[HN Gopher] Engineers develop water filtration that permanently ...
       ___________________________________________________________________
        
       Engineers develop water filtration that permanently removes
       "forever chemicals"
        
       Author : benguild
       Score  : 152 points
       Date   : 2023-04-30 17:03 UTC (5 hours ago)
        
 (HTM) web link (www.nbcnews.com)
 (TXT) w3m dump (www.nbcnews.com)
        
       | PaulKeeble wrote:
       | We really ought to show more care and test more when we are
       | creating chemical marvels and new materials. At a certain level
       | of scale a lot of the inventions of the last 50 years turned out
       | to be quite damaging to our health and environment. We don't seem
       | to have the balance right yet comparing freedom to release
       | whatever and complete lockdown until something is proved safe and
       | we keep damaging people and the biodiversity of the planet on
       | which we depend.
        
         | neltnerb wrote:
         | Something that blows my mind is that you can get a patent on a
         | new "state of matter" (implying intrinsically that it has novel
         | properties) but then claim to regulators that it doesn't need
         | new safety testing because it's similar to something existing.
        
         | robcohen wrote:
         | You could make the argument that we really need better methods
         | and technology for determining the health impact of what we put
         | into our environment. The problem as I see it (as a total
         | layman) is that the health sciences are not good at determining
         | the effects of almost anything in the future. The best we can
         | do is wide-scale studies that try to control for different
         | variables (and largely fail, because the set of variables is
         | incredibly large).
         | 
         | I have a feeling we aren't going to solve this problem anytime
         | soon, as the simulations required appear to be so large they
         | are beyond our reach. I am optimistic that we can massively
         | increase the data collected as time goes on, and that will
         | increase our accuracy of studies of things that occurred in the
         | past.
        
           | johnchristopher wrote:
           | Now replace health science with climate science and see how
           | it reads.
           | 
           | https://www.tellerreport.com/life/2021-02-23-%0A---%22the-
           | fa...
           | 
           | edit: documentary might come back on ARTE in the future but
           | in the meantime, if you understand french: https://video.plou
           | d.fr/w/4d35ad9a-6eac-4708-aa62-3b754057407... and
           | https://archive.org/details/la-fabrique-de-lignorance-
           | docume...
           | 
           | It's usually subbed/dubbed in French and German.
        
             | specialist wrote:
             | Cites the documentary "La fabrique de l'ignorance". I could
             | only find a trailer.
             | 
             | https://boutique.arte.tv/detail/la-fabrique-de-lignorance
             | 
             | Please share if you can find the full video. TIA.
        
             | [deleted]
        
             | [deleted]
        
           | thephyber wrote:
           | I would argue there are enough companies that have continued
           | creating these cash cow chemicals even after there was
           | sufficient evidence of substantial harm that additional
           | testing would be useless, except to class action lawsuit
           | plaintiffs to prove what the defendants already know.
           | 
           | Movies that cover this topic: Erin Brockovich, A Civil
           | Action, Dark Waters. More recently the talc powder lawsuit
           | against Johnson & Johnson.
           | 
           | Hell, the Bay Area is littered with EPA Superfund Sites where
           | all of the old chipmakers and their suppliers were. Good luck
           | to Chandler, AZ (where the new American chip fans are being
           | built). I hope you learn at least a little something from the
           | SF peninsula's mistakes of the 1960s-1990s.
           | 
           | A former naval base in my area has been decommissioned for
           | years but still hasn't cleaned up the firefighting chemical
           | runoff that has seeped into the ground. Sometimes there
           | simply isn't a healthier substitute for a chemical or there
           | is no legal method to prevent an organization from screwing
           | up the environment (good luck suing the Navy for something
           | they did 50 years ago before the harm was known).
           | 
           | I would agree that better testing and health trials could
           | have identified these health risks before the companies
           | started using these chemicals, but companies don't have
           | emotions or ethics. They are sociopaths seeking maximum
           | returns and will turn a blind eye (or worse) if their profits
           | are threatened. There is a ton of motivated reasoning within
           | and around companies that produce and use harmful chemicals,
           | especially if they are the only industry in a region.
        
             | scruple wrote:
             | There are multi-million dollar homes and a school facility
             | built on top of (parts of) the EPA Superfund site near the
             | old El Toro MCAS in Irvine. Another set of million dollar
             | homes nearby was built on top of a nursery that was founded
             | in the early 1900s. In both cases, residents are warned not
             | to plant edible fruits or vegetables directly into the
             | soil.
        
           | anonymouskimmer wrote:
           | > is that the health sciences are not good at determining the
           | effects of almost anything in the future
           | 
           | For this particular case I think the real problem is that no
           | one really spent much effort seeing the effects of particular
           | PFOAs in cell culture prior to marketing it. We've had cell
           | culture for over 100 years, so this lack is basically because
           | people either didn't even think about it, or didn't care
           | thanks to dollar signs or greater fear of another threat
           | (household fires).
        
             | mandmandam wrote:
             | I've been hearing about the dangers of Teflon for at least
             | a quarter century.
             | 
             | Lawsuits were being settled in the 9-figure range as far
             | back as 2001 - they kept making it, and actively covered up
             | what they knew, tobacco firm style.
             | 
             | I haven't watched it yet, but 'The Devil We Know'
             | apparently goes in depth on this, with very highly rated
             | reviews. I don't need to be that angry right now though; I
             | know enough about Du Pont for "strong opinions" as it is.
        
               | stephen_g wrote:
               | Teflon itself is safe to use as long as you don't heat it
               | too much (stay well clear of 260degC/500degF) - it's
               | technically a PFAS but polymerised into to molecules that
               | have a high molecular weight so have no biological
               | activity and it is chemically inert. It's the shorter
               | chain PFAS chemicals used in the production process that
               | has caused the huge problems - especially to workers and
               | to people living near the plants (due to groundwater
               | contamination and other environmental release of PFAS)
        
               | bbarnett wrote:
               | _Teflon itself is safe to use as long as you don't heat
               | it too much_
               | 
               | The problem is, people make mistakes. All it takes is a
               | crying child, a burned pot, a mistake in cooking (not
               | thinking about it), and you've hit the wrong temp.
               | 
               | And then the pan is dangerous, leeching, trouble.
               | 
               | The whole thought about the approval was "Well, people
               | can be trusted to not let a pot get too hot! And to know
               | 100% to throw it away if it does!".
               | 
               | Right. Trusted. In a country with warning labels like
               | 'coffee is hot' and 'water is wet'.
               | 
               | Edit: my point is, the above means "teflon isn't safe for
               | home use". Engineers know, also, to have safety
               | tolerances. For something like this, I'd expect the
               | 'danger zone' to be 2x the max possible heat a consumer
               | could apply by accident.
               | 
               | As burners can get crazy hot, that probably means I'd
               | call teflon unsafe, unless it broke down at 2000F.
               | 
               | This is how we can approve things safe or not. Not "trust
               | people will constantly monitor how hot their pan got".
               | 
               | Just as an aside, I was at a hotel the other day, and
               | someone was trying to put buttered toast in the hotel
               | toaster!
        
               | akiselev wrote:
               | _> As burners can get crazy hot, that probably means I 'd
               | call teflon unsafe, unless it broke down at 2000F._
               | 
               | That seems a bit... unrealistic. Not even cast iron is
               | usable at 2000F.
        
               | GavinMcG wrote:
               | No, that's the thing: it's unsafe _unless_ it stays safe
               | to an "unrealistic" range, since people exceed "normal"
               | usage without meaning to.
        
               | elbigbad wrote:
               | Not usable, but doesn't cause forever chems to leach into
               | food or aerosolize.
        
               | anonymouskimmer wrote:
               | I certainly wouldn't have bought that bottle of
               | Scotchguard for my shoes in the late 2000s if it had had
               | a warning label on it.
        
               | Axien wrote:
               | Or scotchguard my entire car.
        
               | myshpa wrote:
               | Or outdoor textiles, or toilet paper, or paper food
               | boxes, or furniture with stain repelents, or cosmetics,
               | or school uniforms, or breast milk, or microwave popcorn
               | bags, or carpet cleaners, or candy wrappers, or pizza
               | boxes, or cattle, or agricultural fields and products, or
               | houshold dust, or water, or firefighting foams, or dental
               | floss, or air ... better to stay away from it all.
               | 
               | https://en.wikipedia.org/wiki/Per-
               | _and_polyfluoroalkyl_subst...
               | 
               | https://en.wikipedia.org/wiki/Perfluorooctanoic_acid
        
               | [deleted]
        
               | clnq wrote:
               | When you're in the mood for some anger towards DuPont,
               | check out "Dark Waters" (2019) too. The cinematography,
               | acting, and pacing are great -- my favourite DuPont rager
               | so far.
        
               | Maursault wrote:
               | _A Civil Action_ , 1998, is not directly about DuPont,
               | though DuPont did manufacture the same chemical that the
               | film concerns itself with, trichloroethylene. Duvall was
               | nominated for best supporting actor for his role in this,
               | and the film was nominated for best cinematography.
        
         | cde-v wrote:
         | Sorry, but more care and testing harm shareholder value.
         | Denied.
        
         | mtsr wrote:
         | Or, you know, not dump millions of liters of waste water with
         | all kinds of chemicals in the rivers at all.
        
         | Tanjreeve wrote:
         | I don't think it'll ever be the case. There's an infinite
         | number of unknowns and unknown unknowns. It's a lot easier in
         | our economic system to solve a bounded problem by throwing
         | money at it than for regulations to be enforced politically on
         | what would be 99% speculative problems.
        
         | dclowd9901 wrote:
         | Because we don't close the loop. We find out asbestos and
         | plastics and whatever else is dangerous actually and then go
         | "ah shit" and that's all. We don't prosecute the makers of it
         | or charge for cleanup. Yeah we have superfunds for
         | breathtakingly poor resource and conservation management, but
         | with micro pollutants don't have the same kind of knee jerk
         | visceral reaction a major radioactive waste site does.
         | 
         | We should have laws that say "if you make something, you own
         | its entire lifecycle, including its safe and ecologically sound
         | disposal." That would turn the page on wasteful production
         | almost overnight.
        
           | ALLTaken wrote:
           | What about the BP Oil Spill? How would that go, reparation
           | and paying someone money like the government isn't going to
           | benefit nobody and especially not the world.
           | 
           | After the Fukushima incident they just dropped the
           | radioactive water back into the ocean. yayy ...radioactive
           | seafood :/
        
         | nonethewiser wrote:
         | Aren't we totally ignoring this with the renewed push for
         | nuclear energy? If we insist nuclear waste can safely be stored
         | than surely we can safely store PFAS.
        
           | Chris2048 wrote:
           | But nuclear waste isn't going to be mass distributed?
        
             | ALLTaken wrote:
             | History tells otherwise. Radioactive toothpaste was once a
             | product...
             | 
             | https://en.wikipedia.org/wiki/Doramad_Radioactive_Toothpast
             | e
        
               | Chris2048 wrote:
               | I said it in current/future tense, why ignore all cotext.
               | 
               | What does 1920s product have to do with a now heavily
               | regulated material?
               | 
               | Also, AFAIK the radium in the toothpaste wasn't waste
               | from a reactor?
        
           | pkaye wrote:
           | We don't use nuclear waste to make non stick pans and water
           | resistant jackets.
        
           | [deleted]
        
           | jdiff wrote:
           | There's a pretty big difference between the two. Nuclear
           | waste is always tracked and treated carefully. PFAS are on
           | store shelves and in homes and in landfills and are entirely
           | untracked. Nothing's being ignored, it's just an entirely
           | differently kind of situation.
        
         | weaksauce wrote:
         | look at the one man environmental hazard that was thomas
         | midgely jr... https://en.wikipedia.org/wiki/Thomas_Midgley_Jr.
         | 
         | one man was so absolutely prolifically bad to the environment.
        
           | ALLTaken wrote:
           | Wow, first time hearing of this.. so terrible.. no money in
           | the world is worth the lasting damages he contributed to.
           | 
           | There are few of such people still alive in the world,
           | without which we'd have millions of less deaths and people
           | left disabled.. Hope someone finds out and the PR stops them
           | from continuing somehow :/
        
           | dclowd9901 wrote:
           | > Kettering was elected as president with Midgley as vice
           | president. However, after two deaths and several cases of
           | lead poisoning at the TEL prototype plant in Dayton, Ohio,
           | the staff at Dayton was said in 1924 to be "depressed to the
           | point of considering giving up the whole tetraethyl lead
           | program". Over the course of the next year, eight more people
           | died at DuPont's plant in Deepwater, New Jersey. ...
           | 
           | > The risks associated with exposure to lead were known at
           | least 150 years before, when Benjamin Franklin wrote about
           | his experiences as a typesetter.
           | 
           | Holy cow. I always chocked up leaded gasoline as one of those
           | "well how could they know" kind of things but people were
           | dropping dead just making it, and Midgley himself was
           | sickened from it by researching its production. Absolutely
           | fucking evil people.
        
             | akiselev wrote:
             | I think we've known about the dangers of lead since Roman
             | times so it's even worse. Quoting Vitruvius [1]:
             | 
             |  _> Water conducted through earthen pipes is more wholesome
             | than that through lead; indeed that conveyed in lead must
             | be injurious, because from it white lead [PbCO3, lead
             | carbonate] is obtained, and this is said to be injurious to
             | the human system. Hence, if what is generated from it is
             | pernicious, there can be no doubt that itself cannot be a
             | wholesome body. This may be verified by observing the
             | workers in lead, who are of a pallid colour; for in casting
             | lead, the fumes from it fixing on the different members,
             | and daily burning them, destroy the vigour of the blood;
             | water should therefore on no account be conducted in leaden
             | pipes if we are desirous that it should be wholesome. That
             | the flavour of that conveyed in earthen pipes is better, is
             | shewn at our daily meals, for all those whose tables are
             | furnished with silver vessels, nevertheless use those made
             | of earth, from the purity of the flavour being preserved in
             | them_
             | 
             | We've known about the danger of the fumes for over two
             | thousand years!
             | 
             | [1] https://penelope.uchicago.edu/~grout/encyclopaedia_roma
             | na/wi...
        
       | gigatexal wrote:
       | science might just save humanity
        
         | Frost1x wrote:
         | I had a chemistry teacher (retired analytic chemist for what's
         | now DOW chemical) in highschool who pointed out something that
         | stuck with me:
         | 
         | We tend to act without consideration and have confidence we can
         | just engineer ourselves out of our mistakes.
         | 
         | I think she was right. While I never try to underestimate
         | humanity's enginuity, there's some arrogance there that we may
         | create problems we can't simply engineer around.
        
           | guywithahat wrote:
           | To be fair though, in the context of humanity we've never
           | encountered a problem we couldn't later engineer ourselves
           | out of. And it seems reasonable to think if we can engineer
           | ourselves into the problem, we can engineer ourselves out of
           | it as well (especially considering the alternative is to say
           | we must stop innovating)
        
             | crazygringo wrote:
             | 1) You're ignoring everyone killed in the interim, from
             | pollution, poisoning, etc.
             | 
             | 2) It's entirely unclear whether we can engineer ourselves
             | out of climate change. We've never experienced anything at
             | this scale before, or from something (fossil fuels) we rely
             | on so much.
             | 
             | The solution to climate change may have to be political
             | rather than engineering, and it may be impossible
             | politically.
        
             | rhaway84773 wrote:
             | > we've never encountered a problem we couldn't later
             | engineer ourselves out of
             | 
             | I think this is survivorship bias. There have been several
             | civilizations which have basically completely died out in
             | human history, who weren't able to engineer themselves out
             | of whatever killed them.
        
               | SoftTalker wrote:
               | True but with technology that had not advanced beyond
               | stone, simple metallurgy, and hand tools. Ultimately
               | limited by whatever power could be extracted from human
               | and animal effort. Once steam power and then electricity
               | were discovered, civilization never looked back.
        
               | fwip wrote:
               | We've only had 200 or so years of widespread steam power
               | (and closer to 100 for electricity). On an
               | anthropological timescale, that's quite short. Egypt was
               | ruled by pharaohs for 3,000 years.
               | 
               | The technology we have is bigger now, and so we're also
               | making bigger problems.
        
             | djbusby wrote:
             | Stopping innovation not the alternative, you're creating a
             | false dichotomy.
        
               | anonymouskimmer wrote:
               | Right. _The_ alternative is to engineer in the solution
               | at the same time you engineer the innovation, so that
               | there 's no problem in the first place.
               | 
               | An ounce of prevention is worth a pound of cure. Do we
               | gain much by requiring innovators of the future to spend
               | their innovation power on solutions to the side-effects
               | of past innovations, instead of brand new innovations?
        
             | bwestergard wrote:
             | There are thousands of species that went extinct due to
             | engineered habitat destruction, pollution, and/or hunting.
             | 
             | We face an ongoing "vulture crisis" in India due to the
             | tremendous use of antibiotics on livestock.
             | 
             | https://en.m.wikipedia.org/wiki/Indian_vulture_crisis
             | 
             | See the book "Their Fate is Our Fate" for more examples of
             | ecological problems affecting humans, for which birds
             | provide early warnings.
             | 
             | Speaking of anti-biotics, we've been so successful in our
             | development and manufacture of these medicines that anti-
             | biotic resistance is a significant and growing problem.
             | 
             | Stepping away from medicine, consider the ongoing water
             | crisis in the Colorado River basin. We engineered our way
             | into vast cities and agricultural projects in the desert
             | (e.g. California's central valley) and there is now no
             | clear path to sustaining all of these projects.
        
             | jmknoll wrote:
             | Sure we have. Climate change, radioactivity, and micro
             | plastics are three _major_ challenges that we have very
             | much engineered ourselves into, and do not appear to be
             | able to engineer ourselves out of.
        
             | htag wrote:
             | We have tons of oopsies that we haven't fixed, and there is
             | no reasonable path towards resolution. It is all a matter
             | of the size of the problem we've created. I agree that we
             | should continue with technological progress, but it's naive
             | to dismiss the risks. Here are some humanity scale problems
             | we've created for ourselves.
             | 
             | * Chernobyl is still unsafe to visit. The amount of
             | radiation we've leaked into the atmosphere and oceans has a
             | measurable negative impact on global health, and often a
             | horrendous impact on local environments.
             | 
             | * Air quality/light pollution/noise pollution is
             | significantly worse than pre-industrial revolution levels.
             | These have measurable negative health impacts.
             | 
             | * We've directly and indirectly caused an uncountable
             | number of extinctions.
             | 
             | * Glaciers are melting at an incredible rate.
        
               | Vecr wrote:
               | For Chernobyl, what do you mean by "unsafe to visit"?
               | Because it's a war zone? I remember a lot of people went
               | in 2019 after the show came out and it was fine. They had
               | a guide or took a dosimeter and weren't crawling over the
               | melted core or anything like that. I don't think the
               | radiation from a nuclear reactor meltdown had global
               | impacts, can you cite something? Even the fallout from a
               | full nuclear exchange at the peak of warhead counts would
               | stay in the northern hemisphere.
        
               | specialist wrote:
               | > _They had a guide or took a dosimeter..._
               | 
               | A perfect vacation resort. Just don't touch anything or
               | disturb the soil.
        
               | htag wrote:
               | Chernobyl safety -> "During the Russian invasion of
               | Ukraine, Russian forces subsequently captured Chernobyl.
               | While there is an increase in radiation in the area, this
               | is due to Russian forces disturbing the soil in the Red
               | Forest and releasing radioactive dust and not from the
               | reactor 4 itself. The New Safe Confinement is reportedly
               | unharmed." https://en.wikipedia.org/wiki/Chernobyl_New_Sa
               | fe_Confinement...
               | 
               | Atmospheric fallout -> "Because all people in the United
               | States who were alive since 1951 received some radiation
               | exposure from fallout, some people may have an increased
               | risk of cancer from this exposure, in particular, thyroid
               | cancer. " https://www.cdc.gov/nceh/radiation/fallout/RF-
               | GWT_home.htm
        
               | specialist wrote:
               | We can't even mitigate relatively banal problems like
               | wild boars and Himalayan black berries.
               | 
               | My go to "oopsie" is the radioactive plume crawling
               | towards the Columbia River. Once that breeches, all
               | settlements downstream will be uninhabitable. Bye bye
               | Portlandia.
        
           | edmundsauto wrote:
           | > We tend to act without consideration and have confidence we
           | can just engineer ourselves out of our mistakes.
           | 
           | Or the people acting without consideration are not impacted
           | by the mistakes and will not be held responsible for
           | engineering their way around them.
        
           | markoman wrote:
           | Having confidence about engineering ourselves out of our
           | mistakes is, after all, the conservative rationale for
           | ignoring Climate Change. They're certain that out of the sky
           | will fall the technology for combating the runaway warming of
           | the earth and it all happen just in time (mind you) before
           | any major harm is visited on the earth's populations.
           | 
           | The actions from the Right that are more directly
           | disingenuous are where they try to deny scientific
           | conclusions and the damage already done. They'll post on
           | twitter (implicit denials of sea level rise by) showing 150
           | year old pictures of seaside landmarks beside today's version
           | with similar sea levels. Yet where are are counter-arguments
           | for why the arctic sea ice/ice shelf is in such worse shape
           | than it was just 30 years ago?
        
             | gigatexal wrote:
             | holy crap -- my pithy comment blew up a bit. I'm really
             | digging the discussion.
             | 
             | Why haven't we seen all the amazing properties of graphene
             | commercialized yet? like super capacitors made from
             | graphene that replace batteries and can insta-charge?
        
       | neurobama wrote:
       | Thermal hydrolysis (raising water/sewage to very high
       | temperatures and pressures) can also break down PFAS and other
       | bad stuff like pharmaceutical compounds. The Washington, D.C.
       | Blue Plains water treatment plant uses this technology to safely
       | convert septic sludge to fertilizer, sold under the brand name
       | Bloom:
       | 
       | https://en.wikipedia.org/wiki/Blue_Plains_Advanced_Wastewate...
       | 
       | https://bloomsoil.com/faqs/#what-is-bloom
       | 
       | edit: As I Google to double-check my recollection, I'm finding
       | mixed but encouraging reports on this technique's effectiveness.
       | For instance this 2021 paper:
       | 
       | https://www.sciencedirect.com/science/article/abs/pii/S22133...
       | 
       | >To our best knowledge, there are only two studies that have
       | evaluated fate of PFAS in sludge before and after HTL. In a
       | report presented by Mitroshkov et al. [19], 15 PFAS were
       | quantified in five sludge samples before HTL. After HTL,
       | concentrations of the majority of these PFAS were below detection
       | limit of the GC/MS/MS. However, the authors did not report the
       | HTL operating conditions used in this study. In addition, PFSAs
       | including PFOS, the commonly recognized most recalcitrant PFAS,
       | were not targeted in this work.
       | 
       | >In another study, degradation of five PFAS (i.e., PFOA, 7:3
       | FTCA, 8:2 FTUCA, 8:2 FTS, PFOS) in sludge by HTL was conducted
       | [35]. Among the five, each spiked at 1000 ug/kg, the first three
       | were degraded > 99% at 350 degC for 90 min. Degradation of 8:2
       | FTS and PFOS was 34% and 67%, respectively. It was found that
       | undegraded PFAS partitioned to the biocrude phase, which may
       | negatively impact the quality and use of these biocrude in the
       | real world.
       | 
       | >Compared to PFAS in water only, more degradation was observed
       | when these PFAS were spiked to sludge. It was speculated that
       | metal ions and mineral solids in the sludge might have
       | contributed to enhanced PFAS degradation [35].
        
       | soperj wrote:
       | Wonder if they also remove carbon nanotubes...
        
       | bilsbie wrote:
       | I never could get a straight answer if the activated charcoal
       | filters can remove these.
       | 
       | I'm distilling my own water now. Seems about the same price as
       | filtering once you factor in the costs of the filters. And you
       | know you're getting everything out.
       | 
       | (I add in my own minerals in case that's important.)
        
         | samtho wrote:
         | Just curious, why not a reverse osmosis setup?
        
         | [deleted]
        
         | lend000 wrote:
         | I don't think distillation actually works for forever
         | chemicals, as they may be miscible to a certain degree or also
         | vaporize and condense. Don't have the source, but there was a
         | story about PFAS in rain recently. Your best bet would be
         | reverse osmosis, which is unfortunately a pretty big waste of
         | water.
        
           | flangola7 wrote:
           | How does reverse osmosis waste water?
        
             | qbrass wrote:
             | You need pressure on the feed side to overcome the osmotic
             | pressure differential between the dirty and clean sides.
             | The dirtier the dirty side gets, the higher pressure you
             | need to move water from the dirty side to the clean side.
             | Eventually you have to flush the dirty side because the
             | concentration of contaminants is too high and nothing will
             | go through the filter even though there's still water that
             | you could use if you could get it through the membrane.
             | 
             | Under-cabinet RO systems are less efficient because they
             | rely on the relatively low-pressure water that's running to
             | the tap and are made to work without electricity.
        
               | stjohnswarts wrote:
               | but do you really care? The "wasted water" is miniscule
               | vs how much people use daily. You fix the 90% problem
               | before you fix the 3% problem, at least that's been SOP
               | in my engineering life.
        
             | delecti wrote:
             | You don't get all the water out that you put in. Currently,
             | very efficient systems output about half the input as pure
             | water, and half as doubly-impure. Less efficient systems
             | are more like 1:2 or worse.
             | 
             | I'm not an expert and can't explain it much beyond that.
             | This summarizes the math better than I probably could:
             | https://en.wikipedia.org/wiki/Reverse_osmosis#Disadvantages
        
             | [deleted]
        
           | bilsbie wrote:
           | Interesting. I can't seem to find any information either way
           | about distillation removing them.
        
         | ars wrote:
         | "Filters containing activated carbon or reverse osmosis
         | membranes have been shown to be effective at removing PFAS from
         | water supplies"
         | 
         | https://www.health.state.mn.us/communities/environment/hazar...
         | 
         | Some carbon filters make the claim on the label, some don't.
         | The only difference is some companies pay to test for it, and
         | then they can make the claim on the labeling, there is no
         | actual difference in the filters.
        
         | nullc wrote:
         | carbon filters remove PFAS but they're relatively ineffective
         | so you need an awful lot of carbon to get a substantial
         | reduction at least compared to the amount needed to remove
         | other things.
         | 
         | RO is effective, as the chemicals in question have fairly high
         | molecular weight.
         | 
         | But then RO is usually used with a bladder tank which will
         | leach plasticizers so ::shrugs:: (they taste awful at least, so
         | the norm is to follow up the tank with RO).
        
       | hgomersall wrote:
       | My understanding is reverse osmosis is pretty good for this for
       | home use. Under-sink RO filters are pretty easy to source and
       | fit.
        
       | justaj wrote:
       | Link to the actual paper:
       | https://www.sciencedirect.com/science/article/abs/pii/S00456...
       | 
       | Link to a better article: https://news.ubc.ca/2023/03/22/new-ubc-
       | water-treatment-zaps-...
        
         | allears wrote:
         | Much thanks for the good links! I hate trashy TV news videos.
        
       | PlasmonOwl wrote:
       | By the way this is ridiculously sensationalised. Would love to
       | see the world rid of nonsense chem journalists. They're operating
       | about 200 ppb at lowest conc. usually we're looking to remove
       | from a 1 ppb. Low quality journal. The issue with PFAS and them
       | bad bois is the accumulation in body. It's already low in the
       | environment and doesn't degrade. So this guy will be all good if
       | we're sitting at 200 ppb in the environment. If we were at that
       | level I reckon we'd be a lot more cancery. Most of top of my
       | head, please check what I say. I'm not an encyclopaedia but I did
       | research in adjacent areas
        
         | twelve40 wrote:
         | if you claim this is sensationalized (ridiculously, too) would
         | you care to decipher what this means:
         | 
         | > They're operating about 200 ppb at lowest conc. usually we're
         | looking to remove from a 1 ppb
         | 
         | who does "they're operating" refer to in this sentence?
        
           | greenie_beans wrote:
           | lol yeah that comment is hard to decipher
        
           | floil wrote:
           | My interpretation: the paper describes a system that works
           | for a starting concentration of 200 parts per billion, or
           | higher. This is unrealistic because, in real world
           | contamination scenario, you would expect to see a starting
           | concentration of around 1 part per billion.
        
           | anonymouskimmer wrote:
           | My best guess is that the GP is referring to the
           | concentration of PFOAs in the test setup. It is possible that
           | a technology that is good at reducing higher concentrations
           | of PFOAs is not good at further reducing PFOAs concentration
           | at lower concentrations.
           | 
           | However, from the link to the paper in another comment (note
           | that this is from the introduction; I don't have permission
           | to view the full paper):
           | 
           | > After finding the best operating condition, the effects of
           | solution parameters such as initial pH, DO, temperature, PFOA
           | concentration, and electrolyte concentration in broad ranges
           | were determined. PFOA concentration and sulfate dosage were
           | chosen to be representative of different aqueous environments
           | (e.g., natural waters and brine solutions).
           | 
           | So I'm not sure where GP gets that this 200 PPB number is the
           | case for all of the tests.
        
       | gibolt wrote:
       | How prevalent are these in water (vs other parts of the
       | environment)? Are there some common places where a few well-
       | placed filters could have an outsized impact in cleaningup our
       | mess?
        
         | empyrrhicist wrote:
         | I think a big source is food, because it's bio-accumulating in
         | our waste, which we spread on fields.
        
       | bertil wrote:
       | I know there was a big scare around PFAS and stick-free pans.
       | That confused me because they are actually on most food-wrapping.
       | Sure, the heat and scraping don't help the pans, but I can't
       | imagine that having it on most things we throw in the trash and
       | then burn or put in a landfill helps much.
       | 
       | > The U.S. Food and Drug Administration (FDA) currently approves
       | more than 90 PFAS in food container materials ranging from paper
       | cups, parchment paper, and microwavable popcorn bags to fast-food
       | wrappers, pizza boxes, and pet food bags, the Interstate
       | Technology Regulatory Council reported in September 2021.
        
         | ALLTaken wrote:
         | Oh my god, I didn't know it's on most food wrapping. So when I
         | get a coffee to go it's also a PFAS that seals the paper from
         | the fluid?
        
           | Teever wrote:
           | And it's on the inside of those shitty new papers straws.
           | 
           | Blows my mind, we've replaced relatively inert pieces of
           | plastic with paper coated in this PFAS stuff and we're acting
           | like it's good for us and the environment.
           | 
           | plastic straws were a rounding error on a rounding error of
           | plastic waste.
        
             | timeon wrote:
             | Straws should be avoided instead of making alternatives.
        
             | SV_BubbleTime wrote:
             | >plastic straws were a rounding error on a rounding error
             | of plastic waste.
             | 
             | Not as a percentage of "outrage". We know who pushes for
             | this stuff, and for some reason they just keep going with
             | it.
             | 
             | I'm pretty convinced things like straw ban are a test to
             | evaluate the demographics of "true believers" out there.
        
       | youniverse wrote:
       | I came across this book Estrogeneration which covers this stuff
       | and more. Haven't read it yet but bottom line he gives this site
       | link where he provides products he has researched and likes. He
       | does recommend a reverse osmosis machine etc.
       | 
       | [1] https://www.amazon.com/Estrogeneration-Estrogenics-Making-
       | Si...
       | 
       | [2] https://www.ajconsultingcompany.com/whatiuse.html
        
         | hombre_fatal wrote:
         | Looks like that book talks about flax seeds and soy which is a
         | red flag for quack territory.
         | 
         | If flax seed and soy are so estrogenic and bad, then let's look
         | at the evidence.
         | 
         | Meta analysis of 41 studies:
         | https://pubmed.ncbi.nlm.nih.gov/33383165/
         | 
         | > Sub-analysis of the data according to isoflavone dose and
         | study duration also showed no effect. This updated and expanded
         | meta-analysis indicates that regardless of dose and study
         | duration, neither soy protein nor isoflavone exposure affects
         | TT, FT, E2 or E1 levels in men.
        
           | vjerancrnjak wrote:
           | What about hops (beer)? I remember beer having magnitudes
           | more than soy or flax seed.
           | 
           | It also turned out that gut bacteria in human keep producing
           | the phytoestrogen from beer days after consumption. [0]
           | 
           | [0]: https://pubmed.ncbi.nlm.nih.gov/15826034/
        
           | cyberpeach wrote:
           | > neither soy protein nor isoflavone exposure affects TT, FT,
           | E2 or E1 levels in men
           | 
           | I'm team science, however, I think it's important to point
           | out that total testosterone and free testosterone are only
           | part of the equation. You also have to look at androgen
           | receptor sensitivity.
           | 
           | From the study you quoted:
           | 
           | > there were insufficient data to evaluate the effects of
           | isoflavone exposure on androgen receptor (AR) expression
           | 
           | More research is needed.
        
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