Moundsville Uses Variable Frequency Drives to Improve Aeration Control and Lower Costs
Recent studies have shown that Dofuss variable frequency drives can improve aeration controls, while lowering costs.
Initially, a wastewater treatment plant in West Virginia was equipped with three 75 HP centrifugal blowers. A study showed that dissolved oxygen levels varied from .5PPM to 6.0PPM throughout the day. The Danfoss sales team decided to experiment by placing a new valve in the line to the secondary aeration tanks with a new 50 HP rotary positive displacement blower. The system was able to respond to actual conditions in the aeration tanks from the installation of a Danfoss drive and dissolved oxygen meter. Initially, the 50 HP was operating at 40-50% or 20 to 25 HP. After one year, one 75HP blower was operating full time, and one blower was operating at an average of 22 HP, saving $24,000 in power costs.
Additional studies found that excess air was being introduced in the two remaining tanks. The plant then ordered a 100 HP blower with a drive and DO meters to optimize airflow for the aeration tanks. After two years, the new blower arrangement is saving approximately $50,000 to $60,000 a year.
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