By Stephen Horne, Kaeser Compressors, Inc.
Energy is the single highest operating cost in a wastewater treatment plant. More specifically, the energy to operate blowers for aeration is the single highest energy consumer. Fortunately, blowers and blower systems are becoming more energy efficient as system engineers pay more attention to this critical cost factor. It is no longer enough to only consider the individual equipment’s efficiency. With energy costs on the rise, it is now more important than ever to carefully examine the entire system’s efficiency and understand how each piece of equipment works with one another and how this interaction impacts the overall plant energy efficiency. This paper will outline the traditional approach to wastewater treatment plant design, the efficiency problems associated with this approach, and explain system splitting, an alternate design approach with key efficiency gains. The paper will include guidance on how to calculate specific power for an individual unit as well as an entire system and provide calculation examples for comparing system specific power between traditional and system splitting design approaches.