Low-Tech Ceramic Water Filter

(wiki.lowtechlab.org)

185 points | by Bluestein 5 days ago

14 comments

  • seer 22 minutes ago
    Hmm just shared this with someone who works in this space in India, they got angry.

    > It doesn’t work for 3rd world contaminants.

    > White people have been making these for years. Doesn’t work

    > We need hard TDS removal also

    And the ceramic ones apparently are also bad:

    > we had one of these for many years while growing up. the ceramic candles got fungus on them

    Viruses are the bigger threat I think and just a filter like this will not stop them HepC and the like would be easily transmittable. Not really “safe”, maybe at best “better than nothing”

    • cassianoleal 13 hours ago
      Ceramic filters are very common in Brazil, used in clay recipients which also keep the water cool even in summer without spending energy.

      https://g1.globo.com/saude/noticia/2026/03/14/filtro-de-barr...

      • smusamashah 1 hour ago
        This sound like Ghara https://en.wikipedia.org/wiki/Ghara which is very common in rural areas in subcontinent. It keeps water cool in summer. It gives water a very nice earthy taste. Ghara is usually paired with a clay bowl to drink water.

        If you can buy a clay bowl or glass, get it and keep water in it on your side and drink from. It will be cool and will have a very nice earthy flavour. But not all clay pots are same quality. Some are not very porous and won't cool the water or give you different taste.

        • lukan 57 minutes ago
          But there is no filter in the Ghara?
        • hliyan 7 hours ago
          Sri Lankan here. We've had this type of ceramic filter here for at least 35 years: https://cdn.shopify.com/s/files/1/0182/4859/7582/files/Ultra...
          • culi 7 hours ago
            Using clay to cool water in the summer is actually the original purpose of olla pots in the Southwest. They cool the water through evaporative cooling

            Andy Ward demonstrated this https://www.youtube.com/watch?v=TBos0j0FszU

            • hdjrudni 5 hours ago
              Doesn't that imply you're losing water?
            • hei-lima 9 hours ago
              Mostly in rural regions, but the 'filtro de barro' water from your grandma's house beats ANY expensive filter you can get, haha!
              • SwtCyber 4 hours ago
                The passive cooling is almost as clever as the filtration
                • weinzierl 11 hours ago
                  This and the low-tech electrical shower-head are the two everyday Brazilian things that never cease to amaze me.
                  • mlinhares 10 hours ago
                    Being poor sucks but at the same time being poor also makes you find alternative solutions to the incredibly expensive solutions first world countries use today. I really wish Brazil can invest heavily into renewables and free itself from oil and electrify even more of everything we do.
                    • m463 8 hours ago
                      > electrical shower-head

                      Is that for electrically heated water?

                      I know that in the US on-demand electric water heater uses an enormous amount of electricity, like 100 amps.

                • ks2048 5 hours ago
                  I'm in Antigua, Guatemala where the embedded video is from. As the video says, it may be "low tech", but it's not like something you can do very easily for yourself. Ecofiltro is everywhere here. But, it is more expensive then I would have thought - maybe $30 for a clay pot and $50 for it's container.
                  • londons_explore 3 hours ago
                    For far less money than that you can buy a regular particle filter...
                  • fastball 13 hours ago
                    There is a company[1] in Indonesia that actually makes very nice versions of this tech.

                    [1] https://www.terrawaterindonesia.com/

                    • 3eb7988a1663 12 hours ago
                      That ad claims it removes microplastics. I was led to believe there are few easy ways to accomplish such a thing. Is this a, "Well technically, we started at 100ug/mL and ended at 99.8ug/mL => reduction!" or is this a meaningful improvement in water quality? The pot looks to just be clay + charcoal + silver - which is not significantly different from other home water filtration systems.
                      • gizmo686 11 hours ago
                        Filtering out microplastics is not particularly difficult. I just checked the first water filter brand that came to mind, and their independent test results [0] reported no detectable microplastics after filtration [1]. Having said that, the linked website above does not inspire much confidence. They have independent lab testing, which is good. However, that testing appears to only cover bacteria; and even their, only two types. Their lab testing also does not indicate any sort of methodology, and it is not clear if the lab was even attempting to test the filter, or if they were just testing the filtered water.

                        [0] Funded by them, and reported on their website

                        [1] Their sample had a known quantity of microplastics, of which they had a 75% detection rate for their control sample.

                        • tlavoie 4 hours ago
                          Does the water end up including some of the colloidal silver? As it happens, there is someone living in my area who has taken colloidal silver in some fashion for ages, with the side effect of turning the skin a ghastly grey hue. I can't say how they're doing for infections and related illness, other than that they probably also have fewer in-person interactions with other people.
                          • Aboutplants 10 hours ago
                            “The pot looks to just be clay + charcoal + silver - which is not significantly different from other home water filtration systems.”

                            Ah, the at home water filtration systems that encapsulated in plastics! Though the benefit of clean water likely makes any potential plastic contamination from the filters moot

                            • PetitPrince 3 hours ago
                              Are microplastic produced predominantly by plastic leaching out of objects, or is it coming from garbage that got mechanically pulverized, UVized, and contaminating water sources ?
                            • fastball 8 hours ago
                              Well the difference is that most home water filtration systems (e.g. Brita et al) are made out of plastic, so even if their filters do reduce microplastic levels, making that claim to consumers ("our plastic filters help reduce plastic in your water") might be a hard sell.
                            • treetalker 12 hours ago
                              From https://www.terrawaterindonesia.com/the-filter:

                              > A single Terra filter purifies up to 42 liters of safe, pure drinking water a day, equivalent of 2 and a half plastic gallons.

                              Someone should tell them to check their math.

                              • ssl-3 12 hours ago
                                Those are plastic gallons. Plastic gallons are similar to treetalker gallons and ssl-3 gallons, in that all of these units share the property of being different compared to US gallons.

                                (The ssl-3 gallon is particularly strange: It isn't even a measure of volume at all.)

                                • SoftTalker 10 hours ago
                                  Heh never heard of a plastic gallon. I was imagining a plastic gallon jug such as a milk jug.
                                  • fastball 10 hours ago
                                    Yeah, in Indonesia (and other parts of the world), the 5-gallon jug you would stick in e.g. a water cooler is called a "water gallon".
                                    • treetalker 10 hours ago
                                      TIL! Not the first time I've made a mistake on account of failing to detect that a different English was being used.
                                      • SoftTalker 10 hours ago
                                        I assume it's a local/informal unit of measure? DDG doesn't know what a "plastic gallon" unit is.
                                        • fastball 10 hours ago
                                          It's not really a unit of measurement but rather just what you'd call the container[1], which in turn is 5 gallon / 19L. But nobody says "My 19L water jug", they they just say "My water gallon".

                                          Since most people in Indonesia get their drinking water from these jugs, stating this filter's output in "gallon" terms is just the easiest way to communicate potential savings etc (since people pay per jug, so they think in jug terms, not in any other unit of measure).

                                          [1] https://m.media-amazon.com/images/I/61fpdmJYUuL.jpg

                                • com 13 hours ago
                                  I may have had an early version of this at home in Indonesia as a kid. Given how close we were to both sea level and the equator, the fact that the water was cool, even when site power failed for days, was bliss!
                                • zahlman 1 hour ago
                                  It took me a while to realize that this is not from "lowtechmagazine".
                                  • Animats 2 hours ago
                                    Nice. It's like a mini version of a slow sand filter.[1]

                                    [1] https://en.wikipedia.org/wiki/Slow_sand_filter

                                    • brador 40 minutes ago
                                      That guidance comic is a disaster. The dirty water is the same color as the clean water.

                                      Very confusing.

                                      • SwtCyber 4 hours ago
                                        There is something very satisfying about sawdust being a feature rather than an impurity
                                        • geokon 8 hours ago
                                          I wonder if you could achieve the same effect more easily/consistently using cement. It's basically how aquifers "filter" water. Limestone is naturally permeable unlike fired clay.. were you need to control the porosity. I'd imagine cement mixtures are much easier to handle and you can make arbitrary shapes (higher surface area and higher hydraulic pressure to increase the flow rate)
                                          • rdtsc 2 hours ago
                                            Cement is not easy to make permeable. With the clay the trick is to put combustible material in the mix which gets burned off and leaves micropores behind.
                                            • SwtCyber 4 hours ago
                                              Maybe, although I think cement would trade one set of manufacturing problems for another
                                            • ChrisMarshallNY 12 hours ago
                                              When I was a kid, we'd go camping, and we had these water filters that you would pump water through, and they would filter it.

                                              It was ceramic, and I think it was the same idea, but we used a pump to force the water through (like a bicycle pump).

                                              • notjes 14 hours ago
                                                Got hackernewsd
                                                • metalman 12 hours ago
                                                  they are not kidding about the "lowtech" or at least slowtech part, hey it loaded! no wonder it was slow, it's reporting about 1990 from 2020
                                                  • rablackburn 3 hours ago
                                                    They probably could have loaded faster if they shipped less than 80mb(!) for a single page
                                                    • Bluestein 57 minutes ago
                                                      That used to be one's entire HDD.- :)
                                                • rainworld 14 hours ago
                                                  • bilsbie 12 hours ago
                                                    [flagged]