The City of New Ulm achieved $98,000 in energy savings in one year after the installation of new aeration blower motors, variable speed drives, controls, and air distribution system in their Waste Water Treatment Plant. After the first year of measurement it is projected that the upgrades will have a 5 year payback.
Two years ago, two new 300 horse power aeration blower motors were installed to replace the existing 900 horse power motors. Variable speed drives were installed along with the motors, and as a result the motors run between 60-80% capacity when needed, as opposed to running at 100% capacity all of the time.
Controls were also installed to monitor dissolved oxygen levels and an air diffuser system to more efficiently digest solids. Now oxygen levels are known in real time so the motors are able to adjust their speed to efficiently operate the plant.
Besides energy savings, these upgrades allow the Waste Water Treatment Plant to operate better, and therefore further limit future chemical treatments of the facility. Chemical treatments were not a common occurrence at the facility; however, to further limit the possibility of this expensive process is beneficial for the community.
At a glance:
- Projects: Aeration Blower Motors, Variable Speed Drives, Controls, and Air Distribution System
- First year cost savings: $98,000
- Projected payback: 5 years
About the Local Government Energy Action Series:
This year-long effort tells the stories of nearly 50 Minnesota municipalities, counties, and schools and the tangible results of their energy-saving efforts to inspire others to take their own actions.
Local Government Energy Action is brought to you by the Clean Energy Resource Teams (CERTs) in partnership with the Minnesota Department of Commerce, Division of Energy Resource
