ENERGY SAVING USING JACKED AERATORS AT BIDDULPH SEWAGE-TREATMENT WORKS

A means of improving the energy efficiency of an existing mechanically aerated activated-sludge system by mounting the existing aeration units on jacked platforms is described. The level of the platforms, and hence the immersion of the aerators, is automatically controlled to maintain a constant concentration of dissolved oxygen in the mixed liquor. Comparison of the controlled stream, in which there were two aerators, against an otherwise identical control stream showed energy savings of 20% and 13% respectively when the control involved both or only one aerator, without adverse effect on final effluent quality.