If anyone remembers my posting "High Ammonia Is Beating Me", well, it has gone down hill very quick.  Not sure I can turn it around before a non compliance happens.  

I was getting my ammonia down, some <1, a 2 and so on. Then it fell apart.  My Aqua-Aerobic disk filters keep clogging up.  They have been online for 2 years.  We went thru the manufactures cleaning procedure but to no avail.  My clarifiers are fine one minute then the next they are spewing solids over the weirs which clog up the filters.  Now my effluent and supernatant is so murky my UV is going to be compromised.  we have new disk filter clothes to put on one of the filters but are scared to in case there has been something in the water that has caused this.  The manufacturer says that nothing should build up inside of the filters clothes but something has.

Has anyone come up on anything like this before?  Anyone with these kinds of disk filters?  I was recovering from over wasting and getting the plant back around.  Can it be that my sludge is so young in just starts rolling over the clarifiers?  HELP!!!!!!!!!!

I reduced the wasting but it allowed for the solids to build up in the clarifiers, which then came over the weirs.  I am at a loss on how to proceed.  This is a package plant with clarifiers 10' deep, 12' diameter.  So, 3.14 *6*6*10*7.48=8455 gallon clarifiers x2.  The aeration is keeping the solids so fluffy that they won't settle.  Right now I am at 45 minutes run time on the blowers with 15 minutes off.  I was thinking of going to a 20/20 split to try and help the settling.

kimmy wrote on Mar 19^th, 2012, 12:55pm:



Yes.  The disc filters with a vacuum head in contact with the media CAN experience this.  The head can actually plow attached biomass through the media onto the other side.  Several manufacturers' filters have experienced similar phenomena in some circumstances.  This can occur on both polyester and wire cloth filters.  Excessive instantaneous forward flow rates can also cause higher TSS in the effluent.

New segments with fresh material may temporarily "cure" this by providing a surface with the correct and undamaged surface and pore size and by removing any current interior growth with the old segments.  However, the phenomenon can repeat in short order if you do not solve the root cause of getting bulked/poorly formed sludge to the filter(s) and getting it to settle properly instead.  

Muddy Creek?  I believe Crocker & Assoc. is the AAS representative in that area.  If that is your region, Dennis or his staff should be able to provide their historical experience.  They may have suggestions for minimizing the problem while the apparent non-settling floc is resolved.

Temporary Solutions

Is there any surface foaming?  Mechanically removing the foam may help.  It may be especially helpful if there are filamentous bacteria present by simply removing the largest populations.  

As a temporary fix, you might want to research the possibility of the addition of lime to help increase the sludge mass and add some alkalinity.  If I understood the reported numbers in your previous thread, the pH is not excessive and lime might be tolerated, or even beneficial.  

If alkalinity is a concern you might add fine ground earth clay to affect a similar increase in sludge mass.  This can have a minimal effect on the process other than greater sludge mass, but not a markedly greater sludge volume.  However, before adding clay you must confirm its compatibility with the various equipment manufacturers for all equipment exposed to the mixed liquor, as clay can cause abrasive damage to pumps, bearings, seals, and other devices.  

Polymers could also possibly help with the bulking, but this is a temporary solution and generally results in higher sludge volume production which may counteract your efforts to increase sludge age.

Long Term Solutions

What is the RAS rate?  If it is not excessive, you might be able to increase it to help lower the sludge level in the clarifiers.  The overall HRT of the plant will not be altered, but the location of the majority of the sludge may be improved.

As previously asked, is there aeration in your 100K EQ tank or can it be aerated?  Moderate aeration with simple coarse bubble diffusion or submersible mechanical units here may help by keeping the biology active and mixed, and by carrying D.O. into the reactor where the demand for aeration could be reduced, thereby allowing more settling time and/or less aeration/mixing closer to the clarifier(s).   Since you do not report a nitate limit, denitrification (or the lack thereof) would be of minimal concern so the additional incoming D.O. should be tolerated.

Further, improved management of the EQ tank(s) may help moderate some of the variations in diurnal flow, keeping peaks (and washout potential) to a minimum and also minimizing the periods of plant idle with no forward flow.  Both of these improvements can help get the clarifier operating within a more suitable forward flow rate and prevent some of the washout.  The EQ capacity seems to exceed 2Q and should therefore allow for complete control and very stable forward flows, with the obvious exceptions of periods of high INI or storm events.  One of the key elements in managing this in smaller plants is not simply the level of the EQ tank but the combined level and rate of change of the EQ tank.  This apparently eludes many control engineers’ current schemes, but I can say from personal experience that this is not terribly difficult to implement.  A few rungs of logic, understanding of diurnal flow patterns, and judicious monitoring of the analog basin level can make a substantial difference.

Considerations

These options are in addition to the above mentioned steps to analyze and improve the sludge settleability.  F:M, SRT, influent FOG levels, and temperatures might also be significant.  Peeking in the 'scope for filaments, collected gasses, or healthy organisms should be enlightening.  

Another item which I did not notice is whether you are supplementing the plant with nutrients, and if so, with what material(s)?

A full list of operating parameters and system schematic would certainly help eliminate a lot of random guesswork.  Your system provider should be your first step in seeking a solution, but providing the data here may allow for a more comprehensive reply than even the manufacturer can offer.