 Increased mechanical
efficiency in blower components, and dynamic load-following control strategies
present an opportunity for significant energy savings in wastewater treatment.
Approximately 30-60 percent of the energy used to treat wastewater is
used to power blowers or other aeration equipment in the secondary treatment
process. The CEE Municipal Water-Wastewater Committee has invited leading blower manufacturers to the Industry Partners Meeting to address the lack of a consistent energy performance metric for blowers. More consistent metrics could generate opportunities to mutually benefit manufacturers and efficiency program administrators, and that could streamline the path to mass market programs for blower systems. The outcomes of this work could provide efficiency programs with access to large-scale energy savings at more than 16,000 wastewater treatment facilities located in virtually every city and town in North America
Building on prior efforts to demonstrate the ENERGY STAR
Portfolio Manager benchmarking tool and to develop guidelines for incorporating
energy efficiency into municipal requests for qualifications and proposals
(RFQs and RFPs), the Water-Wastewater Committee is focused on identifying
opportunities for programs to take advantage of energy savings resulting
from advances in aeration technology.
CEE Committee members were informed of this opportunity through outreach
to technical consultants and blower manufacturers. In May, the Committee
held a call with engineering consultants David Michelsen and Mike
Wilson—of SEA Consultants and CH2M Hill, respectively—to learn more about next-generation high-speed blower technologies. High-speed blowers emerged in the North American market around 2007, and came to the attention of CEE committee members because of manufacturer claims that these new units offer a significant efficiency premium (15 percent is a common figure) when compared to “traditional” blower
equipment.
High-speed blowers use advanced motor and bearing technologies to
achieve mechanical efficiency gains. They also include a dynamic control
package—integrated
variable speed drive, sensor, and controls—that automatically adjusts
blower speed to correspond to load (typically bio organic oxygen demand)
in real time.
During those meetings, the Committee learned that the blowers industry does not use a consistent energy performance metric or test procedure. Metrics and test procedures vary by blower type, for example, positive displacement, high-speed, or between manufacturers. A question also emerged as to how much of the energy performance improvement claimed by high-speed units is attributable to their improved mechanical efficiency, and how much to their dynamic control capability.
CEE members plan to work collaboratively with blower manufacturers
at the Industry Partners Meeting and afterward, to pursue consistent
energy performance metrics for blowers and guidance on aeration system
control strategies. For more information on this effort or the CEE Water-Wastewater
Committee, contact Jess Burgess at 617-337-9274, or by email at jburgess
at cee1.org. |
