Sludge mixing pumps_VSD or Fixed speed

Sam1390 · Jan 31, 2024

Hi all,
I am working on a wastewater plant and there are a few mixing pumps e.g. primary sludge tank mixing pump , digested sludge tank mixing pump and Anaerobic digester mixing pumps.
some vendor offered Fixed speed while the preference is VSD.
Can you please let me know for these specific applications which one is better and why?

bimr · Feb 1, 2024

If you are just transferring sludge, the fixed speed is fine. You can operate the pump on a time clock and you can keep the velocity up so the sludge doesn't settle out. If you are transferring sludge to another process such as a dewatering unit, you would want VSD so the pumping rate can be matched to the processing rate.

Sam1390 · Feb 9, 2024

Thanks bimr for your response .
the pumps I was taking about is the recirculation pumps not a transfer pump.

bimr · Feb 11, 2024

Mixing pumps may be fixed speed as there is little benefit to adjusting speed. These are generally low HP pumps and little energy savings with VFD's.

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Sludge mixing pumps_VSD or Fixed speed

Sam1390

Chemical

bimr

Civil/Environmental

Sam1390

Chemical

bimr

Civil/Environmental

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