The SBR system accomplishes equalization, biological treatment and settling in a timed sequence. A sequence consists of five main phases: 1)Fill 2) React ) Settle 4) Decant 5) Idle. These main phases can be divided further into sub phases depending on the treatment. The result is a very simple and flexible system that can be adapted to the specific conditions. In the system the reaction tank is filled with raw wastewater. During the fill phase and the subsequent react phase, the wastewater is treated biologically. The reaction tank can perform both nitrification and de-nitrification which means that the plant can offer the needed conditions where the water is instead of pumping the water to another tank with the right conditions. As a result, the need for an internal recirculation is eliminated. After the biological treatment a settling phase is initiated. As the system includes internal sedimentation, the need for an external clarifier with recirculation of sludge is also eliminated. After sedimentation the treated water is discharged from the system before new wastewater is admitted. As it is seen the water volume in a SBR system varies during a sequence.
Advantages of Sequencing Batch Reactor
- Operating flexibility and control.
- Potential capital cost savings by eliminating clarifiers and other equipment
- Equalization, primary clarification (in most cases), biological treatment, and secondary clarification can be achieved in a single reactor vessel
- Minimal footprint.