1. Filling phase

The reactor receives sewage water from the intake tank/surge drum. The filling phase will vary time-wise depending on the system's hydraulic load and pulse aeration of the reactor will take place throughout this phase to maintain a good biology. The filling phase can take place with one or more pumpings.

2. Reactor phase

The reactor is aerated continuously to add oxygen to the biology which again breaks down and uses nutrients. The length of this phase will depend on the composition of the sewage water – high concentrations require longer aeration times while lower inflow concentrations require shorter aeration times. If phosphorus needs to be removed, chemicals are added in this phase.

3. Sedimentation phase

The blower fan is stopped and all valves are closed to achieve calm and stable sedimentation conditions. This gives low concentrations of suspended material in the treated sewage water.

4. Sludge removal

During the sedimentation phase excess sludge is removed through the sludge valve and drained away for storage or further treatment. In storage, the sludge is thickened further using gravitation. The phosphorus has now gone from water phase to sludge phase and has therefore been removed from the treated sewage water.

5. Delivery phase

The treated sewage water is drained to a suitable receptacle through the delivery valve.

The reactor will then go to a waiting phase where it will pulse aerate while waiting for a new batch of sewage water.