Bacteria growing in distilled water
Edtec Sales
I am running the following experiment on my desktop.
One month ago, I purchased some distilled water in 1 gallon
polyethylene jugs. The description on the jug says "Filtered through
activated carbon, steam distilled and ozonated".
I then purchased three stainless steel mixing bowls (not very high
quality stainless, a magnet has a weak attraction, the bowls were
made in India, and they cost $1.19 each). I cleaned them with
detergent 3 times, rinsed with tap water for 15 minutes, then rinsed
with distilled water 5 times.
I then put put the distilled water in the bowls like this...
-----
/ \
/ \
\-------/ \-------/
\ H2O / \ H2O /
----- -----
...and left it alone in an ordinary office environment.
Then I let it sit for a month.
My open bowl is has a bunch of what looks like very much like
short white threads in it. I think that they are some sort of
filamentlike bacteria. The closed bowl looks like it may be
starting to have them as well, but in very small quantities.
Anybody have an idea what they are? A Latin name would be nice...
Why am I doing this? I have a new boss, fresh from Japan, who
says that we can run Deionized water of the sort used in
semiconductor manufacturing in a recirculating system with a
stainless steel (316) tank with brass fittings (*another* bad idea!)
for years at a time (with more deinozid water added to keep up the
purity, always mixed with the old) with no effort to control
biological growth. I am attempting to show him the error of his ways.
Any comments on such a boss are welcome; I plan on copying all replies
in this thread to him.
Will these bacteria (?) become bad enough to clog pumps/valves?
Edtec Sales
In article <Pine.GSO.3.95q.970629122331.26798B-100000@earth>, c...@glink.net.hk wrote:
Thank you for taking the time to help me with understanding my
experiment. It's nice to have help from an expert.
>I think the above experiment does not give fully demonstrate your thoery
>as your boss' idea is to have a flowing system so if you design your
>system to eliminate the accumulation of stagnant water you should have low
>risk of microorganism growth.
He has designed in quite a few places where the water doesn't flow,
plus the system may be turned off for many months at a time. I will
set up another experiment with a small teflon pump and see if it makes
a difference.
>As your experiment have stagnant water for a month, I am not surprised
>that that you have fungus growth ( I don't think it is bacteia as you
>probably need a microscope to see bacterial threads).
Fungus! That never occured to me. I was thinking that the threads
were collections of many bacteria, not individual bacteria that are
big enough to see. Maybe I should order a microscope (not that I
would understand what I was seeing)...
>Also another way to eliminate fungus growth is to have a good Quality
>Assurance so to make sure that you eliminate the chances of spore
>contaminaton of the deionised water being fed into the system. (Some sort
>of closed system migt be in order from your deioniser to your tanks)
Is this practical? I assume that even one spore would grow into a
thriving colony. Is it possible to eliminate every single spore?
Eric Lucas
cyc wrote:
> As your experiment have stagnant water for a month, I am not surprised
> that that you have fungus growth ( I don't think it is bacteia as you
> probably need a microscope to see bacterial threads).
You've never brewed beer, have you? If you have a friend who does, take
a look around the neck of the bottle sometime. If his brew has a
bacterial infection, you can see the little colonies of bacteria growing
on the surface of the liquid and on the glass. I wouldn't rule out
bacteria in his case.
By the way, why would stagnancy affect bacterial (or fungal) growth in a
closed system? I believe that, in nature, stagnant ponds have rich
biota mostly because they are a closed system, and nutrients tend to
collect there, plus something that starts to grow there stays there
rather than being swept away. His circulating water system is similarly
a closed system.
One difference to keep an eye out for--if the circulating system is
truly closed, then lack of O2 will encourage different types of bacteria
to grow than you have in the open bowl experiment.
Eric Lucas
cyc
On Sun, 29 Jun 1997, Eric Lucas wrote:
> > As your experiment have stagnant water for a month, I am not surprised
> > that that you have fungus growth ( I don't think it is bacteia as you
> > probably need a microscope to see bacterial threads).
>
> You've never brewed beer, have you? If you have a friend who does, take
> a look around the neck of the bottle sometime. If his brew has a
> bacterial infection, you can see the little colonies of bacteria growing
> on the surface of the liquid and on the glass. I wouldn't rule out
> bacteria in his case.
Sorry I have never brewed beer, would love to try some day as alcohol is
way too expensive here.
Any way back to business, yes it could be bacteria although one can
visibly see bacterial cultures, they tend to be evenly rounded colonies
rather than in a thread like appearance. So actually I was referring to
the thread like structures in the water which was very visible.
I agree with you that one cannot rule out bacteria and indeed you may have
bacterial infection in the water but it does not neccessarily manifest in
visible structural forms, nor indeed yeast contamination which is very
common when we do cell culture in vitro.
>
> By the way, why would stagnancy affect bacterial (or fungal) growth in a
> closed system? I believe that, in nature, stagnant ponds have rich
> biota mostly because they are a closed system, and nutrients tend to
> collect there, plus something that starts to grow there stays there
> rather than being swept away. His circulating water system is similarly
> a closed system.
Actually I do not know whether the water will be used or not, I thinking
on the line that the water in the tank has some other purposes, in that
it serves as a buffering supply for some operations, so in that case it
would not be a stagnant system, the trouble I was pointing to is that if
the system design leave a section where water is stagnant it may encourage
growth of microorganisms.
The closed system I mentioned was the link between the water deioniser and
the tank. As the water from the deioniser should be sterile (if the thing
is working probably) then a closed connection between the deioniser and
the tank would decrease the risk of contamination significantly.
Regards,
C.Y. Cheung
Microbiology Research
University of Hong Kong
cyc
On 29 Jun 1997, Edtec Sales wrote:
> He has designed in quite a few places where the water doesn't flow,
> plus the system may be turned off for many months at a time. I will
> set up another experiment with a small teflon pump and see if it makes
> a difference.
Oh I thought the system will be continuously flowing, if it will be
switched off for many months then you certainly run the risk of
microorganism growth.
> Fungus! That never occured to me. I was thinking that the threads
> were collections of many bacteria, not individual bacteria that are
> big enough to see. Maybe I should order a microscope (not that I
> would understand what I was seeing)...
Actually one cannot rule out bacterial growth as I explained in my post to
the other response to your post. Generally speaking fungus is thread like
and tends to grow more readily in lack of nutrient condition like in
deionised water, but this is only relative. Bacteria can grow , but
their colony tends to be rounded. You can also get yeast (another common
type of fungus) which do give rounded colonies in culture.
> Is this practical? I assume that even one spore would grow into a
> thriving colony. Is it possible to eliminate every single spore?
Ofcourse we cannot guarantee to eliminate contamination down to a single
spore. We can only try to minimise the chances of getting contamination
and one good way of minimising contamination used in cell culture
laboratries is to keep the system away from possible source(s) of
contaminatin. In your case I would have thought a direct closed link
between your deioniser which should produce more or less sterile water to
your water tank would do the trick. If you clean the whole system
including your link by say fumigation after installation but before
operation you should then have quite a clean system.
A final note, I noticed that you are only concern with the thread like
structures clogging up your pipes, if you don't need the water to be
microorganism free for subsequent operations I don't think slight
fungus or bacterial growth will clog up your pipes.
Doug Brown
You do not say what you (or your company) will be using the DI water for.
An answer therefore is highly speculative.
However, FWIW, here goes. The water you purchased may well have been
deionized, filtered and steam distilled, but unless it was packaged under
sterile conditions spores and bacteria are bound to enter it and begin
their life cycles. Depending upon the level of purity in the original
product, there may be varying levels of minerals to enable these organisms
to live.
Also, you are using vessels of admittedly unknown quality and makeup.
This, coupled with your cleaning methods may have introduced enough
minerals and nutrients to allow some level of biologic reproduction.
I would not use this type of simplistic, low tech experiment in any attempt
to persuade anyone of anything, let alone getting in the face of my boss
with possible dire consequences.
Also, you are somewhat pejorative in describing your new boss as "fresh
from Japan" without any mention of what qualifications (if any) he has to
form the basis of his opinion. Again, this type of mind set seems ill
suited to career longevity.
Edtec Sales
In article <01bc84f0$902829e0$6925...@dlcwest.dlcwest.com>,
>
>You do not say what you (or your company) will be using the DI water for.
>An answer therefore is highly speculative.
We will be selling these to a wide range of customers in North America,
Europe, and Asia. The units have to be usable by a wide range of
customers with a wide range of D.I. water supplies. Some will run 24
hours a day, and some will be spares that are expected start working
after sitting stagnant for months or years. Some will see 18.3 megohm
ultrapure water, some will see "Deionized Water" that is little better
than tap water. Some will see water already full of bacteria.
I am the one who will have to fly to Korea or Germany if one of these
fails, and I believe that the units need some antibacterial measures
for reliability. I want to incorperate a U.V lamp. My new boss, with
no education or experience with Deionized Water, has mandated that we
do no such thing. Yet I will take the blame if it doesn't work...
>However, FWIW, here goes. The water you purchased may well have been
>deionized, filtered and steam distilled, but unless it was packaged under
>sterile conditions spores and bacteria are bound to enter it and begin
>their life cycles.
The fact that it sits on the supermarket shelf for long periods of
time makes me believe that the "Ozonated" step is sterilization, but
of course that goes out the window when I remove the lid, so I agree
that there are probably spores and bacteria. I also believe that the
customer's units will also contain spores and bacteria, considering
that we have the tanks welded in one shop, buy the fittings from
another, the tubing from a third, all with no effort to be sterile.
>Depending upon the level of purity in the original
>product, there may be varying levels of minerals to enable
>these organisms to live.
>
>Also, you are using vessels of admittedly unknown quality and makeup.
>This, coupled with your cleaning methods may have introduced enough
>minerals and nutrients to allow some level of biologic reproduction.
True, but also true at at least some customer sites.
>I would not use this type of simplistic, low tech experiment in any attempt
>to persuade anyone of anything, let alone getting in the face of my boss
>with possible dire consequences.
I believe that manufacturing a defective product will hurt my career
much more than opposing a boss ever will. I am a design engineer, and
can get a another job within two days. When a manager forces me to
make a bad design, I must fight. It's my job to do so. If push comes
to shove, senior management will probably reassign him and keep me, but
I really want to quietly convince him *without* senior management ever
finding out that he is forcing dubious technical decisions on me.
>Also, you are somewhat pejorative in describing your new boss as "fresh
>from Japan" without any mention of what qualifications (if any) he has to
>form the basis of his opinion. Again, this type of mind set seems ill
>suited to career longevity.
Let me be more specific;
Zero English skills, communicates by pictures.
Translator available, but he chooses to not use translation in most cases.
Never wrong. When another engineer told him through a tranlator that a
5 mm nut would not fit on an 8 mm screw, he said that the engineer was
too young to understand, and ordered him to purchase the nut/screw as
ordered. (I ordered some 8 mm nuts without telling him).
We have not won *one single* technical argument with him.
Thinks that we american engineers don't know our own names, or the
phrases "Lazy American" "Stupid Foreigners" or "Inferior Engineers"
in Japanese.
Now don't get me wrong; there are many, many fine Japanese managers.
I usually prefer Japanese management techniques to American ones.
It's just that this particular individual is on the way to making a
bad product and blaming me. I am trying to sway him with experemental
evidence, but I have to do it with my own money and on my own time.
Modem
SA>In article <Pine.GSO.3.95q.970629122331.26798B-100000@earth>, c...@glink.net.
SA>Thank you for taking the time to help me with understanding my
SA>experiment. It's nice to have help from an expert.
SA>>I think the above experiment does not give fully demonstrate your thoery
SA>>as your boss' idea is to have a flowing system so if you design your
SA>>system to eliminate the accumulation of stagnant water you should have low
SA>>risk of microorganism growth.
SA>He has designed in quite a few places where the water doesn't flow,
SA>plus the system may be turned off for many months at a time. I will
SA>set up another experiment with a small teflon pump and see if it makes
SA>a difference.
SA>>As your experiment have stagnant water for a month, I am not surprised
SA>>that that you have fungus growth ( I don't think it is bacteia as you
SA>>probably need a microscope to see bacterial threads).
SA>Fungus! That never occured to me. I was thinking that the threads
SA>were collections of many bacteria, not individual bacteria that are
SA>big enough to see. Maybe I should order a microscope (not that I
SA>would understand what I was seeing)...
SA>>Also another way to eliminate fungus growth is to have a good Quality
SA>>Assurance so to make sure that you eliminate the chances of spore
SA>>contaminaton of the deionised water being fed into the system. (Some sort
SA>>of closed system migt be in order from your deioniser to your tanks)
SA>Is this practical? I assume that even one spore would grow into a
SA>thriving colony. Is it possible to eliminate every single spore?
Could you heat the water to near boiling every now and then to kill the
stuff off?
Ryan Kennedy
Edtec Sales wrote:
> I am the one who will have to fly to Korea or Germany if one of these
> fails, and I believe that the units need some antibacterial measures
> for reliability. I want to incorperate a U.V lamp. My new boss, with
> no education or experience with Deionized Water, has mandated that we
> do no such thing. Yet I will take the blame if it doesn't work...
>
A word of caution with the UV lamp...make sure whatever material you are
using to construct your apparatus will not suffer from any long term
exposure to ultraviolet light. Another caution...test the bacteria
against UV light to see if there is any effect first. For all you know
the bacteria (or fungus) may be relatively resistant to the UV. Perhaps
a better solution to the problem would be to mandate raising the
temperature of the water to a sufficient temperature to either kill the
microorganisms or to force them to form endospores (so long as the
temperature remains high the endospores will stay that way and will be
unable to replicate). This is basically a form of pasteurization and you
should look up some material to find which temperatures and which
durations would be necessary to kill off your particular bacteria or
fungus (whichever it is that you have). A further option (though
probably undesirable since you're using deionized water to begin with)
is to increase or decrease the pH of the water to hostile (to the
microorganisms) levels. This would be an option in case raising the
temperature of the water was not possible or desireable. To me raising
the temperature would be your best bet...however I have no idea what the
capabilities of your system are to withstand a raise in temperature
necessary to destroy the bacteria (generally a raise of temperature to
about 125 C should be enough to kill off most bacteria) nor do I know
exactly what the water is being used for within the system. Knowing
those factors could be very beneficial in determining the propper course
of action.
Ryan Kennedy
Junior Chemistry and Biochemistry Major
California Polytechnic State University, San Luis Obispo
Edtec Sales
In article <33B75ECE...@thegrid.net>, r...@thegrid.net wrote:
>
>Edtec Sales wrote:
>
>> I am the one who will have to fly to Korea or Germany if one of these
>> fails, and I believe that the units need some antibacterial measures
>> for reliability. I want to incorperate a U.V lamp. My new boss, with
>> no education or experience with Deionized Water, has mandated that we
>> do no such thing. Yet I will take the blame if it doesn't work...
>>
>A word of caution with the UV lamp...make sure whatever material you are
>using to construct your apparatus will not suffer from any long term
>exposure to ultraviolet light.
Did that already. 316 Stainless Steel and PTFE Teflon. No problem.
>Another caution...test the bacteria against UV light to see if there
>is any effect first. For all you know the bacteria (or fungus) may be
>relatively resistant to the UV.
I will test this, just like any other design, but I am pretty sure,
based on seeing UV lamps used in many D.I. systems for this purpose,
and the availability of commercial UV units for sterilizing D.I. water.
>A further option (though
>probably undesirable since you're using deionized water to begin with)
>is to increase or decrease the pH of the water to hostile (to the
>microorganisms) levels. This would be an option in case raising the
>temperature of the water was not possible or desireable.
D.I. water, when exposed to the CO2 in air, goes to about 5.5 PH
(CO2 + H2O = Carbonic Acid, D.I. water = little or no buffering),
but I can't add anything to the water.
>Perhaps a better solution to the problem would be to mandate raising the
>temperature of the water to a sufficient temperature to either kill the
>microorganisms or to force them to form endospores (so long as the
>temperature remains high the endospores will stay that way and will be
>unable to replicate). This is basically a form of pasteurization and you
>should look up some material to find which temperatures and which
>durations would be necessary to kill off your particular bacteria or
>fungus (whichever it is that you have).
> To me raising
>the temperature would be your best bet...however I have no idea what the
>capabilities of your system are to withstand a raise in temperature
>necessary to destroy the bacteria (generally a raise of temperature to
>about 125 C should be enough to kill off most bacteria) nor do I know
>exactly what the water is being used for within the system.
I can make a small section of one of the pipes go to 100 degrees C
so that the water passes through a hot zone, but the main tank can't
go above 50 degrees C. Going above 100 would require a pressurized
system (water at 1 atmosphere doesn't exceed 100 degrees C without
turning to steam). Don't some 'bugs' live in 100 degrees C water?
>Knowing those factors could be very beneficial in determining the
>proper course of action.
Here is a system description:
THE PROBLEM:
Various pieces of equipment in semiconductor fabrication facilities
use Deionized water for cooling, then discard the used DI down the
drain. This costs too much. (5-50 cents per gallon).
THE SOLUTION:
A tank full of Deionized water with a recurculating pump to recycle
the water. In the tank is a coil of stainless steel tubing with
ordinary "city" (tap) water flowing through it to cool the D.I. water.
A resistivity sensor tells the system when the tank water is getting
too dirty, at which time more pure D.I. is added and some of the old
water goes out the overflow into the drain. All materials should be
Stainless Steel and plastic or ceramic. (My boss believes brass is
O.K. for D.I. use. He is wrong).
This system must work on a wide variety of equipment, with a wide
variety of D.I. water supplies, in a wide variety of environments.
Like all good products, it must work in a lot of different
applications, and I must clearly specify any applications where it
will not work.
>Ryan Kennedy
>Junior Chemistry and Biochemistry Major
>California Polytechnic State University, San Luis Obispo
Thanks for taking the time to help, Ryan. I am a working engineer
doing the kind of things that you will likely be involved with after
you graduate. From what I can see, you will do well. Offering
intelligent suggestions while asking for more details about the
problem at hand is exactly what I look for when hiring a new grad.
Too many have a "know it all" attitude, or an unwillingness to think
about a problem. You will go far.
Dr. David Rosen
On Sun, 29 Jun 1997, cyc wrote:
>
> As your experiment have stagnant water for a month, I am not surprised
> that that you have fungus growth ( I don't think it is bacteia as you
> probably need a microscope to see bacterial threads).
>
> Regards,
>
> C. Y. Cheung
You are probably right. However, don't both mycobacteria and
actinomycetes form hyphae just like fungi, that occassionally can
be seen with the naked eye?
David Rosen
dro...@arl.mil>
>
>
>
>
Dominique S. Blanc
If you problem is to have a watter quality with a low amont of bacteria,
you face the same problematic that many hospitals which have to produce
desionized watter for hemodialysis or for the preparation of solutions at
the pharmacy. The system we used in our hospital is inverse osmosis
followed by an active choarcal filter and than finally a ultrafiltration
which retain any bacteria. Of course, the system is running all the time
because if you stop it, retrograde contamination of the watter is always
observed after only a few days.
I should add that microorganisms frequently isolated from such pipe watter
are usually bacteria (Pseudomonas, mycobacteria, etc.)
Ryan Kennedy
Edtec Sales wrote:
> I can make a small section of one of the pipes go to 100 degrees C
> so that the water passes through a hot zone, but the main tank can't
> go above 50 degrees C. Going above 100 would require a pressurized
> system (water at 1 atmosphere doesn't exceed 100 degrees C without
> turning to steam). Don't some 'bugs' live in 100 degrees C water?
>
You're going to have to do a little research on your bacteria and find
out what it is to tell if this is going to work. I remember from my
microbiology class (this is all memory right now, I was dumb enough to
sell the book back) that it takes a certain amount of time at or above a
certain temperature to kill off bacteria. Different bacteria require
different temperatures and different durations. So just raising the temp
of a certain section might not be enough since the water may not spend
enough time in the heated state to kill off the bacteria. True, taking
the water above 100 degrees C would mean needing a pressurized system
unless you could find a way to vaporize the water and collect it
elsewhere (this might be a way to further purify the water since the
bacteria will be much more hard pressed to go wherever the vapor will
go). As for bugs living in 100 degree C water, I'm not sure. But 100
degrees will probably kill off most bacteria. Truly the best way to find
out what you should do for temperature raising would be to take some of
the bacteria and do some slide stains and other microbiological tests of
it. Knowing what it is would better tell you what to do (perhaps your
bacteria is particularly susceptible to higher temps and could be killed
off below 100 degrees C or perhaps you could cool the water almost to
freezing and have a similar effect).
The biggest thing for you to do (I think) is to determine just what it
is that you're dealing with though. It could be bacteria, it could be
fungus, or maybe your system has been interacting with itself and
forming some kind of chemical compound which is white and stringy as you
described. Until you know exactly what it is you can't really determine
a course of action. I would take the stuff to some sort of laboratory
which does microbiological work (I have no idea on earth where you would
have this kind of thing done) and have them determine if it is a
bacteria or fungus and if so which one. Perhaps they could also tell you
what kinds of thermal resistance they have as well. Otherwise you'll
just be making a best guess at whatever it is you have in the system and
won't be able to diagnose a cure for it with a high degree of
confidence.
> Thanks for taking the time to help, Ryan. I am a working engineer
> doing the kind of things that you will likely be involved with after
> you graduate. From what I can see, you will do well. Offering
> intelligent suggestions while asking for more details about the
> problem at hand is exactly what I look for when hiring a new grad.
> Too many have a "know it all" attitude, or an unwillingness to think
> about a problem. You will go far.
>
Thankyou, it's reassuring to know that someone in industry thinks that I
have what it takes to survive after graduation. So often students are
plagued worrying if they are going to be prepared for the big time.
Again, thankyou. I hope some of what I've passed along helps you in some
way. I would be curious to know exactly what it is in the water when you
find out.
Carter Fields
I don't know about the mechanics of your water system, but one thing I do
know: As soon as a sterile environment is open to the outside environment
(i.e. air), the once-sterile environment will no longer be sterile. Bacteria
are everywhere. ALthough you may have sterilized your original equipment and
water, the bacteria from the outside environment came in.
------------------------------------------------------
Carter Fields
University of Chicago by day (c-fi...@uchicago.edu)
Northwestern University by night (cfi...@nwu.edu)
Charles A. Abella
Distilled water is not sterile ! Of course any of you said it, but I
disagree on the opinion of C.Y. Cheung that could not be bacteria. In
fact many of the contaminants of distilled water are bacteria of the
genera (among others), Hyphomicrobium or Caulobacter. The metabolism is
aerobic and they grow on C1 organic matter, allways organic
volatiles comming from the surrounding atmosphere. In fact they only
need the water to grow even without organics in there. They are able to
concentrate the dissolved organics coming from the atmosphere with a
very high ratio surface/volume given by filamentous morphologies. Of
course also fungi can do that!.
Best regards
Charles A. Abella
Microbiology Lab
University of Girona
Spain
Edtec Sales
In article <5p9jru$e...@news.acns.nwu.edu>, cfi...@nwu.edu wrote:
>
>I don't know about the mechanics of your water system, but one thing I do
>know: As soon as a sterile environment is open to the outside environment
>(i.e. air), the once-sterile environment will no longer be sterile.
>Bacteria are everywhere. ALthough you may have sterilized your original
>equipment and water, the bacteria from the outside environment came in.
That's what I figure. I am making equipement that:
[1] Has a lid that is sometimes removed.
[2] Has to work no matter what customer buys it
Given this, trying to keep out that first germ is a fools errand.
I am convinced that some sort of biocide (heat, UV, chemicals, etc.)
will be needed.
Of course, a few bacteria won't be enough to clog pipes and foul
pumps, but I see no reaon why the bacteria would stop at a few.
It seems that eventually I will be trying to pump a gelatinious
slime instead of pure water. Noe I have to prove it.
j.r.stephen
Hi Edtec,
Are you sure you can't add ANYTHING to the water? Not even sodium benzoate? At
pH 5.5 a low concentration (millimolar) will have a broad spectrum growth
inhibitory effect. THat is what is used to preserve soft drinks.
Just a suggestion!
John Stephen
Edtec Sales (sale...@edtec.com) wrote:
: In article <33B75ECE...@thegrid.net>, r...@thegrid.net wrote:
: >
: >Edtec Sales wrote:
: >
: >> I am the one who will have to fly to Korea or Germany if one of these
: >> fails, and I believe that the units need some antibacterial measures
: >> for reliability. I want to incorperate a U.V lamp. My new boss, with
: >> no education or experience with Deionized Water, has mandated that we
: >> do no such thing. Yet I will take the blame if it doesn't work...
: >>
: >A word of caution with the UV lamp...make sure whatever material you are
: >using to construct your apparatus will not suffer from any long term
: >exposure to ultraviolet light.
: Did that already. 316 Stainless Steel and PTFE Teflon. No problem.
: >Another caution...test the bacteria against UV light to see if there
: >is any effect first. For all you know the bacteria (or fungus) may be
: >relatively resistant to the UV.
: I will test this, just like any other design, but I am pretty sure,
: based on seeing UV lamps used in many D.I. systems for this purpose,
: and the availability of commercial UV units for sterilizing D.I. water.
: >A further option (though
: >probably undesirable since you're using deionized water to begin with)
: >is to increase or decrease the pH of the water to hostile (to the
: >microorganisms) levels. This would be an option in case raising the
: >temperature of the water was not possible or desireable.
: D.I. water, when exposed to the CO2 in air, goes to about 5.5 PH
: (CO2 + H2O = Carbonic Acid, D.I. water = little or no buffering),
: but I can't add anything to the water.
: >Perhaps a better solution to the problem would be to mandate raising the
: >temperature of the water to a sufficient temperature to either kill the
: >microorganisms or to force them to form endospores (so long as the
: >temperature remains high the endospores will stay that way and will be
: >unable to replicate). This is basically a form of pasteurization and you
: >should look up some material to find which temperatures and which
: >durations would be necessary to kill off your particular bacteria or
: >fungus (whichever it is that you have).
: > To me raising
: >the temperature would be your best bet...however I have no idea what the
: >capabilities of your system are to withstand a raise in temperature
: >necessary to destroy the bacteria (generally a raise of temperature to
: >about 125 C should be enough to kill off most bacteria) nor do I know
: >exactly what the water is being used for within the system.
: I can make a small section of one of the pipes go to 100 degrees C
: so that the water passes through a hot zone, but the main tank can't
: go above 50 degrees C. Going above 100 would require a pressurized
: system (water at 1 atmosphere doesn't exceed 100 degrees C without
: turning to steam). Don't some 'bugs' live in 100 degrees C water?
: >Knowing those factors could be very beneficial in determining the
: >proper course of action.
: Here is a system description:
: THE PROBLEM:
: Various pieces of equipment in semiconductor fabrication facilities
: use Deionized water for cooling, then discard the used DI down the
: drain. This costs too much. (5-50 cents per gallon).
: THE SOLUTION:
: A tank full of Deionized water with a recurculating pump to recycle
: the water. In the tank is a coil of stainless steel tubing with
: ordinary "city" (tap) water flowing through it to cool the D.I. water.
: A resistivity sensor tells the system when the tank water is getting
: too dirty, at which time more pure D.I. is added and some of the old
: water goes out the overflow into the drain. All materials should be
: Stainless Steel and plastic or ceramic. (My boss believes brass is
: O.K. for D.I. use. He is wrong).
: This system must work on a wide variety of equipment, with a wide
: variety of D.I. water supplies, in a wide variety of environments.
: Like all good products, it must work in a lot of different
: applications, and I must clearly specify any applications where it
: will not work.
: >Ryan Kennedy
: >Junior Chemistry and Biochemistry Major
: >California Polytechnic State University, San Luis Obispo
: Thanks for taking the time to help, Ryan. I am a working engineer
Gene Fuss
Edtec Sales wrote:
>
> In article <5pbi7t$j7g$1...@info.abdn.ac.uk>, mbi...@sysc.abdn.ac.uk wrote:
> >
> >Hi Edtec,
> >
> >Are you sure you can't add ANYTHING to the water? Not even sodium benzoate? At
> >pH 5.5 a low concentration (millimolar) will have a broad spectrum growth
> >inhibitory effect. THat is what is used to preserve soft drinks.
> >
> >Just a suggestion!
>
> that they can cool something very hot to 100 degrees C by pumping
> water into cooling passages. Would sodium benzoate collect where the
> water is boiling and clog the pipes? There is a considerable period
> after the part reaches 100 degrees where water flows through, which
> might disolve any buildup...
>
> Thanks for the great idea! I will look into this further.
If you are concerned about residues, you should be concerned about the
dissolved zinc (and some dissolved copper) from the brass fittings.
They'll form carbonate residues at the hot surfaces thanks to dissolved
CO2 and an increasingly acidic environment over time.
Edtec Sales
Thomas Ziegler
On 1 Jul 1997 13:57:40 GMT, sale...@edtec.com (Edtec Sales) wrote:
>...Of course, a few bacteria won't be enough to clog pipes and foul
>pumps, but I see no reaon why the bacteria would stop at a few.
>It seems that eventually I will be trying to pump a gelatinious
If I got all given parameters still in mind correctly:
As you certainly do not have too much nutriciant (DI water) and (as
assumed here: at least rather) clean-tap water then not very much
bio.mass (organismens) is able to grow on it...(but for all
circumstances you could even (optionally) forsee such a (already
proposed) Reverse-Osmosis-Step at the tap water input...
But: Extra steps do mean Extra costs...
So: Keep a lid on the system,avoid new inputs of nutriciants and
contaminants, add the proposed Benzolate and it should work...
(Sorry but maybe your boss in fact isn't that much off?!)
By the way: Copper (from the Brass) suppreses bacterial growth...
charles schroebel
<sympathy with personnel problem: I once had tech supervisor who
wanted me to tell him what the 60hz ripple was sampling at 18/sec
with an a/d. Couldn't build a 60hz tuned tank to rectifier because
it wouldn't be real time. Wanted me to make a reducing flame with
hydrogen as fuel and no oxygen (Yes, I did suggest using Fl as an
oxidizer, just to see what he'd say--nothing). My advice: leave.
Pall Filter corporation makes filters which can stop particles down
to 0.2 micron (claimed), certainly they stop 1u. Takes about three
days to clean up 'clean' DI, then you immediately change thefilter
and resume filtering. You need a prefilter first and then you
draw your really clean DI through the final filter and dump it back
into the resivoir. Don't bump the resivoir or lots and lots of fine
particles (nalgene or polysilicates (if glass) will be released into
the system (particles as just as ubiqitous as ions). How do you know
if the particles are gone (reduced to a tolerable level)? Count them.
One source of counter is Pacific Scientific High Yield Technology.
About 15K will get you started with a laser counter. They're on the
West Coast near Silicon Valley. Pac Sci is a holding company for
two technologies involving laser particle counters: High Yield
(which specializes in vacuum and gas environments) and HIAC/ROYCO
(who do fluids, but who also gave me 45 minutes notice-so it's a
hard thing to recommend them--be careful with HR's claim of counting
under 1u-size (not detect, count). If you're going to have to worry
about sopores and bacteria (darn terminal delay) then you're going
to have to worry about sterilizing. O3 and UV seem good bets. UV
won't introduce particles.
Seriously, find a competitor and bail, it's not worth it (I did it
for five years, not worth it -- why did mgmt hire them???)
Charles B. Schroebel
301 North High Street
Baltimore, MD 21202
(410) 685-5057 x220#
Email: csch...@umabnet.ab.umd.edu
noch ein geht immer noch
charles schroebel
On 3 Jul 1997, Thomas Ziegler wrote:
> On 1 Jul 1997 13:57:40 GMT, sale...@edtec.com (Edtec Sales) wrote:
> >...Of course, a few bacteria won't be enough to clog pipes and foul
> >pumps, but I see no reaon why the bacteria would stop at a few.
> >It seems that eventually I will be trying to pump a gelatinious
> >slime instead of pure water. Noe I have to prove it...
I don't believe it will get to the point where the viscosity is
affected; however, the 'hot' spots will cook the bacteria and you'll
end up with an attached scum which will decrease the heat transfer
rate much as boiler scale does, and thus increase the operating
temperature of the cooled part (unless otherwise controlled).
Sodium Benzoate will also come out of soln if your cooling flow
vaporizes. I don't have the handbook, but I think SB is very
very soluable in hot water.
If you can handle that SB, then maybe you don't need DI. CuSO4
will keep stuff from living and it's blue in aq soln so it's
easy to 'eyeball' and ensure its presence and sufficient concentration.
Maybe CuSO4 and filtering is all you need.
> If I got all given parameters still in mind correctly:
> As you certainly do not have too much nutriciant (DI water) and (as
> assumed here: at least rather) clean-tap water then not very much
> bio.mass (organismens) is able to grow on it...(but for all
> circumstances you could even (optionally) forsee such a (already
> proposed) Reverse-Osmosis-Step at the tap water input...
> But: Extra steps do mean Extra costs...
> So: Keep a lid on the system,avoid new inputs of nutriciants and
> contaminants, add the proposed Benzolate and it should work...
> (Sorry but maybe your boss in fact isn't that much off?!)
> By the way: Copper (from the Brass) suppreses bacterial growth...
>
Yes, but then you have all the insoluables problem when it hits those
hot parts. I worry about the CuSO4 that way, but it's quite soluable
at the conc required to keep life down. And don't mix metals or you'll
get a galvanic coupling you really don't want.
How long does this have to run between services?
How big is it?
Is there down time?
What is the vol/flow required?
What are the cooled parts made of (that are in contact with coolant?)?
What is the price of failure?
Edtec Sales
In article <Pine.SGI.3.95.97070...@umbc10.umbc.edu>,
csc...@gl.umbc.edu wrote:
>How long does this have to run between services?
Years.
>How big is it?
About 0.5 meters (1.5 foot) wide and deep, 1 meter (3 feet) tall.
>Is there down time?
In some cases. no. 24/7 operation. In others (hot standby spare)
it is down 100% of the time until the primary system fails.
>What is the vol/flow required?
10 liters per minute at 35 meters of head.
>What are the cooled parts made of (that are in contact with coolant?)?
Varies. Often 100% 316 Stainless Steel, PTFE Teflon, or Ceramic, but
some customers cool aluminum parts. For those customers I will have
to do testing to see if the idea of a recirculator is even viable.
>What is the price of failure?
About $2000 per hour for the customer. A possible 2 AM wake up
call and 4 am flight for me. :(
Mike O'Hara
Edtec Sales wrote:
>
> In article <5p9jru$e...@news.acns.nwu.edu>, cfi...@nwu.edu wrote:
> >
> >I don't know about the mechanics of your water system, but one thing I do
> >know: As soon as a sterile environment is open to the outside environment
> >(i.e. air), the once-sterile environment will no longer be sterile.
> >Bacteria are everywhere. ALthough you may have sterilized your original
> >equipment and water, the bacteria from the outside environment came in.
>
> That's what I figure. I am making equipement that:
>
> [1] Has a lid that is sometimes removed.
>
> [2] Has to work no matter what customer buys it
>
> Given this, trying to keep out that first germ is a fools errand.
> I am convinced that some sort of biocide (heat, UV, chemicals, etc.)
> will be needed.
>
> pumps, but I see no reaon why the bacteria would stop at a few.
> It seems that eventually I will be trying to pump a gelatinious
> slime instead of pure water. Noe I have to prove it.
I think I remember from a previous post that you could potentially put a
heating element somewhere in the system. if this is so, consider instead
of say a standard heat exchanger putting in a unit that can reach very
high temperatures e.g. 134degC for 5 minutes dwell time would be
adequate to inactivate bacterial spores.
I realize that there are cost of goods implications in this approach,
but if there is a periodic cyling of this UHT sterilizer you won't be
pumping much but water.
Mike O'Hara
WBLanier
(1) I have seen cyanobacteria (photosynthetic bacteria which used to be
called "blue green algae") growing in DI systems upstream of the
bacteriological filter. This was in a system which used clear plastic
filters and holding tanks. Quality Control (QA) of any large-scale water
system is difficult when the systems are run for long periods of time.
(2) For a less anacdotal response, see: Postgate, John (1995) The Outer
Reaches of Life. Cambridge University Press. 276pp in the Canto Editon
(paperback). In particular, see Chapter 10.
Wayne Lanier, PhD
Chris_Gregory
Just a few points of interest.
De ionised water systems are common in many industrys, look at the
existing systems and asses them.
Adding chemicals is not an option unless it is before the de ionisation
stage.
Part of the recirculation stage can be bacteriacidal (kill bacteria)
this would commonly be a UV lamp designed for the task with a suitable
housing and electrical safty consideations. The other option is a
biological filter with pore size <0.5um. This will not make the water
medically sterial as virus particle may remain but it will remove any
bacteria (dead or alive) resulting in particle free water.
once you have one contaminating bacteria/fungi others will soon follow
as food is assimalated into more usable forms.
If you have large storage vessels aim to recirculate them at a high
rate. Two or three times a day throught the filter/UV lamp arangment.
Make the system flexible enought so you can change bits of it.
The bacteria that can grow in such situations are limited but each
change you make may eliminate one while introducing another. Work with
a microbiology company or department. You need feed back on how well
your system is performing.
This sounds like a fun project. Good luck
Chris Gregory
Mike O'Hara
You will find that in most manufacturing firms, certainly pharm and vet
biologics in EU Good Manufacturing Practice compliant companies they
produce the water from clean steam [water for injection] with a very low
total organic carbon. it is held for a validated period of time only.
during the hold time it is maintained at ca 70degC with steam in place
valves taking water from this loop. the whole system is closed and
remains closed. the opportunity for invasion/contamination is very low.
often filtration is not enough - even if you remove the organism, what
sub-micron compunds that it made are left behind?
mike
Charles B. Schroebel
I must apologize for losing my copy of my post re:bgidw; the original
poster had a question concerning just how good di could be if one went
all-out--and I agree taht filtering is not enough for that. It developed,
however, that the application was to cool very clean semiconductor
(silicon crystal?) handlers over very long periods of time with the desire
not to have any down time nor to have to clean the system. If I remember
correctly, the downtime cost was not insignificant.
I apologize to the original writer for not following up on the post. I
believe that the greater concern for your application is not 18 meg water,
but water that is free of insoluable-forming ions (Ca, Fe, CO3 ...) and
free of lifeforms, be they bacteria, fungi, amoeba ... Of greatest
concern would be (to my way of thinking) the avoidance of corrosion cells,
the avoidance of scheduled downtime by multiple filter/sterilizers
(parallel), and automated backup pumps. You're probably going to need
microcontroller based system, and you might as well go to a microprocessor
as the cost difference is not significant. Reliablity is going to be your
greatest concern. Calls in the middle of the night are bad enough, but
$2000/hr is a bit worse.
I think Nalgene would be an acceptable container for your resivoir. I
would make it a dual system so I could clean it if bad things happen
inspite of my best efforts.
Stainless steel, nylon, and PE are probably good enough. If you get
carried away with PTFE, remember that one 7/8::3/4 connector costs ~$100;
a nylon one costs 0.98 and works almost as good except in prolonged
exposure to HCl (among other things). Good enough for water. Good enough
is good enough.
I had exposure experiments run for one year in cells with 1% w/w each of
NaCl, NaSO4, NaCO3 at 60C and had no problems with lifeforms. Cells had
contact with glass, quartz, plexiglass, silicone rubber o-rings (don't
ask), coal tar enamel, air, and the occasional reference electrodes.
good luck,
cbs
Charles B. Schroebel
Box 1205
Baltimore, MD 21203-1205
Mike O'Hara
Charles B. Schroebel wrote:
>
> On Mon, 14 Jul 1997, Mike O'Hara wrote:
>
Good enough for water. Good enough
> is good enough.
>
> I had exposure experiments run for one year in cells with 1% w/w each of
> NaCl, NaSO4, NaCO3 at 60C and had no problems with lifeforms. Cells had
> contact with glass, quartz, plexiglass, silicone rubber o-rings (don't
> ask), coal tar enamel, air, and the occasional reference electrodes.
>
> good luck,
> cbs
>
> Charles B. Schroebel
> Box 1205
> Baltimore, MD 21203-1205
> (410) 685-5057 x220#
>
> Email: csch...@umabnet.ab.umd.edu
I think Charles Schroebel has hit the nail on the head - the key issue
with quality is 'Fitness for Purpose'. what is it your customers really
want? what will they pay extra for? exactly how much do they need?
you may end up with a couple of different 'quality' [read
customer-required] systems built around exactly the same principles but
employing material/methods appropriate to the job.
where regulatory specifications exist you must meet them, but exactly
how is often in your hands.
mike
>
freeto...@gmail.com
RHT
Reiki was discovered in Japan around 1850 by Mikao Usui. It is believed that he was from a wealthy family as he traveled to China and Europe for his education and only the wealthy could afford to do this for their children. This opportunity led him to become secretary to the head of the Department of Health and Welfare. At one point when Usui’s personal and business life was failing he went to Mt. Kurama where he had been before to meditate, hopeful that he would discover the answers to his problems.
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One of the people that Takata Hawayo trained to be a Reiki Master was John Harvey Gray. This name is important as in 1979 he attuned Libby Barnett, who is Shima’s teacher and mentor to Reiki 1 and 2, Reiki Master and Master of Reiki Masters (FYI-Libby attuned me to all three.).
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The Original Reiki Masters initiated by Hawayo Takata
George Araki
Barbara McCullough
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Ursula Baylow (deceased)
Paul Mitchell
Iris Ishikura (deceased)
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Barbara Weber Ray
Ethel Lombardi
Wanja Twan
Virginia Samdahl (deceased)
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Dorothy Baba (deceased)
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Bethel Phaigh (deceased)
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Reiki is also a self-healing modality that has the ability to put the “brakes” on the addiction to adrenalin that most people seem to have today. Rushing through life and trying to cram in as much as we can in a 24 hour period and in doing so leaving behind the connection to ourselves that is so vitally important.
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