AceOps: The National not-for-profit

Professional Certified Operators Association

A not-for-profit ALLIANCE of Certified Operators">

AceOps: The National not-for-profit

Professional Certified Operators Association

A not-for-profit ALLIANCE of Certified Operators, Laboratory Analysts, Inspectors, and Specialists

   Ask PhilK...

Phil Koundakjian was honored by the IWPCA in 2005 for his dedicated service to the wastewater industry in Iowa! 

Operator Advancement Award Grade IV Wastewater Treatment Plant 2005.   Phil accepted this award on behalf of the City of Des Moines.

           

Recent Q&A:

SEM:  PhilK, AceOps get lots of requests from folks looking for help in getting ready for the certification exams, what do you recommend?
Dr Phil:  One of the best tools available are the AceOps EasyTest CDs.  I'm very proud of these because I created them and we've gotten so many glowing reviews on how they are helping folks.  To learn more, click on our EasyTest link.

SEM:  I was asked "what does it mean when the blanket in a settleometer settles unevenly or it settles with a vortex and then the sides rise at or before 30 minutes?  Old sludge/denitrifying?  Nitrates?  Other??"

PhilK:  If it settles reasonably I believe no problem.  I would think it is how it  was mixed in the settleometer if you do it in circular motion  good chance of what you see.  That is why you use a paddle ago back and forth.  Also is the settleometer the right size or is it a graduated cylinder?  Also, do a OUR/RR and a bug count if you can.  AceOps is passing this question on to more experts for comments and we'll post them as we receive them.

Here's John Esler, CPE Services, Enfield, NH thoughts:

That's a pretty graphic description!!! If it rises in 30 minutes ..... or ..... almost any time at all, it's because it's denitrifying ...... which means that there are nitrates in the MLSS.

Here's Ron Schuyler, RTW Engineering,  Denver, CO thoughts:

Vortex usually means poor technique – the mixing was done in a circular back and forth motion rather than the across and back motion.  It also usually means that the movement was not stopped before the test started.  The only other cause of center depression that I have seen is bulky sludge that settles in the center faster than on the edges.
 
Rise in 30 minutes means denitrification.  Old sludge with nitrate present due to nitrification.

Here's Kevin Waggoner, Waggoner Solutions, Donnellson, IA thoughts:

Also, I have been thinking about the vortex effect.  This may be a rapid settling sludge in a narrow settleometer.  As the sludge settles rapidly, it may drag on the wall of the settleometer.  If this is the narrow style settleometer, switch to the wider style and see if the vortex persists.

The same conditions mentioned below still apply for nitrification.

Typically, uneven settling indicates filamentous bulking,  If you have a clear separation between the top and bottom sludge blankets,

it may be indicating denitrification.  Denitrification in the settleometer usually occurs within the first twelve to fifteen minutes of the test.

I would recommend continuing the test for 1 to 2 hours to see what the blanket does.

If you have questions for PhilK, please click this PhilK link to ask your question!!!