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Clogging Pump Impellers - Wastewater Collection System
Frederick Auermuller
Posted: Tuesday, August 2, 2011 4:17 PM
Joined: 9/13/2010
Posts: 2

In the past two years we have experienced a growing problem at several of our pumping stations with heavy rag and fiber buildup in the eye of dry pit centrifugal pump impellers that reduces capacity and requires manual cleaning on almost a daily basis this summer. These pumps have design capacities in the range of 10 - 12 MGD and the pump impellers are mixed flow type, have 4 and 5 vanes and are capable of passing 3 - 4 inch solids ............... but not stringy rag material. All of the pumping stations involved have operational and relatively new comminutor devices in wetwell entry channels and frankly, they have their share of problems with the rag material but are doing a fair job of shredding prior to pumping. There has been a fair amount of discussion about the disposable, supposedly flushable wipes, as being the culprit and from what I understand, there have been some meetings with manufacturers of these wipes to make them aware of the problems that we are experiencing. There have also been some efforts to educate the public about the problems that these wipes can cause in sewage collection systems. However, changing materials, manufacturing industry methods, and the habits of the public are often very difficult if not impossible. I am interested in knowing if pump manufacturers or pump owners have come up with a solution to reduce or eliminate clogging problems through impeller redesign or other means. I have a feeling that we are not alone with this problem and that many of us could benefit by the shared experience of WEF members. Any help would be greatly appreciated.   Fred Auermuller, Ocean County Utilities Authority, Central Water Pollution Control Facility, 501 Hickory Lane, Bayville, NJ  08721 

Robert Ooten
Posted: Friday, August 5, 2011 3:38 PM
Joined: 8/5/2011
Posts: 2

We had great luck with distributing flyers to the neighborhoods up stream of the pump stations.  Our pump station were relatively small, but the response was very good.


Wemco make a recessed impeller pump that is used in sludge pumping.  You will sacrafice an enormous amount in efficiency, but they will likely pass the stringy material.

Dean Falkner
Posted: Tuesday, August 16, 2011 3:49 PM
Joined: 6/21/2011
Posts: 11

Have you contacted the pump manufacturer to identify if they have alternative impeller designs? 

Dean Falkner
Posted: Tuesday, August 23, 2011 6:07 PM
Joined: 6/21/2011
Posts: 11


An idea for your hip pocket is if you can identify an alternative pump that would be able to handle this kind of flow.  For instance, we had originally spec'd Vaugn chopper pumps.  We accepted an alternative.  We raised the concern that the Vaugn would have worked.  The alternative pump manufacturer bent over backwards to get their pumps to work.
Another issue can actually be the pump suction.  Vaughn wanted a larger diameter suction piping than te alternate required.  The larger diameter suction eases flow and reduces NSP to get better flow.
Good luck and I'd love to hear your ultimate solution!!!!!!!!!!!!!