Plugged. Again. For the second time in a week, the influent pump at the River Falls wastewater treatment plant was clogged with rags.
Across the country, use of disposable wipes is on the rise. Products marked as “flushable” are making their way into the waste stream, causing pumps to plug all the way to the wastewater treatment plant. The city of River Falls was not immune to the ragging problem.
Once or twice a week, the pump was plugged. Each time it did, operators would spend at least an hour taking the pump apart, removing the clog, then putting the pump back together. Over the course of a month, the time lost was beginning to add up. Energy consumption added up too. When the pump was plugged, it still ran, consuming tremendous amounts of energy while producing no flow.
Tom Johnson, River Falls’ Wastewater Superintendent, was nagged by another thing as well, the safety of his employees.
The influent pump was located in a pit about 20 feet deep. Because it’s not technically a confined space, unplugging the pump was typically done with just one person. But not having eyes on that person for up to an hour at a time made Johnson nervous. He was especially concerned when plugs occurred on weekends, when the plant was staffed with only two people.
Sick of the plugging, and knowing that accidents can happen at any time to anyone, Johnson began searching for a solution.
He began his search online and talked to a number of sales representatives to find possible solutions. One day, a Crane Engineering Account Manager happened to stop to check in. The Account Manager took a look at the existing pumps and suggested a Cornell Cutter pump, due to its similar size and dimensions. This particular pump featured a cutter blade on the suction side to obliterate rags before entering the pump.
Johnson agreed to try one. It worked. Instead of unplugging the influent pump up to 8 times a month, it now needs attention about once a month.
Johnson attributes the success of this pump to the fact that the Cornell cutter pump is a newer technology, designed to alleviate the issues with ragging. He also notes that age of the pump plays a factor. “Age of pumps is huge,” according to Johnson. “Pumps with worn, loose tolerances will always have problems with ragging.”
Instead of continuing to put up with rags, Johnson recommends that operators investigate what’s out there. From cutter pumps, to screens, new technology is making it easier for wastewater treatment facilities to cut costs, and keep employees safe.