A Question For The Hydraulically Inclined And Chemically Clever
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how are the PVC pipes connected? welded? solvent welded? any chance the joins contaminate? you could have the 8.5 sample analyzed. PS: watch out for angry rodents, they are known for creating havoc anywhere. :)
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum
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It could be beavers chewing through the lines and pissing in them (see Christian's post), but the lack of dams in the desert nearby suggests that the cause may lie elsewhere.
Will Rogers never met me.
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Reading the other replies (particularly Elaine's) and starting on the day's caffeine intake, I'd be guessing the dissociation of dissolved carbonates, releasing CO2 and leaving bases behind. Try leaving an "input" sample stand for a day or so and see what it registers. Cheers, Peter [might have to amend my sig - so does Roger's PVC ;P ;P ;P ]
Software rusts. Simon Stephenson, ca 1994.
That's an interesting thought. I'll suggest a round of "day after" testing. Thanks! :-D
Will Rogers never met me.
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dude, try a binary search of the pH levels of the pipes so you know the start value, the end valie - what accessible junctions are in between and what are the pH levels at these places? If gets all lnear etc then i'd guess the pipes are a bad batch EPA approved or not (external leakage excluded) But you might find something else to do with the adhesive or something else interesting? Best start - do the binary search. Hell of an interesting problem to work on though :) Bryce
MCAD --- To paraphrase Fred Dagg - the views expressed in this post are bloody good ones. --
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modified on Wednesday, September 29, 2010 7:17 PM
No one has ever looked at the data before - they've collected it, then tossed the information in the circular file if there was nothing bad apparent. What I'm doing is collating the data and looking for patterns and trends for the first time. I suspect this is the first of many curious things I'm going to discover...
Will Rogers never met me.
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Actually, that shift isn't too great, the pH Scale is logarithmic, but 8.5 is at the edge of what is considered drinkable. If you are really worried, aquarists shops (the ones that sell fish as pets) have a good range of chemical testing kits, not just for pH but other dissolved ions. My main suspicion would be on limescale build-up in the pipes, if you have trouble getting shaving foam to foam that could well be the problem. Could the problem be filters fitted in the houses?
Scale buildup is a problem, but it's not lime - iron and manganese are our main problems in this area. The groundwater is saturated with the stuff. Our testing is quite a bit more sensitive than anything a fish store can offer - lab testing is one of our largest expenses, but well worth the cost for safety reasons. We don't scrimp there, ever! Samples are taken on raw water, btw, before entering any filter system.
Will Rogers never met me.
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Deodorant? :-D
The water in this development is far better than what we have at the office - we aren't served by our own system, being in another company's territory. ;P The water at the office isn't fit to wash toilets in; after running the tap for a few minutes, one of us has to fart, just to clear the air.
Will Rogers never met me.
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It's a long shot, but are you measuring the water from the faucet in the house? Perhaps the mineral buildup in the pipes in the house is causing it (the pipes in the house might be a different material than PVC)? Also, there are water purifiers sold today that also increase the pH of the water. Perhaps each house happens to have one of these? Maybe there is an intermediate processing center (not sure what that might be) that all the water passes through? Maybe the source of the water is not what you think it is (e.g., the water comes from multiple locations)?
Good ideas, but none apply. We know the exact source, have good maps of the installation, and the water is taken from outside taps which no one would apply a filter or treatment system to because of the cost. Inside plumbing might be different - copper, perhaps - but I can't prove it, and it seems unlikely that water taken from 4 randomly chosen homes would show the same pattern. It most likely is something systemic, but it's hard to pin down so far...
Will Rogers never met me.
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Oh. Thought I might have something to contribute under Chemically Clever, but then I realized you were talking about engineering... :doh:
Christopher Duncan
www.PracticalUSA.com
Author of The Career Programmer and Unite the Tribes
Copywriting Services:laugh: I'm always open to suggestions, if you have some good recipes. :-D
Will Rogers never met me.
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I just instituted a formal water testing and tracking program at work and discovered something disturbing that I can't explain. We have a small development built in the past 6 years, comprised of about a half mile square of fairly new homes. All piping is done with new PVC pipe, EPA approved for potable water. We measure the pH at the inlet to the development, and sample it at 4 homes scattered through the neighborhood. At the inlet the pH is consistently 7.18, but when it is tested at the homes it measures 8.5!!! I wasn't the best chemistry student in college, but I passed and understood more than I let on to the teacher. This shouldn't happen in a chemically neutral pipe! That's an awful lot of hydrion getting in there in a very short run. The testers used the same meter at all locations, and the temperature didn't vary by more than a degree F. Today's quiz has one question: what could cause such a large shift in pH?
Will Rogers never met me.
Do you really think plastic is chemically neutral?
Invisible Empire: A New World Order Defined (High Quality 2:14:01)[^] Watch the Fall of the Republic (High Quality 2:24:19)[^] The Truthbox[^]
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Do you really think plastic is chemically neutral?
Invisible Empire: A New World Order Defined (High Quality 2:14:01)[^] Watch the Fall of the Republic (High Quality 2:24:19)[^] The Truthbox[^]
Of course not, but polymerization makes the molecules very reluctant to form new bonds, and most of the organic radicals aren't very polar to start out...
Will Rogers never met me.
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Reading the other replies (particularly Elaine's) and starting on the day's caffeine intake, I'd be guessing the dissociation of dissolved carbonates, releasing CO2 and leaving bases behind. Try leaving an "input" sample stand for a day or so and see what it registers. Cheers, Peter [might have to amend my sig - so does Roger's PVC ;P ;P ;P ]
Software rusts. Simon Stephenson, ca 1994.
5 for that.
Agh! Reality! My Archnemesis![^]
| FoldWithUs! | sighist | WhoIncludes - Analyzing C++ include file hierarchy -
Roger Wright wrote:
That's an awful lot of hydrion getting in there
Let's look at it in context. Assume that what you start with is close to 100% H2O. Adding 3 parts per million (by mole) of a fully dissociated[*1] monoacidic base will give you a pH of 8.5 (pOH of 14.0 - 8.5 = 5.5). You can get big changes in pH around the neutral range adding little amounts of "stuff" to non-buffered water. Changing pH 7 to 8 takes very little more than looking at it, but pH 12 to 13 is equivalent to moving a mountain or two. Having said all that, I have no idea what your contaminant is. My point is that it's not very plentiful. [*1]many inorganic and organic bases will be nearly fully dissocated at 3 ppm. Cheers, Peter ps If we want to take this any further, I might invoke my daughter's Chem PhD! ;P
Software rusts. Simon Stephenson, ca 1994.
This might be caused due to the new pipes, the pipes might get exposed to some chemical during transport. My second guess is that if some kind of chemical is used during pipe fitting... The problem get resolved as the time goes... dont worry....
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Urine
Christian Graus Driven to the arms of OSX by Vista. Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
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Keith Barrow wrote:
Could the problem be filters fitted in the houses?
wouldn't that require one-way valves to be absent or defective? every house is supposed to have one AFAIK. :)
Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] Nil Volentibus Arduum
Please use <PRE> tags for code snippets, they preserve indentation, and improve readability.
Luc Pattyn wrote:
every house is supposed to have one AFAIK.
Not in the UK, we have clean tapwater, it's one of the two things that we get right :-).
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Scale buildup is a problem, but it's not lime - iron and manganese are our main problems in this area. The groundwater is saturated with the stuff. Our testing is quite a bit more sensitive than anything a fish store can offer - lab testing is one of our largest expenses, but well worth the cost for safety reasons. We don't scrimp there, ever! Samples are taken on raw water, btw, before entering any filter system.
Will Rogers never met me.
:doh: apologies, I didn't realise you worked for a company testing this stuff!
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I just instituted a formal water testing and tracking program at work and discovered something disturbing that I can't explain. We have a small development built in the past 6 years, comprised of about a half mile square of fairly new homes. All piping is done with new PVC pipe, EPA approved for potable water. We measure the pH at the inlet to the development, and sample it at 4 homes scattered through the neighborhood. At the inlet the pH is consistently 7.18, but when it is tested at the homes it measures 8.5!!! I wasn't the best chemistry student in college, but I passed and understood more than I let on to the teacher. This shouldn't happen in a chemically neutral pipe! That's an awful lot of hydrion getting in there in a very short run. The testers used the same meter at all locations, and the temperature didn't vary by more than a degree F. Today's quiz has one question: what could cause such a large shift in pH?
Will Rogers never met me.
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Is urine not alkaline? Wouldn't that be why it counters/neutralises the acid from jellyfish stings?
Pete
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Is urine not alkaline? Wouldn't that be why it counters/neutralises the acid from jellyfish stings?
Pete
Maybe this[^] helps :-) from the site: Urban myth states that urine works well against jellyfish stings, and this scenario was demonstrated on a Season 4 episode of the NBC-TV show Friends "The One With the Jellyfish", an early episode of the CBS-TV show Survivor and the documentary film The Real Cancun. At best, it is ineffective and in some cases this treatment may make the injury worse
V.
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Urine
Christian Graus Driven to the arms of OSX by Vista. Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
Christian Graus wrote:
Urine
Good answer. Good answer.
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I just instituted a formal water testing and tracking program at work and discovered something disturbing that I can't explain. We have a small development built in the past 6 years, comprised of about a half mile square of fairly new homes. All piping is done with new PVC pipe, EPA approved for potable water. We measure the pH at the inlet to the development, and sample it at 4 homes scattered through the neighborhood. At the inlet the pH is consistently 7.18, but when it is tested at the homes it measures 8.5!!! I wasn't the best chemistry student in college, but I passed and understood more than I let on to the teacher. This shouldn't happen in a chemically neutral pipe! That's an awful lot of hydrion getting in there in a very short run. The testers used the same meter at all locations, and the temperature didn't vary by more than a degree F. Today's quiz has one question: what could cause such a large shift in pH?
Will Rogers never met me.
Gypsum (CaSO4*2H20). Gypsum is a filler material used in the manufacture of PVC pipe and is an alkali material. Since the PVC piping is new, there is probably some leaching of the filler material exposed on the interior of the pipe. I suspect the pH will rise over time as the leaching declines. Gypsum is also used as a food additive in many foods, especially "Calcium Enriched" foods, and as an additive to soaps and cosmetics, so leaching would probably not be a concern relative to potable water.
modified on Thursday, September 30, 2010 7:51 AM
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Roger Wright wrote:
That's an awful lot of hydrion getting in there
Let's look at it in context. Assume that what you start with is close to 100% H2O. Adding 3 parts per million (by mole) of a fully dissociated[*1] monoacidic base will give you a pH of 8.5 (pOH of 14.0 - 8.5 = 5.5). You can get big changes in pH around the neutral range adding little amounts of "stuff" to non-buffered water. Changing pH 7 to 8 takes very little more than looking at it, but pH 12 to 13 is equivalent to moving a mountain or two. Having said all that, I have no idea what your contaminant is. My point is that it's not very plentiful. [*1]many inorganic and organic bases will be nearly fully dissocated at 3 ppm. Cheers, Peter ps If we want to take this any further, I might invoke my daughter's Chem PhD! ;P
Software rusts. Simon Stephenson, ca 1994.
Sounds to me like you have an open pocket of atmosphere exposion, allowing CO2 in, which would cause this type of alkalinity.
Wikipedia Wrote:
Carbon dioxide is soluble in water, in which it spontaneously interconverts between CO2 and H2CO3 (carbonic acid). The relative concentrations of CO2, H2CO3, and the deprotonated forms HCO−3 (bicarbonate) and CO2−3(carbonate) depend on the pH. In neutral or slightly alkaline water (pH > 6.5), the bicarbonate form predominates (>50%) becoming the most prevalent (>95%) at the pH of seawater, while in very alkaline water (pH > 10.4) the predominant (>50%) form is carbonate. The bicarbonate and carbonate forms are very soluble, such that air-equilibrated ocean water (mildly alkaline with typical pH = 8.2 – 8.5) contains about 120 mg of bicarbonate per liter.
I've had this happen to me on a number of occasions when working with pH sensitive solutions... What is concerning is that it is persistent, because it should decrease over time.. as would any other "contaminants" it seems this is more a structural issue, perhaps a partially crushed supply pipe? or a leaky seal somewhere, that is pulling air, while pushing water. (Negative air pressure inside the pipes, in conjunction with a VERY low pCO2 would cause a CO2 vacuum effect, which would not let water out...)
I'd blame it on the Brain farts.. But let's be honest, it really is more like a Methane factory between my ears some days then it is anything else... -"The conversations he was having with himself were becoming ominous."-.. On the radio...