best pump for final clarifier scum?

[chileheadcraig]

What would you recommend that can operate without a flooded suction? The scum wetwell is up to 15' deep, so I am thinking that a submersible is the only solution.... any thoughts?

Thanks.

 

[saxon]

wickedpete, You may want to take a look at AODD pumps or Progressing Cavity pumps. Both are self priming to a point.

Hope this helps.
saxon

 

[semo]

There are also centrifugal self primers and priming assisted pumps. As the self priming pumps wear, the self priming capabilities deteriorate. Some companies are better than others with their design. I like Gorman-Rupp for self-priming applications.

Depending upon the thickness of the sludge, check with the pump manufacturers on submersibles. There are submersible pumps with impellers designed for thicker liquids.

 

[Berko]

Wickedpete,

As an alternative, have you thought of a typical solids handling pump which has low NPSH R values fitted with a priming tank at the pumps suction.

I have used ABS & Hidrostal pumps in this configuration very succesfully on similar sized "Suction Lifts". Both tend to have a far better hydraulic efficiency than the previously mentioned Gormann Rupps, so significant power costs can be made.

Good Luck,

Berko