| 摘要 |
PROBLEM TO BE SOLVED: To reduce an excessive usage of the neutralizer by the conventional biological treatment, a usage of an inorganic coagulant in a subsequent aggregation step and salt load in RO (reverse osmotic) membrane separation and ion exchange treatment, by efficiently performing neutralization in the biological treatment of an organic wastewater discharged from electronic device manufacturing processes.SOLUTION: When the organic wastewater discharged from the electronic device manufacturing process is passed through two or more biological treatment tanks containing at least 2 aerobic biological treatment tanks including an aerobic biological treatment tank at the last stage one by one to perform biological treatment to them, a neutralizer is added to the biological treatment tanks other than the final stage biological treatment tank so that M-alkalinity of the inner liquid of the final stage biological treatment tank may be maintained equal to or less than 50 mg/L as CaCO.SELECTED DRAWING: Figure 1 |
