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 tank, and is mixed with a first concentrated mixture to obtain a first mixture; (2) the first mixture is aerated in the aeration stage of the first aeration tank to obtain a second mixture at a second end of the first aeration tank; (3) the second mixture is introduced into a first sedimentation tank to obtain a supernatant and the first concentrated mixture; (4) the supernatant is discharged and at least a part of the first concentrated mixture is refluxed to the first end of the first aeration tank. At the same time, a sewage treatment method applying the pretreatment method is provided. The pretreatment method can be used steadily for a long time without discharging sludge.