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JBanks

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M. Parvicella in anaerobic digester
Jan 05^th, 2012, 12:21pm

Hi, We have parvicella in our fixed cover anaerobic digesters. They are foaming up and causing huge operational issues. We are treating the mixed liquor in our aerated system to rid it of parvicella, however, we can't get it out of the digesters...Does anyone have any info on how to reduce the foaming until we are able to work it through the system?

Thank you!

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DS

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Re: M. Parvicella in anaerobic digester
Reply #1 - Jan 5^th, 2012, 12:50pm

Hi JBanks,

The Microthrix parvicella (Mpa) problem is created into the aerobic stage of your wwtp (often a seasonal problem with higher incidence in winter) where Mpa grows mainly on the FOG (likely abundantly) present in the influent towards the aeration tank. Mpa cannot grow in the anaerobic stage, but likely survives this stage (partially). so the problem originates in the aerobic stage.
1) check FOG in the influent and check fat traps (full? overflowing?). Check FOG discharges in the sewer system upstream.
2) check the DO in the aeration tank: Mpa is a microaerophilic bacterium so it grows beter when DO is pretty low. Increase DO above 2.5 mg /L.
3) Check on presence of Mpa in the recycle from the anaerobic digesters to the Aeration. if abundantly present: you can temporarily chlorinate this flow. best to get professional assistance on this.
4) Eventually chlorinate in the AT but that may not be very effective...
5) if all previous (source, root cause related) measures do not help, you might consider to use PAX dosing (Poly-Aluminium Chloride) in the aeration tank to tackle Mpa. This will however increase the Al-content in the digested sludge and which may prohibit land application of it....

best of luck,

DS

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JBanks

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Re: M. Parvicella in anaerobic digester
Reply #2 - Jan 5^th, 2012, 1:39pm

Seghers, Thank you for your post, we have made all the necessary changes to our aerobic system and had the ML and foam from both aerated system and anaerobic digesters analyzed. The aerated system is normal for filaments and the digesters have an excessive amount of MP in the foam. We can't seem to push that out. Is there any kind of anti-foam that would work on MP foam in an anaerobic digester while we continue to treat the aerated system?

Thank you!
JB

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DS

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Re: M. Parvicella in anaerobic digester
Reply #3 - Jan 6^th, 2012, 5:27am

hi JBanks,

the use of Anti Foam (AF) is far from recommendable; it never helped me in solving any case, on the contrary, in quite some cases made problems even worse.... I know it is tempting to use AF because it is easy (and that is the only good thing about it, short term easyness..), but it diverts your attention from actions that you should take, i.e.: those that act on causes. Re-study the problem again, and maybe you need another angle?

Some good measures do need time to obtain result, so patience sometimes is a requirement too....

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almar1965 God Member Offline Composting is the work of Satan !! Posts: 1291 Santiago Gender: Company or Organization: Sinquiver Ltda	Re: M. Parvicella in anaerobic digester Reply #4 - Jan 6^th, 2012, 11:07am Hi Aliuminium salts are far more effective against MP and less harmful to the rest of the system. best regards Alistair
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Re: M. Parvicella in anaerobic digester
Reply #5 - Jan 6^th, 2012, 1:09pm

IF no more M. Parvicella is added to the digester the foam should go away within a couple sludge ages. If it's possible to vacuum it off and dry it in a sand bed or put it in an empty tank and chlorinate it for future disposal that may be the best short term answer.

I've read/ heard from people having success with PAX-14, just a warning it is not cheap.

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