WASTEWATER PRETREATMENT METHOD AND SEWAGE TREATMENT METHOD USING THE PRETREATMENT METHOD

摘要

A pretreatment method is provided, which comprises the following steps: (1) wastewater feed is introduced into a first end of a first aeration basin, and is mixed with a first concentrated mixed liquor to obtain a first mixed liquor; (2) the first mixed liquor is aerated in the aeration stage of the first aeration basin to obtain a second mixed liquor at a second end of the first aeration basin; (3) the second mixed liquor is introduced into a first sedimentation basin to obtain a supernatant and the first concentrated mixed liquor; (4) the supernatant is discharged and at least a part of the first concentrated mixed liquor is returned to the first end of the first aeration basin. At the same time, a sewage treatment method using the wastewater pretreatment method is provided. The pretreatment method can be used steadily for a long time without discharging sludge.