The purification of wastewater is important in any community, but it's especially critical at the Maineville, OH, Lower Little Miami Wastewater Treatment Plant, which releases its treated water back into a state and national scenic river, the Little Miami River. Because of the river's protected status, the plant must meet the Ohio Environmental Protection Agency's most stringent standards.
A major expansion is currently under way that will nearly double the treatment plant's capacity. Dave Walling, the deputy sanitary engineer for the Warren County Water and Sewer Department, not only monitors the expansion project but was also tasked with replacing equipment on one of the existing Vertical Loop Reactors (VLRs) that was built in the 1990s.
A VLR is an aerobic biological treatment process that uses large discs that are continually rotated to move wastewater and impart oxygen for aeration. In this system, wastewater passes through a chain of four rectangular concrete tanks, each having two rotating shafts for a total of eight units. Each of the eight VLR shafts has two bearings, and a motor/reducer drive package.
When one of the shafts and an entire assembly broke apart, Walling realized that repair was no longer an option.
"Clearly, the equipment had reached the end of its useful life, so we decided to upgrade and replace the shafts, bearings, motors and gearboxes on all four tanks," Walling said. "But when we got the price from an OEM to supply the equipment, it was very expensive. I wanted a package, which is what they were offering, but wanted to see if I could work with someone locally and find a more affordable solution."
With a phone call, Walling was able to find the local help he needed, along with a package that included products with a brand name he knew and trusted.
"Dave Marsh with Kaman Industrial Technologies, and Brian Fields, a Baldor•Dodge® field sales engineer, visited me at the plant and did an onsite inspection - really studying the application so they understood what we needed," Walling said.
The team received additional help from Malcolm Pirnie, the environmental engineering consulting firm in charge of the expansion project. While problems with the existing tank were not in the firm's original scope of work, Malcolm Pirnie's project engineer, Erik Torgersen, offered his help to ensure the work on the VLR was a success.
"Dave and Brian contacted me, and I was more than willing to share information," Torgersen said. "Most of the time, plant officials will go back to the company that put in the original equipment, but this can be expensive. Warren County was willing to break that mold and work with Baldor, and I was happy to help."
With all of the information gathered, the Baldor System-1™ group engineered the individual systems. System-1 specializes in designing, quoting and ordering the required products in order to deliver a complete packaged solution to the customer. Each package designed for the Lower Little Miami plant contained a 20 HP Baldor•Reliance® Super-E® Severe Duty motor, a size 6 Baldor•Dodge Torque-Arm II™ reducer and two Baldor•Dodge Imperial™ bearings. The motor and reducer packages arrived on-site pre-assembled and ready to install.
"Because of System-1, I didn't have to try to source all of these different pieces of equipment and then worry about how to put them all together," Walling said. "The whole package works as a system, making it simple for us. I have one source of contact if I ever have any questions, plus I have the local support, which is really important to us."
After two years in operation, Walling said he is pleased with the performance of the products. He notes that because the Baldor•Dodge Imperial bearings have a concentric grip, they seem to be holding the shaft better without causing the fretting corrosion that plant staff dealt with when using setscrew bearings.
"The Imperial bearing is a much improved solution for us," Walling said. "There's less vibration, and we won't have to worry about setscrews wearing grooves into the shaft. It's good to know that we won't have to repair or replace these shafts ever again."
Walling also describes the gear reducers as robust and worry-free. Because of their design, the gearbox runs cooler, which he believes will lead to a long life. As for the final piece of the package, the Super-E motors, Walling says he has never had any doubts about their performance.
"We have used Baldor•Reliance motors throughout the rest of the plant, and I know they are bulletproof and last forever," Walling said.
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