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Legionnaires' Bacteria Reemerges In Previously Disinfected Cooling Towers
schwit1 writes with the New York Times' unsettling report that 15 water-cooling towers in the Bronx that this week tested positive for Legionnaires' disease had been disinfected less than two months ago.
From the NYT: After an outbreak of the disease killed 12 people in July and August in the South Bronx, the city required every building with cooling towers, a common source of the Legionella bacteria that cause the disease, to be cleaned within two weeks. ... [The] city found this week that bacteria had regrown in at least 15 towers that had been cleaned recently in the Morris Park section of the Bronx. The testing occurred after a fresh outbreak in that area that has killed one person and sickened at least 12, and spurred an order from health officials for the towers to be disinfected again.
So any disinfection must be followed with a permanent antisepsis program, say a little copper in the water?
I work in legionella management in the UK, cooling towers must be disinfected every 6 months, no shit the legionella came back, it's present everywhere in the environment. The US has very lax laws for public water safety, see also New York's hideous water towers/roof tanks
But, we forgot about lazy, cheap people.
Yes, chlorine or hydrogen peroxidation would solve this, but require some method to maintain the antiseptic aspect.
Copper sheeting might shed enough Cu ions for many years, but would ne replacing as it eroded away.
Newly installed cooling towers deal with this, as this search shows.
https://www.google.ca/search?q...
Newly installed cooling towers deal with this, as this search shows.
That search clearly isn't showing me what it's showing you, because all I'm getting is a bunch of descriptions of the problem. Pathetically, even the CDC page only describes the problem, even though the CDC has renamed itself the centers for disease control and prevention. If you actually drill down a couple of links you get to their page on prevention... which only covers hot tubs! Your tax dollars at work! No, wait. They're on vacation.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Dig down, I did cast a wide net.
I found this on page 2.
http://www.hse.gov.uk/legionna...
and this, more directed search, gives more.
https://www.google.ca/search?q...
but the 2P is correct, this should be a solved problem
This is so typical of the Republicans.
This is the worst variation of the "Kevin Bacon Game." It's the Six Degrees of Political Connection, where any topic, no matter how neutral or broad in scope (like naturally occurring bacteria) can be linked to any political opinion.
Wasn't it Jim Gaffigan who pointed out the way to stop a conversation was with, "I'd like to talk to you about Jesus"?
Now it's, "I'd like to inject my my politics into whatever you just said."
Pretending this is my office full of bitter coworkers..
Speaking at a hastily-called press conference only a few hundred miles from the buildings in question, Tower-cleaning specialist and former Volkswagen Vice President Gesundheit Krappstadtz stated unequivocally that all cleaning and disinfection operations had been performed with full attention to the requirements of New Jersey's famously strict environmental regulations.
I've calculated my velocity with such exquisite precision that I have no idea where I am.
What exactly do these cool? Do they cool water or act like an AC?
I've been managing facilities and staff to maintain cooling towers for years. I've personally cleaned them, I've personally maintained them, and I've personally been responsible for the water treatment/chemistry as part of their operational and preventive maintenance.
The answer to your question is, they technically cool water, which is then piped back into a building(s) and used as a "heat sink" for any air conditioning/refrigeration equipment inside the building. In your home air conditioner, you have the box with the fan that sits outside. This box is called the"condenser". The condenser's job is to release any heat that is removed from inside the house. In that type of mechanical refrigeration, the refrigerant (R-22, colloquially called Freon) is compressed to allow for a controlled evaporation cycle inside the indoor unit (the evaporator). As the refrigerant absorbs heat from inside the home, it is pumped outside to the condenser where it releases the head into the air (in this case, the outside air is the "heat sink"). That is, the fan on the condenser pulls outside air across the coils where the hot refrigerant is being pumped, and the heat transfers to the outside air, cooling your house.
In large commercial applications, it is often more efficient to use water based systems to achieve this. In this method, the refrigerant that has absorbed the heat from inside the facility is dumped into what's called "condenser water". The water absorbs the heat, and the cooled refrigerant goes back to the air conditioning systems in the building to absorb more heat. The condenser water is pumped up to the cooling towers where it is filtered through several screens while large fans pull outside air across them (similar to the home system). The combination of the water flow patterns, air velocity, and evaporation will cool this condenser water, allowing for it to be sent back to the indoor air conditioning systems so that it can absorb more heat and start the cycle again.
I mention all of this to say this: the ONLY reason this type of contamination is happening is because of improper maintenance. Period. Water treatment systems are just about idiot proof. So, while we may not hear about it, I guarantee someone, somewhere took a short cut. Maybe it was the end of the fiscal quarter and someone was under pressure to save money, so they postponed the delivery of the aquastat chemicals for a couple of weeks to make budget. Maybe a maintenance engineer didn't really do his rounds inspection that day and so he didn't see that one of the chemical feeder pumps had tripped out on overload. Maybe the maintenance workers didn't want to spend a few hours inside one of these steamy boxes cleaning out additional algae buildup. It's not a glamorous job to say the least, but not terribly difficult in the grand scheme.
People should not only lose their jobs and licenses for this, people absolutely deserve litigation for this. This is nothing short of negligence.
because it provides a good environment for them. It is not at all surprising that the bacteria would be found in a recently disinfected cooling tower. The only way to stop that from happening is to somehow make the cooling tower environment a less friendly one for the bugs.
They still use a compressor, but instead of running normal outside air across dry coils, they run the air across wet coils. The evaporation makes the coils cool faster and more efficiently, at the cost of losing water. The non evaporated water is reused and pumped back to the top. Because the water is reused it can get kind of nasty and needs frequent cleaning. (Note I'm a licensed technician, but I don't work on cooling towers).
that's actually the problem with most technology
nuclear for example
i haven't a single doubt that we have the technological means to maintain nuclear plants forever without a single accident
but what we don't have is the social and political means to do that
money is always being cut, indefinitely, and the people making that decision are not exactly technically proficient. the incentive to cut costs form the general public and bosses who want to trumpet cost cutting trumps all other concerns, because other concerns, no matter how vital, are simply not understood. combine that with a technical person that responds with anger and arrogance at the idea of vital safety mechanisms being underfunded, the manager will simply disregard him or her as a person with a personality problem, and then disasters happen
people who champion nuclear, especially on a website like this, understand the technology well, and are correct when they announce we never have to have a nuclear accident ever again due to technological issues
but they don't consider the political and social aspects of our species that means vital funding of safety mechanisms and maintenance of absolutely crucial technology *will* be broken. it's simply a matter of when, not if
and then people who champion nuclear get angry at people like me, and accuse us of not understanding the technology. oh we understand the technology is wonderful. but it is you who doesn't understand humanity
the imperative on cutting costs and doing as little effort as possible is always trumping all other concerns. always. and people like this wind up being the managers, not the underlings. they can't be fired, they do the firing
incompetence is a force that destroys everything. sober up and accept that
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Sure, no problem. there are closed type systems, but when you have Cooling Towers, it's an open system. That is, there's a secondary chilled water loop that circulates inside, and it dumps its head into the primary loop through a plate and frame heat exchanger. The primary loop gets pumped out to the cooling towers, where it goes through the cooling tower "fill" which is a scheme of different diverter surfaces to separate the water into thin streams running along flat surfaces. Outside air is then drawn across the fill, and that removes the heat and aids in evaporation of the water. Any water that is evaporated away is replaced with fresh "makeup water".
:-)
As the water is being drawn across the fill, it starts to evaporate and also atomize (meaning that the streams of water break up into tiny droplets that are technically still liquid, but are light enough to be carried away in the moving air stream). As these water droplets are pulled into the outside air, they can be carried anywhere. Often, cooling towers are located on the roof of buildings. The other thing that you'll often see on the roof is the building exhaust fans and the fresh air make up fans. If the fresh air makeup fan inlets are located anywhere near the cooling tower, it is very possible to have those same tiny water droplets get sucked into the intake, and pumped into the building along with the fresh air makeup.
Mechanical Engineers usually design the location of these intakes to be far enough away form the Cooling Towers to prevent infiltration, but wind currents can be a little hard to predict. Also, if the Cooling Tower isn't being operated correctly, there can be more water atomization than there should be. For example, if the Variable Frequency Drives (VFDs) that control the Cooling Tower Fan speed isn't set up right, it can run too fast and pull out more water droplets than it should be (this should ordinarily be kept to a minimum because makeup water isn't cheap, and it's not "green" to use too much water).
Hope that helps.
A useful concept here is "Social Tech Level". We have the tech for safe nuclear plants, but we may lack the social tech. Much as, say, Panama had the tech to maintain the canal for many years before it had the social tech. You need both the technical know-how, and enough resources left over after corruption to actually fund it.
For all our competing systems of government, we don't seem to have made much progress in "social tech level" in the past 100 years. If anything, the basic systems of administration haven't improved in this regard, but the skill in corrupting them has gone way up (whether corporate corruption or good old fashioned Old Boys Network corruption).
Whether Socialist, Communist, or Capitalist, each in it's own way we can't seem to get the job done, so I think it's something quite distinct from economic system. I think there's just a problem of administration, transparency, and reporting results to solve. E.g., I don't care if the road gets built by the mayor's nephew, I care whether it's build on-time and to-spec, and how much it cost - if it merely cost more than it should, that's the least-bad problem. Cost-cutting is a good thing, but it takes a back seat to getting the actual job done.
Socialism: a lie told by totalitarians and believed by fools.
It's said that the Roman engineers responsible for the construction of a support arch for a bridge or aqueduct were required to stand under it when the support scaffolding (used in construction) was removed. They had a very personal incentive for making sure everything was done properly.
Likewise, the reactor engineers on a nuclear submarine have a very personal incentive for making sure everything is done properly, over and above military discipline.
Do we even know that, in this case, the cooling towers were even properly disinfected in the first place? Maybe the building managers and whoever else is responsible should be required to spend the day after disinfection exposed to a nice mist of cooling water...
-- Alastair
Or perhaps we understand that quite well. And decide that it's not that big a problem.
Civilian nuclear power deaths in the USA, to date: zero.
Military nuclear power deaths in the USA, to date: four? Basically the people in the room with the test reactor (that fit in a bathtub) when someone pulled the control rod (yes, there was only one) out by hand.
Hmm, 70 years of nuclear power in the USA, with so few casualties. I could wish the highways were that safe. Or Airline travel. Or trains. Or COAL MINING. Or Oil drilling. Or even hydropower dams.
Hell, more people have died just this year installing solar cells than have died in nuclear power accidents in the USA in all of history.....
"I do not agree with what you say, but I will defend to the death your right to say it"
We understand humanity. You don't understand statistics. When there's a nuclear accident, it's big and scary and gets reported by all the press. When there's a coal, wind, or solar accident, it's small and doesn't get reported by the press. If you base your statistics on what's reported on the news, you get a skewed view of the dangers of these power sources. It's like planes vs cars. Every airliner crash gets reported on the national news. But car accident fatalities are rarely recorded. The erroneous reporting bias is large enough that some people are deathly afraid of flying, even though you're statistically more likely to die in a car accident on the way to/from the airport than on the flight itself.
Likewise, nuclear is the safest power source man has invented. Despite the accidents, despite the human failures you cite (Chernobyl and Three Mile Island were caused by operator error). It has produced the fewest casualties per unit of power generated of all power sources. Did you know that the month of the Fukushima accident, when zero people were killed by nuclear power, one person was killed by wind power? A school in Ohio forgot to lock the gate to their wind turbine. A student climbed up it, and fell to his death. Human error affects all power sources, not just nuclear. If anything, nuclear is safer because of the increased scrutiny it gets.