EMC-compliant drives are used to clean up the sludge

Direct Torque Control (DTC) is being used to operate the 22kW a.c. drives used at the Lesmahagow treatment works in Lanarkshire. The EMC-compliant drives adjust oxygen input into the sewage by controlling the speed of the aerator’s impeller. A reliable drive is essential, as failure of the impeller can lead to bacteria dying and the […]

Direct Torque Control (DTC) is being used to operate the 22kW a.c. drives used at the Lesmahagow treatment works in Lanarkshire. The EMC-compliant drives adjust oxygen input into the sewage by controlling the speed of the aerator’s impeller.

A reliable drive is essential, as failure of the impeller can lead to bacteria dying and the resulting effluent going outside a BOD level of 20 mg/l.

Before installing the drive, the vertical shaft aerators ran at full speed and the aeration rate was varied by adjusting the level in the tank, which changed the amount of turbulence.

This approach was energy intensive and often in the past did not provide a sufficient level of control to comply with all environmental regulations.

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