Wastewater first flows into the anaerobic filter tank where solid matter is separated from wastewater, which then flows into the contact aeration tank. The anaerobic filter tank is designed not only for storing the separated solid matter and sludge, but also for removing BOD and reducing the amount of sludge as the result of anaerobic digestion of anaerobic microorganisms attached to the filters.
In the contact aeration tank, degradation of organic matter and oxidation of ammonia proceed with the help of aerobic microorganisms fed by air from a blower. Aerobically treated water is separated from suspended solids in the sedimentation tank, and the supernatant water is discharged after disinfection by chlorine tablets.
