nocardia bacteria

K N and P J Harris ecoli at
Fri Nov 10 09:18:43 EST 1995

> ==========
> bionet/mycology #567, from parex1 at, 2706 chars, 7 Nov 1995 
> ----------
> Article: 2602 of bionet.mycology
> Path:!!btnet!!d
> .net!news
> From: DON KRESS <parex1 at>
> Newsgroups: bionet.mycology
> Subject: nocardia bacteria
> Date: 7 Nov 1995 15:03:25 GMT
> Organization: CDC Internet - 423/842-5709
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> I am a layperson in this subject so forgive any biological 
> please.
> A problem with the local municipal sewage water treatment plant is 
> occurring in my area and an organism they said had been identified as 
> "nocardia filamentous bacteria" is the culprit.  The effect the 
> organism's growth has is to cause a brownish foam several inches thick 
> appear on the surface of the water in the clarifier tanks which is a 
> final stage of the water treatment process.  The surface skimming 
> that the tanks are equipped with are not designed to handle this 
> thickness and consistency of foam.  The net result is foam carryover 
> the effluent stream.  This is environmentally unacceptable and they 
> looking at remedial measures such as physically removing the foam 
> vacuum trucks on a temporary basis and improved surface skimming 
> equipment for the long term.
> The problem has been a recurring one over the last ten years and is as 
> bad as it has ever been right now.  The plant operators have not been 
> able to establish a cause and effect relationship to explain this 
> phenomena.  A mechanism that was described is that this bacteria 
> itself to oil and\or grease and floats it to the surface.  The plant 
> a high throughput and the sewage has a short residence time.
> My focus is to attempt to identify the root cause of the problem.  
> Presumably this bug is always present and will grow to objectionable 
> levels only under certain conditions.
> Questions:
> Am I in the right newsgroup?
> Has anyone seen this sort of effect in a sewage treatment plant and 
> the root cause identified?
> Are there certain compounds in the sewage water entering the plant 
> would cause this organism to proliferate?
> Could waste water from petroleum refining which may contain 
> trace amounts of hydrocarbon compounds create favourable growth 
> conditions for this organism?
> Any tips on other questions jor things I should be considering?
> Any references to other souces of information would be appreciated!
> DEKress
> Ontario
> Canada
Never heard of this one before but then I'm a soil rather water person. 
The Nocardia group are pretty resourceful and traces of hydrocarbons 
could be right up their street. Air stripping might be an idea but the 
cahnces are that these hydrocarbon traces are not the most volatile. It 
would be interesting to check the water pH. Only a guess, but I would 
bet that the pH is in the 7.0 to 8.0 region when these become a pest. A 
little judicious acidification might do the trick.
Peter Harris,
Reading University, UK.
AKA P.J.Harris at

Opinions are none but mine own.

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