5 ms·

> Both carbon filters and ultraviolet light are known to decrease chlorine concentrations. Shouldn't the UV light also kill bacteria, though?

k_sze 4y ago
This is the kind of stuff that us laymen (relatively speaking, in the context of microbiology) find puzzling. Another thing I never quite understood was how bacteria thrive in purified water anyway, to the point where they can form biofilm. Where do they even get the necessary nutrients?
- Ekaros 4y ago
  Air maybe? Deposition of dust? Mostly dead particles of skin and so on? Or maybe clothing?
- moremetadata 4y ago
  I've been looking into these home water purification systems. A good one will strip pretty much anything out of the water, so as a window cleaning company that used their own water to clean the glass put it, its dead water, in theory nothing can survive in it. Now to touch and feel that "dead water" it was like handling liquid silk without the thickness or resistance. It would be like having the most luxurious bath or shower you'd ever have without any cleaning products like shower gels, bath soaks etc. It also means the amount of cleaning product used, like washing powder for clothes, shower gels, dishwasher product, goes down and becomes more effective as there is no mineral to interfere with it. Technically pure water is an acid. Anyway I have not found any suitable answer for cleaning the water pipes after these strip everything out of the water filter systems, and whilst it shouldnt be a problem if you have copper pipes throughout the house because copper kills most bacteria and some viruses, hence copper water vessels from the past, if you have the new plastic flexible piping in the house, cleaning will almost certainly be required. Penicillin based antibiotics when they are broken down in the liver become penicillamine and this causes the body to release lots of copper into the blood stream, so how much is that having an antibacterial effect on the body? Plus copper is also needed for interleukin-6 which kills alot of cancer, so if doing lots of penicillin antibiotics, your risk of cancer could go up if your dietary copper intake is not high! Something the medical professionals dont tell you! So something like what the pubs use to flush their pipes leading up from the barrels and kegs should do it for cleaning the water system pipes after the water filter, but like I say, I havent found anything satisfactory from these household water supply filter people. Certainly copper pipes are best though, and if doing some DIY, dont leave any flux on the pipe because in damp cold conditions, condensation reacts with the flux and it causes tiny pinholes to form in the pipe. A good plumber will clean their pipes down to stop this from happening otherwise you get minute water leaks that can get worse very quickly. UV-C is the main disinfecting UV light source, but you dont want to go near it because UV-C destroys pretty much anything which is why most of it is blocked in the upper atmosphere. I know hospitals use it to clean wards and rooms, but it will destroy materials much more quickly, ideally hospitals would clean a ward and room like normal to remove ground on dirt and then use the robots that move around shining UV-C all over the place.
  - jofer 4y ago
    The standard procedure for fixing similar issues with well water is standard household bleach + time to sit + a lot of running water to move everything through, FWIW. Look up instructions for "chlorine shocking well water". You need to calculate the volume/concentration correctly, but there are lots of guidelines to make reasonable estimates of pipe + well volumes. FWIW, the main sanitizer used for kegs is the same thing used in restaurants for the standard "three sink" cleaning system (last dip is in sanitizer). Star San is the main brand name. It's a mild acid and it's both cheap and readily available. It works basically by denaturing proteins, which any acid will do, but the specific one is chosen to be harmless and relatively tasteless as well as easily clinging to surfaces to give extra contact time. I'm not sure it would be a good idea to use it, though, as it might eat away at some plumbing fixtures (e.g. galvanized pipe). If you did, you'd want the non-foaming variety (which is not called star san... Saniclean, I think? Same brand, either way).
  - dylan604 4y ago
    >Technically pure water is an acid. https://finance.yahoo.com/news/insane-golden-chamber-contains-water-080000465.html https://finance.yahoo.com/news/insane-golden-chamber-contain... scroll down to the "Terrifyingly pure water" section for a fun read on how fun really pure water can be.
- DigDugDude 4y ago
  I'm a registered nurse, and while not an expert in microbio, I have more training in it than the average bear. It doesn't take much for bacteria or fungi to start growing on previously filtered water once it's open to air. Just take a glass of filtered water and leave it out for a few weeks. Some glasses won't grow anything. Others will have all sorts of things floating on the surface. Pasteur is credited for formalizing this knowledge when he figured out that if you used a crooked necked flask to store media, it reduces the chance of airborne contamination. Once bacteria form a biofilm, it could make it more difficult for any chlorine or UV light to disinfect or sanitize the surface. The bacteria have formed a sort of protective bubble. Mycobacteria are particularly good at resisting various antibiotics because they have a thicker than average cell envelope. Mycobacterium tuberculosis is another bug in this family.
linuxftw 4y ago
The UV bulbs need to be replaced periodically. This was most likely negligence.
- refurb 4y ago
  Article says the machines were maintained. It doesn't matter if you purify water then expose it to room air. It's going to get contaminated again.
  - lnsru 4y ago
    There was a maintenance record. Not that the machines were maintained. Having visible biofilm I don’t think there was done anything on them.
    - xeromal 4y ago
      This seems a bit of a conspiracy thought. What if the machine was designed poorly or something extraordinary happened causing the film to build.
    - refurb 4y ago
      The machines were operating normally when the investigation was done. Why assume the UV light didn't work and maintenance reports were faked when the easier explanation is the machine was just dirty?
  - linuxftw 4y ago
    The 'machines' may have been maintained, it doesn't mean the filters installed on the waterline before the machines were. Properly functioning UV filters kill bacteria, there would be no way to introduce bacteria into the system from the waterline if the UV filters were working adequately (assuming the upstream carbon filter wasn't acting like a reservoir exceeding the specs of the UV filter also due to lack of maintenance). Since the other machines elsewhere didn't have these filters, it's safe to assume nobody had them on the maintenance list and serviced them.
refurb 4y ago
Sure, but in an ice machine the water is exposed to the air which also carries the bacteria. Ice machines are notoriously filthy because they have tons of tiny spaces that never dry. I remember looking inside an ice machine at work and the inside was covered in a thin film of slime.
zinekeller 4y ago
A friend of mine is technically on a different industry (water for semiconductor use) but he said that UV light is not really that effective, especially if a biofilm has grown. Even if everything works correctly and the setup killed stuff, it doesn't remove their corpses (only filtration can do that). Edit: however it seems that the machines were maintained, so it might not be about this specifically.
- dylan604 4y ago
  great, so a vaccine then? /s
adql 4y ago
Just need one to survive for it to multiply somewhere later down the pipeline. It can also be introduced other way I guess

k_sze 4y ago

This is the kind of stuff that us laymen (relatively speaking, in the context of microbiology) find puzzling. Another thing I never quite understood was how bacteria thrive in purified water anyway, to the point where they can form biofilm. Where do they even get the necessary nutrients?

Ekaros 4y ago
Air maybe? Deposition of dust? Mostly dead particles of skin and so on? Or maybe clothing?
moremetadata 4y ago
I've been looking into these home water purification systems. A good one will strip pretty much anything out of the water, so as a window cleaning company that used their own water to clean the glass put it, its dead water, in theory nothing can survive in it. Now to touch and feel that "dead water" it was like handling liquid silk without the thickness or resistance. It would be like having the most luxurious bath or shower you'd ever have without any cleaning products like shower gels, bath soaks etc. It also means the amount of cleaning product used, like washing powder for clothes, shower gels, dishwasher product, goes down and becomes more effective as there is no mineral to interfere with it. Technically pure water is an acid. Anyway I have not found any suitable answer for cleaning the water pipes after these strip everything out of the water filter systems, and whilst it shouldnt be a problem if you have copper pipes throughout the house because copper kills most bacteria and some viruses, hence copper water vessels from the past, if you have the new plastic flexible piping in the house, cleaning will almost certainly be required. Penicillin based antibiotics when they are broken down in the liver become penicillamine and this causes the body to release lots of copper into the blood stream, so how much is that having an antibacterial effect on the body? Plus copper is also needed for interleukin-6 which kills alot of cancer, so if doing lots of penicillin antibiotics, your risk of cancer could go up if your dietary copper intake is not high! Something the medical professionals dont tell you! So something like what the pubs use to flush their pipes leading up from the barrels and kegs should do it for cleaning the water system pipes after the water filter, but like I say, I havent found anything satisfactory from these household water supply filter people. Certainly copper pipes are best though, and if doing some DIY, dont leave any flux on the pipe because in damp cold conditions, condensation reacts with the flux and it causes tiny pinholes to form in the pipe. A good plumber will clean their pipes down to stop this from happening otherwise you get minute water leaks that can get worse very quickly. UV-C is the main disinfecting UV light source, but you dont want to go near it because UV-C destroys pretty much anything which is why most of it is blocked in the upper atmosphere. I know hospitals use it to clean wards and rooms, but it will destroy materials much more quickly, ideally hospitals would clean a ward and room like normal to remove ground on dirt and then use the robots that move around shining UV-C all over the place.
- jofer 4y ago
  The standard procedure for fixing similar issues with well water is standard household bleach + time to sit + a lot of running water to move everything through, FWIW. Look up instructions for "chlorine shocking well water". You need to calculate the volume/concentration correctly, but there are lots of guidelines to make reasonable estimates of pipe + well volumes. FWIW, the main sanitizer used for kegs is the same thing used in restaurants for the standard "three sink" cleaning system (last dip is in sanitizer). Star San is the main brand name. It's a mild acid and it's both cheap and readily available. It works basically by denaturing proteins, which any acid will do, but the specific one is chosen to be harmless and relatively tasteless as well as easily clinging to surfaces to give extra contact time. I'm not sure it would be a good idea to use it, though, as it might eat away at some plumbing fixtures (e.g. galvanized pipe). If you did, you'd want the non-foaming variety (which is not called star san... Saniclean, I think? Same brand, either way).
- dylan604 4y ago
  >Technically pure water is an acid. https://finance.yahoo.com/news/insane-golden-chamber-contains-water-080000465.html https://finance.yahoo.com/news/insane-golden-chamber-contain... scroll down to the "Terrifyingly pure water" section for a fun read on how fun really pure water can be.
DigDugDude 4y ago
I'm a registered nurse, and while not an expert in microbio, I have more training in it than the average bear. It doesn't take much for bacteria or fungi to start growing on previously filtered water once it's open to air. Just take a glass of filtered water and leave it out for a few weeks. Some glasses won't grow anything. Others will have all sorts of things floating on the surface. Pasteur is credited for formalizing this knowledge when he figured out that if you used a crooked necked flask to store media, it reduces the chance of airborne contamination. Once bacteria form a biofilm, it could make it more difficult for any chlorine or UV light to disinfect or sanitize the surface. The bacteria have formed a sort of protective bubble. Mycobacteria are particularly good at resisting various antibiotics because they have a thicker than average cell envelope. Mycobacterium tuberculosis is another bug in this family.

linuxftw 4y ago

The UV bulbs need to be replaced periodically. This was most likely negligence.

refurb 4y ago
Article says the machines were maintained. It doesn't matter if you purify water then expose it to room air. It's going to get contaminated again.
- lnsru 4y ago
  There was a maintenance record. Not that the machines were maintained. Having visible biofilm I don’t think there was done anything on them.
  - xeromal 4y ago
    This seems a bit of a conspiracy thought. What if the machine was designed poorly or something extraordinary happened causing the film to build.
  - refurb 4y ago
    The machines were operating normally when the investigation was done. Why assume the UV light didn't work and maintenance reports were faked when the easier explanation is the machine was just dirty?
- linuxftw 4y ago
  The 'machines' may have been maintained, it doesn't mean the filters installed on the waterline before the machines were. Properly functioning UV filters kill bacteria, there would be no way to introduce bacteria into the system from the waterline if the UV filters were working adequately (assuming the upstream carbon filter wasn't acting like a reservoir exceeding the specs of the UV filter also due to lack of maintenance). Since the other machines elsewhere didn't have these filters, it's safe to assume nobody had them on the maintenance list and serviced them.

refurb 4y ago

Sure, but in an ice machine the water is exposed to the air which also carries the bacteria. Ice machines are notoriously filthy because they have tons of tiny spaces that never dry. I remember looking inside an ice machine at work and the inside was covered in a thin film of slime.

zinekeller 4y ago

A friend of mine is technically on a different industry (water for semiconductor use) but he said that UV light is not really that effective, especially if a biofilm has grown. Even if everything works correctly and the setup killed stuff, it doesn't remove their corpses (only filtration can do that). Edit: however it seems that the machines were maintained, so it might not be about this specifically.

dylan604 4y ago
great, so a vaccine then? /s

adql 4y ago

Just need one to survive for it to multiply somewhere later down the pipeline. It can also be introduced other way I guess