2982: Water Filtration

Explain xkcd: It's 'cause you're dumb.
Revision as of 13:20, 11 September 2024 by 172.71.134.48 (talk) (removed my last edit as I noticed it was redundant with the following paragraph)
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Water Filtration
You'd think the most expensive part would be the quark-gluon plasma chamber, but it's actually usually the tube to the top of the atmosphere to carry the cosmic rays down.
Title text: You'd think the most expensive part would be the quark-gluon plasma chamber, but it's actually usually the tube to the top of the atmosphere to carry the cosmic rays down.

Explanation

Ambox notice.png This explanation may be incomplete or incorrect: Created by WATER. JUST PLAIN WATER. NOTHING DONE TO IT, JUST PLAIN WATER. POSSIBLY DRINKABLE. - Do NOT drink the water delete this tag too soon.
If you can address this issue, please edit the page! Thanks.

This comic seems to be a diagram of how well water is purified, a common procedure done to make said water safe to drink. However, this well water is "purified" through a series of increasingly unnecessary, expensive, and possibly hazardous steps, ending with producing "pure" water synthesized from hydrogen and oxygen (which have each been synthesized from subatomic particles) - before promptly undoing most of the work by re-adding raw well water, and its original minerals and probiotics (which is one way of describing contaminants and biological pathogens) "for taste and to support immune health".

Step Real Device? Used for water treatment? Explanation
Water softener Real Yes Water softening is the removal of calcium, magnesium, and certain other metal cations in hard water. The resulting soft water requires less soap for the same cleaning effort, as soap is not wasted bonding with calcium ions. Soft water also extends the lifetime of plumbing by reducing or eliminating scale build-up in pipes and fittings. The comic shows the water either being passed through some granulated material (presumably, ion-exchange resins) or into a precipitation chamber for lime (or soda ash) softening.
Reverse osmosis Real Yes Reverse osmosis is a common step used in modern water-purification systems. It relies on using osmotic membranes and high pressures to separate water molecules from dissolved solutes and biological substances. Interestingly, it would also act as a softening step, rendering the previous step potentially redundant, depending on the goals for each step. It's also overkill for most wells, as groundwater often needs treatment targeted to only a few contaminants, if any treatment at all.
Ultraviolet Sterilization Real Yes Ultraviolet sterilization uses UV lamps at short wavelengths to damage the DNA and thereby kill micro-organisms in the water. In the USA, this is an unlikely method of well water sterilization, as the pathogens most likely to be found in well water (as opposed to surface water) are generally much more responsive to chemical disinfection. Many wells don't even need a disinfection step; whether this well needs disinfection or not, this is hardly the most impractical step in this treatment train.
Autoclave Real Yes Autoclaves are essentially large pressure cookers that sterilize items and liquids through exposing them to a high temperature (~120°C or ~248°F) over tens of minutes in presence of water. By maintaining a high pressure, the boiling point of water goes up. This creates a very hot and humid atmosphere, making efficient heat transfer with all contents and inactivating all biological entities through this heat. They are commonly used in hospital and laboratory settings to sterilize plastics, glassware, equipment and solutions (like bottles of growth medium for bacteria) to be used in a sterile environment. The advantage of this method compared to dry heat (aka putting things in a 150°C-180°C oven until they are sterile) is that most lab plastics survive a passage at 120°C without melting. While difficult to streamline (as this technique is used for batches), it has the advantage over light-based methods that heat gets everywhere, and that instead of just damaging DNA, you also denature the proteins and other structures of microorganisms.
Condenser Real Yes This step condenses the steam generated by the autoclave back into water. This is a normal part of the process used in "traditional" water purification by distillation.
Regular osmosis Real No Regular osmosis (also known as "osmosis") is the tendency of a solvent (like water) to flow through a semipermeable membrane towards the side that has a higher concentration of dissolved molecules or ions. It therefore goes from a purer state to a less pure state, the opposite of filtration.
X-Ray Sterilization Real No While x-ray sterilization is used to sterilize equipment, but may also be used as a cold method (in contrast to techniques like pasteurization) of eliminating germs and killing insects in fresh foodstuffs. Has also been used to sterilize postal mail.
Carbon Filter Fake No The water is passed through some volume of carbon - a riff on activated carbon filters, which are used in water filtration as seen later in the process. The exact allotrope of carbon is not mentioned, so this could possibly be a graphite, carbon nanotubes, or even solid diamond "filter".
Neutron Source Real No A neutron source generates high-energy neutrons. High-energy neutrons are highly penetrating and will cause ionization events to occur due to collision with atoms in the water. This can potentially make the water more radioactive due to the generation of radioactive isotopes.
Activated Carbon Filter Real Yes Activated carbon is a form of carbon commonly used to filter contaminants from water and air, as it has a large surface area available to adsorb impurities on its surface. While this isn't a strange step to see in a water purification process, Randall makes a pun here with its proximity to the neutron source - the carbon has been 'activated' by the neutron source, and is currently radioactive. Water filtered through this may pick up radioactive isotopes from the filter.
Gamma Ray Sterilization Real No Similar to x-ray sterilization, this step uses gamma rays to sterilize the water. Gamma rays can potentially irradiate the water through photodisintegration if their energy is higher than the binding energy of oxygen.
Cosmic Ray Sterilization Fake No Similar to the previous step, but this time using high energy cosmic rays to do so. This would be incredibly impractical, as cosmic rays are generally blocked by the atmosphere at high altitudes (as stated in the title text). Furthermore, their extremely high energy (shown to be in the exa-electron volt (EeV, or 1018 eV) range) would cause multiple high-energy particles to be created on impact with the water molecules, irradiating the water significantly.
Electrolysis Real No The water is broken down into hydrogen and oxygen gas using an electric current. Assuming the gas outputs of this process are pure hydrogen and oxygen gas, this *would* be an extremely effective sterilization tactic, seeing as no known organism or water pollutant is entirely composed out of hydrogen or oxygen gas. Along with the next step, this step may be a misguided attempt to "take the water apart and clean each part individually". The hydrogen is sent to the ionizer, while the oxygen is sent to the oxygen spallation step.
Oxygen Spallation Fake No Almost all oxygen in existence was originally created via stellar nucleosynthesis. Now, in this step in the purification, the oxygen is apparently broken down back into hydrogen via a fictional form of spallation. While spallation can form lighter nuclei from heavier ones, there is no known process to convert oxygen back down to hydrogen. It is unclear what happens to the neutrons present in the oxygen nuclei - whether they are removed, used to create hydrogen isotopes or allowed to decay into protons and electrons (the components of yet more hydrogen, when properly reintroduced). The hydrogen formed here is merged with the rest of the hydrogen before being sent to the ionizer.
Ionizer Real No The hydrogen output by the previous step is made into a plasma with free electrons and protons (not bound into atoms).
Quark-Gluon Plasma Chamber Fake No The plasma output from the previous step is further energized into a quark–gluon plasma, such as the one found just after the Big Bang. This follows the theme of the previous steps, which all serve to break the water down into their elementary components. The incredible energies involved in doing so are unachievable by current technologies (current particle accelerators can form such a plasma for very short periods of time and involve a very small amount of matter), and serve to highlight the impracticality of this setup (as alluded to in the title text). The energies would also result in formation of lepton pairs from energy, which is presumably where the electrons from the previous step ended up.
Hydrogenation Kinda No This process converts the quark-gluon plasma output in the previous step into elemental hydrogen, reversing the previous two steps. Presumably, this is done via hadronization and recombination; however, it is unclear how the baryon asymmetry needed to generate matter and not anti-matter is developed. The resulting hydrogen is split into 2 streams leading into the Nucleosynthesis and Reverse Electrolysis steps. In real life, hydrogenation is the process of adding hydrogen to unsaturated hydrocarbons.
Nucleosynthesis Fake No Part of the hydrogen produced in the previous step is converted into oxygen via 2 sub-processes. The hydrogen is first converted into helium and carbon through a combination of the proton-proton chain and the CNO cycle as per the labels on the step. The helium and carbon are then converted into oxygen through the alpha process. This step may also involve the triple-alpha process, seeing that the alpha process is typically only applicable to converting carbon into heavier elements owing to the lack of a stable element with eight nucleons. These steps normally occur in the cores of massive stars. It is not known how the oxygen is filtered from the extremely hot plasma of fusion products.
Reverse Electrolysis Real No This step is essentially a fuel cell, utilizing an electrochemical reaction to convert hydrogen and oxygen back into water and electricity.
Adding Well Water Real Yes A second pipe is linked to the first that simply feeds untreated well water into the pipes, partially undoing the entire process. Even if the well water is only a small portion of the faucet water, its presence has now made the now incredibly pure water impure. This act of putting well water into the faucet after treating it may be a riff on the cultural interest in "spring water" or "pure glacial water" that is said to have additional minerals or beneficial properties but is oftentimes not meaningfully distinct from properly treated tap water. "Local minerals and probiotics added" may be a reference to Coke's "Dasani" brand drinking water, which is purified by reverse osmosis, and then has a package of minerals added to create the flavor (pure water's actual lack of flavor can be perceived as an unpleasantly 'flat' flavor).

In addition, drinking only extremely hypotonic liquid intake can induce the body to expel more water than it took in (taking with it some essential minerals that are not being replaced) to try to maintain equilibrium of concentrations. This effect is not directly dangerous, but could exacerbate other bodily deficiencies in the long term and have the issues of greater than necessary liquid throughput than with 'normal' drinking water. The tendency for many 'sports' or 'health' drinks to hype the term 'isotonic' is based upon the idea that an ideal concentration of solutes can be added, in-between the opposing problems of having either too many or too few 'impurities'. The process does not include adding untreated (and probably also untested/unquantified) ground water, which could carry pathogenic organisms and chemicals, and appears to have no mechanism for ensuring what might be an acceptable level of re-blending for the circumstances.

Alternatively, it may be that the level of purity achieved by this setup is so overkill, and the cost per liter processed so high, that it's simply more efficient to treat just enough of the water to dilute the rest of the water to acceptable levels of contaminants. For example, it's common to use a partial bypass to supply water to the shower, since shower water does not need to be potable. Also, some well water systems are clean enough to not need any treatment at all and can be used straight from the well, and some water systems are only slightly high in a single chemical contaminant that can be addressed by blending the water, either with treated water or another source (treated or untreated). Perhaps the treatment process led to enough radioactivity that blending with the original source was required to address radiological contamination (either gross alpha radiation or specific radionuclides).

The title text briefly covers the cost implications of the components. Various 'real' filter elements will have material or energy costs or both, in operation or to replenish their effectiveness, and the high energy input needed to disassociate hadrons into raw quark–gluon plasma (at bulk levels) would seem to require the most in terms of running the equipment. But it is pointed out that to ensure enough cosmic rays reach that particular phase of sterilization, there would have to be a pipe (not shown) leading out to the edge of the atmosphere to optimistically carry down such particles (due to also containing no air, i.e., keeping it out to negate the normal shielding and dissipating effect of the atmosphere on cosmic rays).

Whether a one-off cost or needing regular replacement, the setting up of such a tubular structure (a vertical air-proof pipe perhaps somewhere between 100 and 10000 kilometers high) would be technically challenging and has not ever been actually accomplished. The conditions for a quark–gluon plasma, albeit in limited quantities, at least have been fulfilled at CERN, with its 27 kilometer airless pipe that goes round within a vast circular tunnel.

Transcript

Ambox notice.png This transcript is incomplete. Please help editing it! Thanks.
[Header:]
How Water Filtration Works
[A system of various devices between water pipes is shown.]
[Input:]
Well water
[Labels of various devices:]
Water softener
Reverse osmosis
Ultraviolet sterilization
Autoclave
Condenser
Regular osmosis
X-ray sterilization
Carbon filter
Neutron source
Activated carbon filter
Gamma ray sterilization
Cosmic ray sterilization [On the device: "EeV γ"]
Electrolysis [H2O split into O and H]
Oxygen spallation [O becomes H]
Ionizer [H split into + and -]
Quark-gluon plasma chamber [+ and - become QGP]
Hydrogenation [QGP becomes H]
Nucleosynthesis [H goes through "P-P CNO" and becomes He and C, then through "Alpha" and becomes O]
Reverse electrolysis
[Output after devices:]
Pure water
[Second input, mixed with pure water:]
Well water
[Label:]
Local minerals and probiotics added for taste and to support immune health
[Final output:]
To faucet


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Discussion

On the activated carbon filter, that's a double entendre, referencing both activated charcoal filters often used in filtration systems and the nearby neutron source, which is radioactivity activating the carbon. 172.71.254.23 04:32, 7 September 2024 (UTC)Corsac

There are a bunch of processes shown that are real, but not actually used in water filtration. For example, electrolysis is used to make hydrogen and oxygen gas, and reverse electrolysis is used in fuel cells to produce electricity, but the electricity cost of doing these steps to purify a useful amount of water would be prohibitive. 162.158.159.14 06:18, 7 September 2024 (UTC)

On the other hand, it would be a kind of "extra-intense distillation". We already basically have been "distilling water", as I see it, with the autoclave/condenser pairing that would certainly leave any remaining dissolved minerals or particulates behind. By splitting then recombining the component elements (and some basic gas-chromatography process, not shown) then you'd inarguably get water out that's about as pure as you can hope for in even the most paranoid fantasies about the need for clean water.
...of course, here it's not even the most energetic attempt to further 'refine' the components of "watery matter", with the assumed luxury of having energy (and indeed water) to burn... 172.69.194.219 06:39, 7 September 2024 (UTC)
Yes; I'm wondering if we should be a bit more specific than just "real" vs. "fake". Some of the processes would work, but wouldn't make the water purer; some are impractical but feasible; some aren't possible at all. BunsenH (talk) 16:10, 7 September 2024 (UTC)

Regarding condensers: Condensers are a real method of purifying water, although perhaps not commonly used to demineralize household well water. I frequently buy "purified" water that has been distilled which is simply boiling the water and then condensing the steam into pure water. This is great for use in tea pots or egg cookers or humidifiers to avoid mineral buildup inside the pots. Rtanenbaum (talk) 14:35, 7 September 2024 (UTC)

Regarding adding the well-water back in at the end: "Purified" water is often sold in the baby aisle for use in mixing baby formula, but the labels indicate that minerals have been readded to the water, which of course means it is no longer pure, and would not be useful if I want to avoid mineral buildup in a tea pot. Rtanenbaum (talk) 14:35, 7 September 2024 (UTC)

This comic made me realize how to fund space exploration: selling "artisinal space water" to gullib- I mean, discerning rich people. 172.69.246.151 15:48, 7 September 2024 (UTC)

I have silt, iron, manganese, and microbes in my well.

In a real life, the first step will be mechanical filters: frog-screens, leaf nets, sand or paper media. In my well-water this takes most of the yuck out (as brown sludge).

Home-scale UV treatment is commonly sold (and apparently used; spares available) for spot-treating rural well water. Industrial UV exists for very expensive 'pure water' which must not make anybody sick. ALL water gets germs; UV may have less side-effect than Chlorine or Bromine.

Condensing (and distilling!) are standard household appliances for DIY distilled water. 'Activated' Carbon elements are VERY widely sold for taking taste/smell out of tap water.

"Water softening" (several types) is bog-standard technology out beyond the city mains. (PRR (talk) 19:08, 7 September 2024 (UTC) ...cntd below)

Please sign your comments. And yes, it is. But not immediately before filtering by reverse osmosis. Reverse osmosis should remove almost all solutes, so the resulting pH should be very close to 0 and the concentration of no chemical except water should be significant. Water softening before or after is unnecessary. Don't get me wrong; RO is not perfect. But water softening is only ever necessary to remove large amounts of minerals that can leave scale, and that isn't an issue with high-purity water. EebstertheGreat (talk) 08:03, 8 September 2024 (UTC)
NB, the comment was signed, if you check. This was fifth of sixth straight 'level zero indented' comments. Personally, if I'm not replying (sitting after any number of ":"s, per line) I prefer to add a <br>-tag to force the linefeed (that isn't rendered, otherwise), rather than make it double-LF and potentially look like separate contributors.
It also helps if it's written to look like it's the same contributor (disjointed paragraphs switch narratives seemingly at random don't help... especially), but it isn't foolproof (and unsigned+signed contributions can look like one slightly rambling contributor, hence why signing does need to be added wherever necesary).
But it's all in the eye of the beholder, some of whom may be the posters concerned and be absolutely sure that the future confusion won't exist. And sometimes (very occasionally), there'll be a wish to interleave a comment specifically against an 'inner paragraph' of the wider message you're replying to. You can perhaps copy the 'official' signature of the original flow, like I did here. Can get messy any which way, of course.
Some people might even think it better to (at least in non-reply additions, zero-coloned) just stick to one long rambling no-break paragraph. But I usually find that inelegent both in reading the Talk page and in its edit-source. Being terse and to the point perhaps helps, though, if possible. Not that I'm good at being laconic, as you can see! 172.70.163.48 11:35, 8 September 2024 (UTC)

Of the radioactive treatments, Radon is not mentioned; surely this kills a few germs? PRR (talk) 19:08, 7 September 2024 (UTC)

Using radon would be a bad idea. Even if one got all of the radon out afterwards (e.g. by sparging), it would leave behind radioactive daughter products, as well as the lead at the end of the decay sequences. Granted, radium-enriched water was a commercial product, back in the day, but... still a bad idea. BunsenH (talk) 21:58, 7 September 2024 (UTC)
Yeah, the philosophy tended to be "if it fluoresces, it impresses!", in the pseudoscientific quackery of the time... 172.69.79.183 23:15, 7 September 2024 (UTC)
Wait ... you have filters which turn frogs to brown sludge? Is that legal? -- Hkmaly (talk) 05:24, 8 September 2024 (UTC)

So much that I didn't notice in my first forty minutes looking at the comic while thinking "uhmm wut no! ! !" Y'all are why I come here especially when I think I thought I understood it and didn't need it explained. BTW? Are some for which the explain cannot be complete. The user interactive recent one with squirrels, fans, balls and things that made it kinda a pinball game but most assuredly not (mostly) come to mind. Thank you all. (Edited for clarity}172.70.43.54 04:19, 8 September 2024 (UTC) 172.70.39.34 04:28, 8 September 2024 (UTC)

Are we talking about water treatment, water filtration, or water purification? Because blending water and using UV are useful tools in water treatment but are not filtration and are pointless for purification. Treatment is anything done to make the water healthier or more pleasant to drink or better for equipment. Filtration requires physical separation of water from contaminants (which would not count most of these processes, and some, such as electrolysis, kinda break the definition water systems use since they separate at too fine a level to really count as a water filter anymore, despite the comic name). Purification is the elimination of anything that isn't water. I thought part of the joke was that it was supposed to be treatment for home faucets for drinking purposes. I wouldn't care except it would change the classifcation of the columns. 172.70.178.122 10:49, 8 September 2024 (UTC)

Some references on how hypotonic water doesn't harm human beings: https://www.medicinenet.com/is_drinking_distilled_water_good_or_bad_for_you/article.htm https://www.medicalnewstoday.com/articles/317698#is-it-safe Nitpicking (talk) 12:58, 8 September 2024 (UTC)

There's degrees of harm. Generally agreed that the danger isn't anywhere as bad as the 'scare stories'. (As per edit-comments, you don't explode from osmotic pressure by trying even a squirt of the ultrapure water sat around in school chemistry labs, but it probably saved having to resupply so much if incautious pupils didn't glug it down constantly.)
For example, https://www.webmd.com/diet/distilled-water-overview certainly says that it's safe, but still does point out that...
Distilled water lacks even electrolytes like potassium and other minerals your body needs. So you may miss out on a bit of these micronutrients if you drink only the distilled stuff.
Some studies have found a link between drinking water low in calcium and magnesium and tiredness, muscle cramps, weakness, and heart disease. Also, distilled water may not help you stay hydrated as well as other kinds of water.
...and this is reflected in many of the respectable "is it safe/dangerous?" articles. (The medicinenet link you give actually goes into more detail on these points. Don't know about medicalnewstoday, as I can't even easily get past its "privacy notice" 'cookiewall', the way it's configured.) Thus if we're discussing why we're adding this at all (and end up with "isotonic" being a buzzword, because it sounds better than "flavoured sugar water with some mineral salts"), I had tried to explain why it could be thought necessary to proportionately undo basically the prior (often unnecessary/improbable) purification process. Couched in terms (I imagined) would not promote the "your body asplode!" myth, either. 172.70.91.90 13:33, 8 September 2024 (UTC)
I don't feel like an edit war, but in fact ions are not lost, period. The gut actively transports ions in, the osmotic pressure difference is nowhere near enough to remove ions that way. You don't get the ions in tap water, but they aren't actually nutritionally significant for essentially anyone.Nitpicking (talk) 01:54, 9 September 2024 (UTC)
I don't think you're arguing about quite the same thing, if you want my opinion. But - unlike you lot - I'll not expand huge paragraphs on this issue. 172.70.91.201 10:29, 9 September 2024 (UTC)
You may lose more ions in mouth than in gut. Nevertheless, it's not dangerous amount, and while ions in tap water can be handy and may allow you to survive longer without eating (especially when sweating), if you eat normally, balanced diet, you get much more nutrients in food than in water. -- Hkmaly (talk) 22:35, 11 September 2024 (UTC)

"It is unclear what happens to the neutrons present in the oxygen nuclei" They're used in the Neutron Source. Vkapadia (talk) 20:01, 11 September 2024 (UTC)