Air Technology Limited were contracted to identify potential high-power use sites and identified this site as being particularly poor. The site consisted of primary settlement followed by an Activated Sludge Plant, which comprised of a four-cell aeration tank with cells or pockets arranged in series, aerated by 12 off 21kW submersible jet aerators. These were chosen due to noise concerns from nearby customers.

Air Technology were asked to complete a full aeration survey, involving DO surveys, pollutant abatement mapping and power measurements. This survey identified that treatment was poor, with low DO levels throughout the aeration tank despite the power consumption being exceptionally high. The poor treatment and low DO levels resulted in high levels of foaming on the tank surface as can be seen above and was resulting in poor settlement in the Final Settlement Tanks. Air Technology’s report recommended replacement of the jet aerators with fine bubble diffused aeration and blowers housed in acoustic enclosures. This would save over £120,000/annum on energy alone, with maintenance savings of over £30,000/annum.

This would save over £120,000/annum on energy alone, with maintenance savings of over £30,000/annum.

The installation was managed by a Framework Partner, with the design and specification provided by Air Technology Limited who also designed and carried out the control system upgrade and commissioned the system.

The improvements were immediate, with much reduced levels of moussing and a vast improvement in FE quality, especially solids carryover from the FST’s which has saved over £1million in predicted cleaning costs for the sites lagoon.

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