Infrastructure spending in the United States has not kept pace with the population growth and many wastewater treatment plants are at peak capacity. The nation's wastewater systems and their ratepayers face a major challenge in funding the expansion, replacement, and maintenance of aging infrastructure over the next several decades. For this reason, plant engineers and operators have significantly increased the focus on lifecycle costs including initial price, installation, maintenance and energy costs. Additionally, new regulations require the reducing nutrients in the effluent discharged from existing plants.
One method to meet these challenges is simply to increase the size of the wastewater treatment plant. Another way is integrating processes such as supplemental biological contactors by incorporating subsurface aeration equipment into existing plant operations. This second means presents the added benefit of increasing plant capacity without requiring plant expansion.
Common to both methods, is the need for an increased oxygen supply to support the process. Blowers have become the most common and most efficient method to introduce oxygen to aerobic digesters. Blowers can replace expensive liquid oxygen injection systems and inefficient mechanical surface splashers. Among blowers, there are two common options: centrifugal blowers and positive displacement rotary-lobe blowers.