now this is getting scary!

Tony Conner_2

... a the powerhouse of a food plant a number of years ago. Between grain dust, and having the rooftop dust collection systems fail on a production line that basically made a range of products that were powdered sugar with artificial colour & flavour added, the bacteria levels in the cooling towers could be spectacular :) You know it's bad when you pull a water sample for testing, and it's tinged purple. Ah, they're running "grape" today, and the dust collection system is being by-passed again...

Cooling towers function as giant wet-vac/air filters.

leo g_13

Link to the latest from Toronto

http://www.mytelus.com/news/article.do?pageID=canada_home&articleID=2054797

Leo G

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Dave Yates (PAH)

that would be

an evaporative air-cooled tower. Think about make-up water & potential bacterial routes for introduction to distal sites suitable for bacterial amplification. Take off the blinders that limit vision and consider the real source.

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Tony Conner_2

Cooling Towers...

...are like steam boilers that don't get all of the condensate back, and that's just the nature of the beast - it's literally "how they work". They have an on-going requirement for make-up water, plus they sit out in the sun, drawing huge amounts of air through them that is in direct contact with the water. They're prone to bacterial & algae growth and scaling. Proper water treatment (it's not rocket science) can easily handle these problems. But somebody has to regularly run the tests and add chemical, and/or check the automatic chemical feed systems.

archibald tuttle

cooling towers aren't like steam boilers but...

I beg to differ slightly.

Many cooling towers are designed not to get their condensate back and to mix vast quantities of air and condensate purpossefully for release where as steam systems are built largely upon the principle of its conservation. Of course steam systems are imperfect in this conservation, although in theory two pipe systems ought to be able to run as closed systems both in relation to air and water.

Reasonable question regarding whether the source of introduction of the bacteria was the make-up water or not. Further, significant discussion of the comparable habitats provided by a closed system vs. open insofar as suitability for propagating the bacteria is in order. Certainly the air introduced into steam systems means that they are not predmoniately anerobic as hyrdronics generally are (dissolved air and effectiveness of air eliminators notwithstanding). On the other hand, at least during heating season, the operating temperature regimen is significantly different. These kind of truly interesting questions apparently seldom occur to the reporters who write stories for the popular press. That's why I get my news here.

Brian

Aidan (UK)

Legionnaires' Disease

You have to wonder how incidents like this can still happen.

There were many incidents in UK hospitals in the late 70s/early 80s, elderly or unwell victims. It still happens, e.g.,

http://www.bbc.co.uk/cumbria/news/2002/08/04/legionnaires.shtml

My government can now immediately identify me from a computer database if I neglect to tax my car, don't get my car safety tested or insured or if I don't licence my TV (no, I do not want to discuss that one). Surely it can't be beyond human ingenuity to devise a system of tracking, sampling and insuring cooling towers throughout their lives and checking them if the routine maintenance isn't logged as carried out by a competent, licensed contractor.

This is Legionnaires' Disease, named after people who had survived the unpleasantness of WW1, WW2, Korea, etc., and who deserved much better than they got, falling victim to a bacteria that is controllable with little competence.

Dave Yates (PAH)

according to

Bruce Ketrick of Guardian Chemicals, who lectures on the treatment of cooling towers, the bacterial amplification is greatly enhanced by the very manner in which cooling towers are constructed that fosters areas where debris and biofilms (food) gather and where stagnation, or low-flow currents exist, and where the pH and temperatures are ideal. What more could a bug ask for!

Chlorine dioxide is available in submersible packets for cooling tower treatment and it will penetrate biofilms.

If you research the issues dealing with bacterial seeding, especially where legionela are concerned, it's almost universally understood the bugs arrived via the potable water make-up source.

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Tony Conner_2

You're Thinking...

... of little steam heating systems. On bigger industrial systems (they also tend to be the kinds of operations that very often have cooling towers), it's not uncommon to have 30% to 50% make-up. They also have (or better have) pre-treatment equipment and a proper chemical treatment program.

leo g_13

on the news last night

one of the investigating scientists admitted that they may never know from where the outbreak started, as the cooling towers have now been shut down for the winter season.

Leo G

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