Look at the electricity bill of a wastewater treatment plant and you will usually find that more than half of total consumption goes to aeration. Blowers run around the clock to supply the dissolved oxygen that micro-organisms need in the biological basin. A small gain in aeration efficiency therefore makes a serious difference to annual cost.
Why bubble size matters so much
Oxygen dissolution is proportional to the air-water contact area. Releasing the same volume of air as many small bubbles multiplies the total surface area compared with a few large ones. Small bubbles also rise more slowly, which extends contact time. Together these effects transfer markedly more oxygen at the same air flow.
Choosing a diffuser type
The two common options in fine bubble systems are plate and tube diffusers. Plate diffusers deliver higher transfer efficiency per unit area and give even distribution in wide, shallow basins when laid out as a grid. Tube diffusers are easier to install in narrow, deep tanks.
Operating conditions that decide membrane life
The service life of EPDM membranes depends largely on the cleanliness of the inlet air. Oil and dust carried by unfiltered air gradually block the perforations; pressure loss rises, the blower works harder and the savings evaporate. Regular filter maintenance is the cheapest measure protecting the return on a diffuser investment.
If you are evaluating an aeration upgrade at an existing plant, our commissioning and operational support service includes a measurement-based analysis.
