Aeration Blowers - they are not all equal

Aeration of the activated sludge process in a typical suspended growth wastewater treatment facility can consume anywhere from 40 to 70 percent of the power consumed by the total plant. Because such a large fraction of the overall plant power is consumed by the aeration blowers, it is important to select the blower system on best value. So how does one identify best value? With a minimum of 16 different blower manufacturers, how does one sift through the sixteen different sets of manufacturers’ information to provide a comprehensive and defensible result?

For activated sludge aeration, there are currently three different blower technologies that are economically applicable: multi-stage, gear-driven single-stage, and direct-drive single-stage centrifugals. Many recent papers have discussed various blower technologies, mainly focusing on the newer direct-drive technology, which exploded onto the marketplace approximately five years ago, with each different manufacturer telling different stories about their efficiency and applicability. Few papers have provided side-by-side comparison of the predicted power consumption of the various blower configurations.

Historically, blower performance and selection has been specified on a few theoretical performance points. A more realistic approach is required to match realistic airflow rates with realistic relative humidity and inlet air temperatures. A much larger set of data points than 4-5 is required to realistically describe the daily airflow requirements throughout the year, and hence develop a more realistic picture of power consumption throughout the year.

Aeration blower types and manufacturers are discussed. An evaluation procedure is outlines and results from the analysis of the manufacturers’ proposals are discussed.