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Forum Index : Electronics : Electrocoagulation
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norcold Guru  Joined: 06/02/2011 Location: AustraliaPosts: 670 |
In another thread have spoken about dams and solar pumps. I have a problem with "cloudy" water in my main dam, the "cloudy" caused by clay. It does not settle out between wets, and then the new wet introduces more. There is a chemical solution, adding Alum (hydrated aluminium sulphate)to the dam water, which basically means you change the Ph of the water from alkaline to acidic. There is a method called electrocoagulation that is gaining popularity. Basically my understanding of this is it is a little like the air ionisers, but applied to water. Am looking for such a device I can construct and mount near the suction of my pumps utilising a small amount of the DC solar power I use to power the pumps. Perhaps a 4M member has some experience here and can assist, as far as electronics go I am a "paint by numbers" kit constructor, thus can probably build such a unit but not understand the theory behind it. As my pumps only pump to 10 l/min, am thinking of a sort of inverted funnel on the suction with the devices "electrodes" near the apex of the funnel. I am trying to avoid mechanical filtering, this only introduces more maintenance, and the particles are minuscule. We come from the land downunder. Vic |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
You are partly correct, except the lime causes a Ph shift to alkaline. (not Acidic) The method is called Flocculation, where a PH shift from Acidic to Alkaline causes the suspended particles to flock together, and become heavier than the fluid they are suspended in. Its a common system used in almost every town water supply for filtration and many industries, for example to oil field use Flocculation to recycle drilling fluids from suspended solids on surface hole drilling. Its a primary filtration system that's used as common as the mud that clouds the water. In most cases it only requires a small change in Ph to Flocculate a dam, it can be calculated for the quantity of Ph adjuster to water mass required, with little or no detection to taste. One of my prefered additives for a Ph shift with Flocculation was cement powder, it works as well or if not better than lime. Try a test, fill 2 jars with cloudy water, keep one as a base sample, to the other add a sprinkle of lime or cement powder, shake both jars and leave them to sit, within an hour or so you should notice a difference in water quality between jars. There is also an added advantage to using Flocculation with a dam, it adds a filter cake to the floor of the dam, which helps reduceses losses of water through the soil, all those fine suspended particles settle out and cake to the bottom making an even tighter water proof layer. Pete. Sometimes it just works |
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| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Pete, Have to disagree with you here, Alum(Aluminium Sulphate) not lime (Sodium Carbonate) turns the water acidic(Please reread my original). My water is alkaline as I suspect is most clays. I`m talking Electrocoagulation not Flocculation, but you are correct Flocculation has been around for eons. Adding lime or cement to my water whilst it may settle the clay will further compound the problem I have with scale, which is Calcium Carbonate buildup on pipes etc. Adding Alum to my water will cause corrosion unless I get the process spot on which is way beyond an individuals resources but not a Water Boards. I do not drink this water it is only for irrigation purposes, just trying get away from having to continually unblock sprays. My understanding of the process of flocculation is both alum and soda ash can be added to the water(to achieve a satisfactory Ph), separately of course or you get an immediate chemical reaction. I wish to try the new "kid on the block" electrocoagulation, I have the DC power present. Just am not financial enough to afford to purchase a commercial electrocoagulation unit. Believe there is a KISS method that can be applied here. We come from the land downunder. Vic |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I wonder if you could use some sort of cyclonic separation - http://en.wikipedia.org/wiki/Cyclonic_separation Works for vacuum cleaners, but not sure on muddy water. The fact the mud stays in suspension with the water probably means it was the same weight, so may not separate with a cyclonic process. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
You have a 2 part problem by the sounds of it, with sediment and mineral salts, and im doubtful one method will solve both. Do a google search on "Electronic water softener" you should get lots of basic circuits. From what i remember most are not much more than a 555 timer running at 15Khz and a single ended wire coil wrapped around a plastic or copper pipe (not steel) Pete. Edit. I just had a look at what some claim to be "Electrocoagulation" and they are nothing more than a hydrogen generator cell (browns gas)that would use mass amounts of power. Wiki seems to suggest the radio wave method as per above with the Electronic water softener, which would require only a small amount of power. Sometimes it just works |
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| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Electrocoagulation (EC from now on) goes back over 100 years but is gaining popularity now apparently for 2 reasons. The cost of chemicals in the flocculation process and the chemicals are not environmentally friendly. But there is, as always heaps of bogie claims out there with dodgy operators out for a quick quid. Cyclonic separation should assist, as clay I imagine is heavier then water and would not be difficult to implement in the "inverted funnel" such as used in precleaners on engines for dust removal(dozers,4WD etc). Just a matter of designing and building this funnel to do so, plus it seems some method of agitating the water is required in the EC process. The commercial EC process uses steel as both the cathode and anode. As I wish to use only a small current say 100 ma to 500 ma, with an apparatus to adjust this current( to fine tune), remembering that my voltage would fluctuate(6v to 24v) with the suns intensity and pumps draw, how would I go about this simply? Remember I "paint by numbers" , theory is OK but a rough circuit diagram with values of components for a test would be on the money for this lad and much appreciated. I am not interested in clearing the complete dam water just the bit the pump pumps. About my water, had it tested way back. Carbonates, heavy metals etc were all well within the safe limits for humans, except the lab had a footnote that the fluoride level was approaching the upper limit, apparently that is unusual although not when you look at our local geology, there is fluorspar amongst a lot of other minerals in the hills that feed my dam. We come from the land downunder. Vic |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
I very much doubt that Cyclonic separation will assist at all, as back in my oilfield days we had some pretty large Cyclonic scrubbers to remove sand and silt from drilling fluids, and often the drilling fluids were made up from a clay, which the scrubbers had no effect on. As for a paint by numbers, What colour paint are we talking about? as there is dozens of different methods out there all with different paint colours. Your suggestion of 2 steel probes is not correct from my understanding and you would require 1 x steel probe and 1 x aluminum probe, as its the exchange of ions between the metal that puts Alum into the water which causes the flocculation. Try a test fill 2 jars with dam water, keep one jar as a control, the second jar place a steel electrode and a aluminum electrode in the jar, connect the steel electrode to a positive terminal of a 12v battery and the aluminum electrode to the battery negative, current will flow between the probes and alum will be added to the water, see how long it takes for each jar to settle. Depending on the dissolved salts in the water will depend on the amount of current drawn, my guess is a few milliamps up to perhaps 200 mA. The size of the electrodes and the distance apart will also effect the current required. A test i done here with a jar of muddy water and probes made from flat bar 25mm x 3mm and 150mm long took about 5 minutes to floc the water and drew 50-100 mA at 12 volts. (probes were spaced about 4mm apart with a bit of plastic that was handy) The voltage is not important so no regulation required 6-24 volts is ok. Once the alum is in solution you can stir the fluid up and it will clag back together almost instant. Then all you require is some form of a settling tank to allow the solids to precipitate into, perhaps Cyclonic separation might work here. Pete. Sometimes it just works |
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| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Pete, Many thanks for that, Google Kaselco Texas, have a read. They use mainly steel cathodes and anodes, process does not require a chemical to be produced from the electrodes by my understanding. Ok you make it sound easy, will go with trial just spacing electrodes to control current and see just where it goes. Not concerned about dissolved salts just the clay. The colour or number of paint used is of no importance, its the results that count. I`m a real whore.  We come from the land downunder. Vic |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
That is because it is easy, other than making it all work efficient enough, and a way to deal with the solids. There is many factors at play and each depend on what method/materials you use, as just hydrogen production (or HHO )that occurs when you pass a DC current through water, will affect the SG of the fluid or weight of fluid by volume, which then affects the suspension of particles within the fluid. Although the hydrogen produced at 100mA is next to nothing, so thats not the full solution. Different mineral ions have different charged molecules that make up the element structure, so for some metals you get better results than others, also some minor metal elements will be lost into the fluid, its also a matter of which metal gives the best result with a by product of what element, without causing a high toxic level of elements in the water. Almost everything can handle Iron as a element in reasonable amounts, but copper for example becomes toxic to many plants above 0.06%. (no copper probes) Perhaps that is why iron is used, although many commercial systems use Aluminum and Iron because it works better, and Alum is the most used flocculation element for cost and result. (FMU) At the end of the day you are just trying to change the +/- charge of some particles to attach to others, so they flock together and become heavier combined particles. Pete. Sometimes it just works |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
If you are a whore, then you best put in, or this pimp will leave the thread. Here is a test i done earlier. it was not conducted under test conditions, other than what appears to work best. You have to guess which glass was the control sample. The one on the right was done first, with V+ to iron and Gnd to aluminum, and has had more settling time, the one on the left was V+ to aluminum and Gnd to iron, it has have less time to settle, although as it did it lost the yellow tinge the right glass has. 
Pete. Sometimes it just works |
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| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Once again many thanks for that Pete, now its just a matter of putting it to practise. Will be onto it and post back once I`ve given it time to prove or not. We come from the land downunder. Vic |
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Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1345 |
and the 3rd guess is which one is Adelaide tap water and no prizes for picking the middle one.......... |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Bryan, Well Adelaide do claim a meal in every glass, so your not far wrong. Using Adelaide tap water in my kettle it goes brown/black on the inside with in 2-3 months, using rain water it has a small faint colour after several years. Some years back i drove for semi's carting cement and lime, every second day i or others would unload 30 ton of lime to water treatment plants across Adelaide, that's about 15 ton a day being added to our water. Whilst unloading i would walk through the chemical storage shed, and it was pallet after pallet after pallet in rows of chemical that was added to our water, all to just make it healthy for us to use. ........... (what ever happened to "just water") Pete. Sometimes it just works |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1345 |
Yea well living up in the hills for 10 years on rainwater does clear the mind and I do remember when Jessie our oldest daughter first tasted Adelaide tap water. She spat it out and asked mum I wanted a drink of water what is this........ These days even with a coffee at work I can taste if it is made with Adelaide water and if so I take my own ground coffee beans, some Harvey long life milk, a 5 litre jug of rainwater and my $20 expresso machine to work for making a nice pure tasting caffine..... Now to keep on topic of throwing voltage into water next time a politician comes around and if one has a pool throw him and a live toaster in the pool and see if water stays clear..... |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Ehrr.... thats called "Electrocution" and not "Electrocoagulation" there is a slight difference in the end result of water quality, one is drinkable after the process, the other is made toxic with the solids addition during the process. Pete. Sometimes it just works |
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| BobD Guru Joined: 07/12/2011 Location: AustraliaPosts: 935 |
I just came back from a week at West Beach and I thought the water wasn't too bad now compared with how it used to be way back in the 1970s. Mind you, I drink water from the Murray from up near Albury and although the water is clean, sometimes there is so much Chlorine it seems like you're in an indoor pool. I guess it all depends on how many bugs they find in the water. Way back then I used to stir my Adelaide acquaintances by telling them it was the only place in OZ where the look before and after a flush was the same. On one trip I stopped overnight at Narrandera and I realised that I was wrong. |
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| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
You folks are making me feel a little guilty about a wee bit of clay in my water. Bloody hell even got naturally occurring fluoride. Being a country lad brought up on rain water, I understand where you are coming from every time I`m forced to go to the big smoke. Lucky there is XXXX. Be awhile before I go down the EC path as am currently down at fishing hut on the Hinchinbrook channel, whilst fishing (wishing) come up with many world saving ideas. Although EC may be the way to go, time will tell. Send you all a barra scale. Two for Pete. We come from the land downunder. Vic |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1345 |
AH there's a big problem, it is said said Qlder's are 'mad as a cut snake' and what the bet the above liquid which pass's off as beer is the culprit. Vic for FFS grab a slab or 3 of Coopers Pale Ale to give your body a good cleanout and be aware don't even use XXXX to top up your car's radiator......... |
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| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
XXXX and Bundy Rum, the nectar of the Gods. In truth I`ll drink anything but City water, even VB. Qlders are born to keep the rest of OZ sane and whoop the Mexicans at footie, even against the odd 7th play try etc 
But your right Coopers Pale Ale is a good drop, almost up there with XXXX. You mean cartons not slabs, slabs are where stiffs are stored. We come from the land downunder. Vic |
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| isochronic Guru Joined: 21/01/2012 Location: AustraliaPosts: 689 |
Ions with multiple charges (aluminium, sulphate, iron, calcium etc) will crash the suspension out, much more than ph, but then the ph changes are usually caused by other things. eg more acid waters and mineral water often have iron and calcium traces. I wouldn't drink anything with alum (aluminium ammonium sulphate) in it if I could avoid it. (So said from a flat dweller that can see blue copper marking from a tap drip...they add it to control algae apparently, ecch.) If you have some gardening stuff eg potash or ammonium sulphate etc a small amount would work. Other wise you will have to dissolve metal electrodes somehow.. If you ask me the whole country is now completely flocculated anyway, you could write to the minister for science I guess... uh, never mind.. 
edit : at the risk of algal growth, a whiff of super (superphosphate) or similar should add calcium and clear the water a treat. But (as mentioned) dissolved salts often cause blocks. |
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