When the HRT of two-stage biological contact oxidation is ten hours, the CODcr removal can reach 87.6%, and the last effluent CODcr can decline bellow 100 mg/L, meeting the first-level discharged criteria in GB8978.

• 当二段生物接触氧化法水力停留时间 10h时 ,CODcr去除率达 87 6%25 ,最终出水CODcr降至 10 0mg/L以下 ,达到GB8978一级排放标准。