Over the past 3 years, Billings upgraded their wastewater treatment process to produce even higher quality water that returns to the Yellowstone River. Part of this $75 million upgrade included constructing a state-of-the-art aeration system that maximizes energy efficiency. Aeration is the most energy intensive process required in wastewater treatment, accounting for approximately half of
the electrical load used.
NorthWestern Energy awarded the City of Billings $90,000 in E+Business Partners
Energy Efficiency incentives for the installation of energy efficient equipment during thei
recent construction project. The Billings aeration system upgrades are estimated to
save about 743,000 kilowatt-hours (kWh) per year, resulting in about $57,300 in annual
electric cost savings based on today’s electric costs.
The aeration system uses turbo blowers, much like a turbo charger in a sports car, that
rotate at speeds of over 30,000 rpm. These high speeds allow the rotating shaft to
literally levitate in air creating very little friction resistance. This results in lower energy
requirements. Additionally, a new automated control system that incorporates a most
open valve (MOV) technology was installed. The new control system interfaces with the
dissolved oxygen (DO) probes located in the aeration tanks to control the inlet valves
serving each basin. The control system functions to operate the blower/aeration system
at the minimum possible pressure by operating in a “most open valve” condition. All this
means less energy required to produce high quality water for the Yellowstone River.
The project was initiated by a team composed of City of Billings staff, NorthWestern
Energy representatives and consultants working together to identify energy savings
opportunities for the City of Billings.
During the last 10 years, the City of Billings implemented 62 energy efficiency projects;
qualifying for $967,050 in energy efficiency incentives from NorthWestern Energy.
These projects resulted in an estimated 5.82 million kWhs saved per year, equating to
about $455,000 in annual electric cost savings.
In addition, the City of Billings has received $612,257 in Large Customer Universal
Systems Benefit funding for 14 energy efficiency projects. These projects resulted in an
estimated 1.37 million kWhs saved per year, equating to about $104,500 in annual
electric cost savings.