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Scum pit level control is similar to other well-level pumping. Typically, constant-speed pumps are used and there is a high “start-level” setpoint and a low “stop-level” setpoint. When the level reaches the start-level setpoint, the scum pump is started. When the level reaches the stop-level setpoint, the scum pump is stopped.

Scum tends to stratify in the scum pit, with the scum rising to the top and the water falling to the lower level. In some systems, the pit is mixed to allow a more homogeneous mixture, which will be easier to pump than the concentrated scum. In these instances, the mixer is started when the level reaches the “start pump” setpoint and is run for a time equal to a setpoint. When the mixer stops, the scum pump is started.