Hackaday Prize Entry: Collaborative Water Purification

Look over any description of a water treatment plant, and you’ll find a description that includes the words, ‘coagulation tanks’. What are these treatment plants coagulating? You don’t want to know. How are they doing it? With chemicals and minerals. Obviously, there’s something else that can be done.

For their Hackaday Prize entry, [Ryan], [designbybeck], [Clint], [Wanda] and [Maker Mark] are investigating electrocoagulation. It’s an alternative to a frothy brew of chemicals that uses electricity to pull pollutants out of the water.

Right now, the tests are much smaller in scale than the tens of thousands of gallons you’d find at a water treatment plant. In fact, the test rig is only a 16-ounce mason jar. While this isn’t large enough to precipitate pollutants out of a household water supply, it is big enough for a proof of concept.

The team is using two electrodes for this build, one aluminum, and one iron. These electrodes are connected via alligator leads to the electronics board they’ve built. This electronics board is basically just an H-Bridge (used so they can reverse the polarity of the field emitter and prevent a buildup of gunk on the electrodes) and a few connectors to a power supply. The results are encouraging; they have a few time-lapse videos of a mason jar of dirty water clearing up with the power of electricity. It’s a great project with some great documentation. The team already has a bunch of updates on their project and instructions on how to replicate their hardware. You can check out those videos below.

63 thoughts on “Hackaday Prize Entry: Collaborative Water Purification

    1. It also doesn’t seem to do anything for microbial, fungal or other biological contamination? What about heavy metals? Non conductive contaminants? It might be useful as one step in a process but merely turning water from “something in it” to “clearish” does not mean it is rendering the water potable, especially if it is extremely reliant on the contaminant(s) being only a certain material. Still, this is interesting but more details are needed to better evaluate this.

      1. Electrofloculation kills almost all microbial life. It creates cations and anions that quite literally tear cells apart at the seams. As for as Heavy Metals that is the where the most promising research is being done concerning electrofloculation where there are getting removal rates using this process of 99% and higher for some metals (I can’t find the specific source I am looking for but this is similar and in reference to use in Mining waste. http://www.itrcweb.org/miningwaste-guidance/to_electrocoagulation.htm

    1. Dunno, but the guy is driving around talking to a camera instead of focusing on driving a 2 ton vehicle.

      Video bloggers are already the salt of the earth – this sort of garbage is radioactive salt of the earth. I can’t stand people who “vlog” while driving – studies have shown talking on a hands-free phone is distracting. This is equally bad, maybe even worse.

  1. Now, be careful here. They left out the fact that it is currently used mainly as a /wastewater/ treatment method – it’s potentially a little dangerously misleading to call it a “water purification” method. AFTER filtration, the water is clean enough to dump out, but it’s unclear whether or not you’d want to drink that water without more testing, as this method will not just generally remove every harmful pollutant from wastewater. It looks like there’s some dependence on electrode material and pollutants removed, etc.

    It’s a great first pass method for wastewater from many processes, though, which is why the results are so shockingly visible – but it’s what you can’t see which is often still quite harmful.

          1. In case that wasn’t clear, that was a joke. It would depend on what the sludge was exactly and this isn’t a cure all water purification process anyway.

        1. This is a good question though. So maybe you can separate something bad from water now it’s not only bad but concentrated what do you do with it? It all depends on what you’re working with. In some water processes they actually take the waste and run it through a filter press to squeeze all the excess water our and turn it into solid waste. You have to know what you’re working with to know if its toxic and needs to be disposed of correctly. Sometimes you can take and reuse parts of that waste. Sometimes yes you can just send it down the drain. All depends.

          1. If it is anything like ‘Time Bandits’ where one had to avoid pure, concentrated evil then I would offer the suggestion that one should employ a handful of midgets to help make light of the situation.

        2. Same as with normal wastewater treatment plants, it gets piled somewhere and eventually is dealt with as dangerous waste…
          Nothing else you really can do, anything coming from sewers will be rich in all kinds of bad things, starting with bacteria, going through heavy metals and ending with organic-but-not-alive stuff (drugs of all kinds)…

      1. UV is only good if the dose is adequate for the flow rate and even then only good for microbial types of contamination. Isn’t going to do much of anything if you had, say, mercury or PCBs in your water.

        1. But I’ve seen UV LEDs on hand driers in washrooms! Surely they sanitise my hands? They must be really good, since the light of one or two LEDs seem to be enough.

    1. I agree the title isn’t accurate for electrocoagulation alone. Our overall goal is to see where this could fit in DIY purification as a whole and to learn about other open source diy water processes out there. We do this collaboratively with students, hackerspaces, citizen scientists etc and share our findings on here now that we’re on hackaday and through videos on youtube.

      1. Hey dude: put the camera away and drive, yeah? There are people on the road who aren’t protected and if you hit them, you could seriously injure or kill them.

        Despite what you may think, your time isn’t nearly so precious that you can’t record a video like this sitting at your workbench. Or, you know, write it up so the rest of us don’t have to suffer through three and a half minutes of video just to get the same info in a few paragraphs of text.

        1. +1
          Also, my time is valuable enough that I don’t want to watch him eating while driving.

          Of course, OP is such an amazing driver that he would never crash due to being distracted by filming an overpass instead of steering. That only happens to OTHER people, you see.

  2. This is how they used to sell water purification systems door to door. Test your tap water, oh no look at all that yucky sludge! Test our purified water, no sludge! Most of the mineral precipitates were fine and/or beneficial but oh well.

    1. Most of the mineral precipitates shown in this “test” do not come from the water.
      This is just a crude conductivity check. Normal Tap water contains enough minerals (normally mostly healthy or harmless) to be conductive. Therefore the iron anode electrolytically dissolves with the applied rectified mains voltage and forms brown sludge in the water (iron oxides and hydroxides) which is presented to the naive customer as indication of coagulated contaminants.
      If you have your water purified with the advertised apparatus (ion exchange and reverse osmosis) you have deionized water which is not conductive any more and therefore the iron does not dissolve and the water stays clear.

      Even if electrocoagulation can work under some special circumstances, this has nothing to do with it.

  3. Thank you for making this open source. My son is considering water filtering techniques as a science project for next year, and this would go very well with that theme.

    One thought, have you tried the clarifiers used in swimming pools in conjunction with your method?

      1. No, I meant using the clarifier polymers to bind the contaminants in larger clumps. Not use the water from a pool.

        The amount of chlorine in water from a pool would not cause a large amount of chlorine gas, and would likely not be toxic. Concentrations are 1ppm to 3ppm when used in pools and spas.

      2. Ordinary chlorination wouldn’t be a problem. An area I lived at for most of my life is far from ordinary in this regard. So high that without some sort of filter you will get a headache drinking the water but thankfully nothing more severe than that. When I was working on producing hydrogen to run a modified lawnmower engine on, one problem I ran into was opening my electrolysis jars after they had burned through most of the water. Every time I would open one I got a whiff of chlorine and light headed. Thankfully I gave up on that before it disabled or killed me but learned my lesson on that one. Single digit PPM might sound like low amounts, but you have to also consider what they are being placed in. If your setup isn’t configured to separate the chlorine gas into it’s own container, expect it to settle in the jar. have to remember heavier gasses will sink while lighter gasses will float, these reactions have a way of concentrating those gasses over time.

      3. “Gas chambers”* in Nazi concentration camps used hydrogen cyanide.

        *was more like a warehouse/barn with small holes in the roof, through which they dropped Cyklon-B cansiters, nothing like the gas chambers used for executions in the US back then…

  4. An interesting project but it’s a bit like entering a spark gap radio in an effort to understand how to link the 3rd world to the first.
    This technology has been used for quite a while (it was patented in 1906!) in industry & there are many feasibility studies on it for both potable water and industrial pre-treatment. If you want to bring electrocoagulation to the masses so the ‘citizen scientist can learn about coding, 3D printing, chemistry, teamwork and philanthropy” why not pick up the knowledge already out there and condense it?
    The wheel has been invented, instead of building your own n-gon to roll out, use the wheel that already exists to build a better cart.

      1. Because they’re rediscovering which minerals or how hot you need to get a straight razor, or which brand works best; how many turns of wire and whether or not a certain brand of earpiece has too much resistance to work. This has all been done before.
        My point is IMHO, they’re wasting their effort. Sure [Ryan] the info very well may be scattered around, or locked away in a $70 text book. But if you’re going to put together a kit on how to do this you can spend +3 months reinventing the wheel or buy a used text book on how they did it way back when. You can’t work hard enough to make it worth your time & presumably limited resources when there are countless open access journals & used text books floating around out there. Butler et al 2011 (doi:10.3390/w3020495) have a nice 2008-10 literature review on the subject. Some other open access articles I found on the subject.
        Getting hands on is admirable, but there’s no need to reinvent the wheel or only learn about other people’s mistakes after you’ve made them yourself.

        1. If only information were not locked behind expensive paywalls and instead was freely open and accessible so that humanity as a whole could save time and resources………

          1. Fortunately all the links I posted are open access. While a lot of research is indeed behind a paywall, this is changing. There are many open access journals, sites that offer pre-publish prints, and authors willing to email an authors proof.
            This stuff is widely used in industry, there’s loads of information out there. You may not get the cutting edge stuff without paying but it’s certainly enough to save you from reinventing the wheel.

  5. Why use electricity, when bacteria, yeast and other microorganisms will happily do it for free? The wastewater treatment plant we have in our town even heats their buildings by burning the methane that is produced. It seems like this process consumes power, when it could actually produce. No source code necessary. I apologize in advance for being ignorant, but it seems like a solution to a non-problem.

    1. Because of time and space limits.

      Used to have about 15-20 liters per week of stuff from my small business (was about 15 years ago) that did not want to dump in sewer, so had a drum out back where the stuff was dumped, then zapped. Sacrificial anode was Al bar, cathode was iron. Went from opaque to clear in 1 to 3 hours. Sludge hauled away and water dumped on lawn. Never heard the trees or grass complain.

    2. You still need to clarify the water at some point. Electrocoagulation can also help break down things like oil, nitrates, and a whole bunch more. In some circumstances it can be cheaper (if not necessarily more efficient) to do it this way.

    3. It really just all depends on the application and how fast you need that water produced. A big part of this project is just to realize what all can this simple process do with all the amount of variables out there yet to be tested out. There are amazing sand filters etc that do a great job at water purification with little economic resources required.

    1. I’ll be honest I don’t know enough about chemistry to answer this. Could you elaborate? Would this mean that efficiency is reduced as more aluminum chlorohydrate is created? Also would using two iron electrodes halt this issue and if so what other issues would that potentially bring up?

  6. It is a naive idea, you have no idea what the electrochemistry of the water may be, in a real-world environment, and you could very well be generating all sorts of problematic compounds.

  7. Typically there is no panacea for wastewater treatment. I built a large, continuous flow version of this some time back. It had consumable steel plates. Commercial systems use aluminum plates to increase efficiency. Stainless steel plates are less efficient than steel, and they corrode less which is actually less desirable. Counterintuitively, electrocoagulation is effective at removing metals. The electrolysis introduces oxygen and hydrogen that reduces some metals like hexavalent chromium to a much less toxic and less soluble trivalent form and oxidizes other metals. Iron from the electrodes is introduced as iron oxide which makes a nice insoluble flocculant. This flocculant coagulates other insolubles like metal oxides, etc. and settles to the bottom. One challenge can be that the gases generated at the electrodes floats some of the floc particles. Some systems use beaters to release the bubbles, but that can disperse the coagulated floc and make it harder to precipitate. Vacuum degassing might work. Also, scum on the plates can insulate and reduce the effective surface area. I’ve heard that some systems alternately cycle DC every few minutes to minimize scum and even out corrosion. Ultimately, I found that it is nice alternative to chemical treatment for the metals we were trying to remove, it wasn’t cost effective. It takes a lot of energy per gallon and chemicals are pretty cheap per gallon treated.

      1. Exactly, and some chemical treatment (oxidation and reduction). For example, hexavalent chromium is tremendously useful, but also hazardous. It is also very soluble in water. Chemicals like sodium metabisulfite can be added at the right pH and reduce the hexavalent chromium to a trivalent state, which is much less hazardous and less soluble. With electrocoagulation the hex chrome is attracted to the cathode and the hydrogen formation from the electrolysis of the water reduces the chromium without the sodium metabisulfite and the pH adjustment. We found that if we fed it 200 ppm Cr+6 bearing wastewater, that the clear product water had less than 1 ppm total chrome (hex and tri). That’s low enough and clear enough of suspended solids to feed to something like reverse osmosis. Again, it cost about 10 cents per 100 treated gallons. Chemical treatment is about 4 cents per 100 treated gallons. And the maintenance of cleaning and replacing plates has to be considered.

  8. This is dangerous. Dissolved metals can cause neural damage, aluminium can get into the brain, that’s why the metal is not used in food processing. Stop this and try using carbon electrodes.

  9. “…tens of thousands of gallons…”
    please move away gallons, inch, feet, arm, nose, penis and any other relic unit of measurements an move finally to standard system.

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