Aeration of wastewater for the activated sludge process can be achieved by fine bubble diffusers, or by mechanical aerators. Fine bubble systems are most efficient at water depth in excess of 4m, and mechanical systems are more economical for shallow depths or small installations. The efficiencies in actual conditions as compared to clean water, blur the differences, as mechanical devices can offer a better alpha factor- the numerical indicator of actual biological performance.
The mechanical aerator type is also better suited to aerobic digestion, as it provides vigorous mixing together with higher oxygen transfer efficiency in real (high consistency mixed liquor) operating conditions.
Magytec international Pty Ltd customers include John Young (Kelvinhaugh) Pty Ltd (Now Abergeldie Young Process Engineering) who offer complete aeration systems including Fine bubble diffusers, submersible mixer/aerators, and surface mechanical aerators.
Some of the many Australian aeration installations we have been associated with include:
If there is a possibility of multiple parallel aeration basins, fixed diffuser grids are usually much more practical. The ultimate liftable system is the submerged turbine mixer/aerator, which offers high alpha factors, no fouling, and total flexibility. In this paper we discuss why this is so.
Off site testing can be more accurate, particularly for large projects. We discuss the practical difficulties of achieving an accurate result.
The alpha factor is a measure of the Actual Oxygen transfer when aerating in real conditions with the biosolids, as compared to clean water testing. In this article we describe how the alpha factor can be tested, and this information put to use on a tough industrial wastewater aeration application of a submerged turbine aerator.