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| | | Forum Member
 
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Last Login: 8/29/2008 3:08:56 PM
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| | Were looking to purchase two new centrifuges for dewatering our digested sludge. We are currently using a centrifuge so were familiar with them. Sure like to hear some feed back on the good,bad and the ugly. |
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Supreme Being
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| | One issue with high G centrifuges is that the high shear energy rips open cells and the nutrient then cause a regrowth of coliform and other organisms along with a serious odor problem. We rated our odor in DUs, Dead Animal units! WERF has done a bunch of research on this. It would be important to visit and/or call plants with the exact model you are thinking about using. At one plant side by side centrifuges by the same manufacturer, but different models, where the high solids one made stinky cake and the other one didn't. |
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| | | Junior Member
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Last Login: 9/3/2008 1:53:45 PM
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| At the WEF biosolids show earlier this week, a presentation was given by Dr. Mohammed Abu-Orf comparing performance of Belt Filter Press and a Centrifuge at Ocean County Utilities Authority, NJ. The plant ended up going with the BFP but the recommendation was given that, if possible, piloting makes a lot of sense so a real comparison can be made for your sludge. I've heard this sentiment elsewhere. I suspect that it's a combination of varying effectiveness under different conditions in addition to the free market we enjoy that contribute to the fact that there's more than one way to skin the dewatering cat.
I know a lot of centrifuge manufacturers have pilots available...Flottweg, Alfa Laval, etc. so it might be worth seeing what it would take to get something like that going. The local reps are a good place to start. If you're not sold on a centrifuge, you could try some other technologies and see some consequences firsthand. |
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| | | Junior Member
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Last Login: 8/21/2008 11:15:33 PM
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| | Andritz makes a good one we have had luck with. They are Texas Based. |
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| | | Junior Member
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Last Login: 7/21/2008 2:36:47 PM
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| You are asking a difficult question.
Every centrifuge has a market, so you have to figure out what you need
Do you have a high disposal cost? Over say...$40/wet ton
Do you expect to run the centrifuge a lot more than 30 hours per week?
If you answered no to both questions, than the lower cost, not so well known brands will probably be more cost effective.
If you answered yes, then you probably would do well to consider spending more money for a more rugged, hopefully higher performance one.
Obtain copies of the instruction books of models you are considering, and judge if they contain enough information therein to maintain them
Ask all vendors for installation lists and call several and talk to both maintenance persons and operators. Visit centrifuge installations in your area
If the fog the vendors throw up is really thick, (Here comes the crass commercial) I consult with engineers and owners to help them make such choices.
Peter LaMontagne
peter@thecentrifugeguys.com |
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| | | Forum Newbie
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Last Login: 7/9/2008 5:47:38 PM
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| Some of the top names include Andritz, Alfa-Laval, Westfalia....
bnr_guru |
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| | | Junior Member
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Last Login: 8/22/2008 8:33:59 AM
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| | We have just finished a selection on ATAD/BNR sludge (don't ask why we have this process). We had some rather bullish claims by a high speed centrifuge co, which were not bourne out on-site (in terms of cake solids and just flocculation at full throughput). We also had an offer from suppliers of large bowl, slow speed centrifuges (i initially thought it was old technology). Both were trialed onsite and the large slow speed centrifuge won by a mile. The moral of the story is if one centrifuge seems ahead of the rest and you are ready to commit to it trial it on-site. I know it is a big effort but it saves a decision of buying one that cannot meet the spec. So why is a big slow speed machine better? The lower Gs cause less breakup of the polyelectrolyte-sludge floc. Plot the suppliers recommended poly dose against bowl revs or Gs and you will end up with a line of positive slope. This plot can also weed out possible bullish claims regarding poly doses! Poly is a significant operating cost. Also these big machines have larger bowls, which mean greater detention times for dewatering and thus make up for the lower Gs. Regards Grant H
Regards
Grant H, Australia |
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