Surface aeration versus other aeration systems

Until the introduction of the fine bubble aeration, the alpha factor was hardly known, because this factor of 0.93 had always been neglected with surface aeration. Later on, this comparison factor between pure water and sewage water became an increasing problem for the fine bubble aeration process. Initially it was calculated with an alpha factor of 0.80 for bubble aeration, but a value of 0.65, which can dramatically fluctuate, quickly became a standard in the literature. Because most pressure elements lose 2 – 3 % per year of effectiveness, most offices calculate today using an alpha factor between 0.50 until 0.60. In the chart below a mathematical comparison illustrates the influence of aging and the alpha factor:

O2-efficiency Clean water [kg O2/kWh] Alpha- factor O2-efficiency Waste water [kg O2/kWh] after 10 years
Brush and old type vertical shaft aerator 1.60 0.90 1.44 1.43
Bubble aerator 4.00 0.60 2.40 1.96
High efficiency Surface Aerator O2Max 2.40 0.90 2.16 2.16

This comparison considers experienced values of a basin with a depth of approximately 4.5 metres. In more shallow basins, the economical advantage of the Surface Aerator in comparison with fine bubble aeration is becoming rapidly higher.

Advantages of O2Max vs. other aeration systems:

  • Extremely reliable
  • High aeration efficiency (>20% increased)
  • Non clogging
  • Low maintenance costs
  • Low vibrations
  • Low upthrust and radial force
  • Low investment costs
  • Long lifetime
  • No problems in adhesive or DS containing sludge (pulp and paper industry, breweries, dairies, sludge digestion/stabilization etc.)