- ASR designed to operate in transient state, commonly consist of ≥ 2 basins that operate in parallel
- Ability to treat a wide range of influent volumes
- Fill and draw principle, involve procedures such as:
- Filling
- Mixing
- Reaction
- Clarification
- Decanting
- Produce sludge with good settling properties if aeration was well controlled
- Treated water is suitable to be discharged to surface waters