Return Activate Sludge Pumping
Return Activate Sludge Pumping
(OP)
We use three internal or closed screw pumps to lift our RAS from a sump up 25 ft at a rate of 8000 GPM. We are experiencing a lot of cracking on the head flights and after several weld repairs / sensitization etc we are in the position that we need to replace/ upgrade.
What's everyone's thoughts on using a screw pump or a submersible centrifugal pump? I'm guessing for such a high flow, low head appliation that you just can't beat a screw pump for HP - is there any other reason? There's been talk about shearing the bugs with a centrifugal but...
What's everyone's thoughts on using a screw pump or a submersible centrifugal pump? I'm guessing for such a high flow, low head appliation that you just can't beat a screw pump for HP - is there any other reason? There's been talk about shearing the bugs with a centrifugal but...





RE: Return Activate Sludge Pumping
Compared to other pumps, submersibles are lower efficiency. The screw pump efficiency ranges from 65 to 85%
The submersible pump effiency probably ranges from 40 to 50%.
The annual power cost is probably around $24,000 at 7 cents per kw so you can not justify the pump based on power cost.
The screw pump operates at a constant speed. You would have to install controls to regulate the flow from the submersibles.
You would also have to build a wet well for the submersibles.
RE: Return Activate Sludge Pumping