Temperatures change. Do your blowers change with them?

February 2, 2022

According to historical records, we're just reaching the bitter end of the typical low point for annual temperatures. For most of Nebraska and South Dakota, the average coldest day of the year is between January 16th and January 20th, and for almost all of Iowa, it's between January 21st and January 25th. From this point forward, the days will mostly be growing warmer. Temperature has a big impact on wastewater aeration: Colder air is denser air, and colder water holds more dissolved oxygen than warm water. Thus, the demand for aeration is generally lowest right about now -- and will increase as both air and water grow warmer moving towards the middle of the year. The difference in horsepower required to achieve the same DO levels in treated wastewater can be substantially less in the winter than in the summer, and with thoughtful application and good control systems, engineers can design systems that give operators (and utility owners) significant electrical savings by adjusting to those temperature swings. Every unit of horsepower counts: At 10 cents per kilowatt-hour, dropping aeration demand by just 10 hp for six months out of the year could save well over $3,000. Switching to VFD-controlled high-efficiency centrifugal blowers can have a fast payback period, especially when other financial resources like grants and low-interest loans for energy efficiency are available. Check out our presentation on blower throttling for more details and contact us for more information on free energy audits and technical application assistance.