Replacing Equipment and Improving Energy Efficiency Mark Klaus, MRWA Energy Efficiency Circuit Rider If your first thought is, “How much extra will that cost?” this article is for you! Missouri Rural Water Association personnel recently performed energy calculations for a lagoon aeration project at Cleveland, Missouri. The city of Cleveland is a Cass county community with an estimated population of 660 persons. Special thanks to city of Cleveland representatives: Public Works Director, Mike Gregory; Water Superintendent, Randy Maynard; Public Works Assistant, Doug Neller; Board member, Ray Morgan; and City Administrative Professionals, Ms. Dana and Ms. Tasneam. Your dedicated teamwork is appreciated. The city’s wastewater collection system has three lift stations with treatment provided at a two-cell lagoon. The primary lagoon cell utilized six “splash style” aerators which were equipped with 7.5 horsepower motors. Three of the six aerators were operated at a time, utilizing a zig-zag pattern to provide mixing. Two of the aerator motors expired, requiring replacement. Of the two, the second motor terminated service toward the end of 2019. Cleveland representatives proactively reviewed various replacement options for the expired aeration units. Various manufacturer representatives viewed the facility, answering questions and providing formal prices. A spreadsheet was developed, listing parameters for aerator replacement which included equipment pricing, energy use, yearly maintenance requirements/costs, local availability of parts, and if in-house maintenance was possible. This completed document was provided to the city council along with the preferred choice. The city council approved the purchase of the aerator with the highest energy savings. The estimated energy savings will provide a fast payback on this investment. The following table notes the number of motors, total horsepower, and estimated energy savings for the various options.
After a delay associated with the COVID-19 pandemic, the new lagoon aeration unit was delivered and installed at the Cleveland wastewater lagoon on May 4, 2020. City personnel assisted the equipment manufacturer during the installation process. The five horsepower, C and H Systems Gen-Aer unit was custom built for the Cleveland lagoon. The unit was upsized, providing additional aeration capacity. Within a few minutes of startup water circulation was noticeable. Two days later, I received a 42
