In common with most other waste water treatment plants world-wide, this treatment includes an ‘active sludge’ process. Essentially this process uses microbes to feed on the effluent and thus enable a further process to separate out clean water. In order for these microbes to live they demand large volumes of oxygen which has to be added to the effluent via an aeration process.

Aeration generally consumes large quantities of energy and accounts for around 60% of the operating cost of a treatment plant. The Newton Gravity Aerator was introduced to United Utilities with the projection of significantly reducing energy and maintenance costs.

United Utilities decided to undertake a feasibility test of the aerator at their Ellesmere Port R & D facility. The feasibility trial was awarded a SMART grant by the DTI.

The trial took effluent from their normal feed into a test tank in which a trial aerator was installed. The test tank had a capacity of 2 cu m. A trial aerator was designed to aerate this small tank and had a throughput of around 1 l/s.

United Utilities measured oxygen transfer of this aerator using industry standard methods, calculating KLa and kgO2/kWHr.The result of this test was the Newton Aerator consumed around 50% of the energy of comparable aerators in the test tank. With an inefficient small pump, the aerator’s efficiency was calculated to be 1.6 kgO2/kWHr.

Initial projections are that the Newton Aerator will save United Utilities in the region of £50,000 per annum per lane. Reduced maintenance costs need to be added to this figure. The final assessment is expected by Spring 2005.

Disused Minewater treatment Case Study >>