load of 1.0 to 5.0 kg-BOD/kg-yeast is possible to treat the high-concentration waste water efficiently with a small volume for treatment. The quantity of air required of a diffuser system blower may be 0.15 to 0.60 kg-O2/kg-BOD-removed, the value being 1/3 to 2/3 times that in a general activated sludge method. A pH of not more than 5.0 and a residence time of at least 1.5 hours may be employed. To obviate the conflict between the yeast and bacteria, it is recommendable to add C?2 to a reservoir in an amount of 10 to 50 mg/?. If it is impossible to add C?2 to the reservoir, the C?2 may be added to a yeast tank in the same amount as abovementioned. This process, when carried out under the conditions mentioned above, promises an increase in the efficiency of the plant for treatment of the carbohydratecontaining waste water. Upon the treatment of the waste water, a surplus of yeast is generated, which contains (2) proteins and vitamines 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. On the other hand, an about 20% portion of the influent BOD, which is left upon the treatment with yeast, requires an after-treatment, so that an expense is necessary for disposal of the sludge formed. The disposal cost required in this case, however, is as low as about 1/4 times that required in the general activated sludge method, and the disposal cost for the after-treated sludge is substantially negligible because it can be canceled by selling the surplus yeast as fodder or fertilizer, as mentioned above. Thus, the process for high-load treatment of carbohydrate-containing waste water promises a marked reduction in the treatment cost for the waste water.