I am not sure if you mean Anaerobic Baffled Reactor (ABR).

The process in the ABR is anaerobic one and it must not be followed by the aerobic process.

Generally, the anaerobic processes in wastewater treatment are followed by aerobic one to increase the efficiency of wastewater treatment. The anaerobic processes have lower efficiency and the aerobic step serves as a polishing step, i.e. to remove rest concentration of COD, BOD, NH4, etc.

Best regards

Vit

Yes, as Final polishing unit (FPU).

Thanks sir