Sand Water Purifier

Discussion in 'Off Grid Living' started by Gopherman, Jul 21, 2014.


  1. Gopherman

    Gopherman Sometimes I Wish I Could Go Back to Sleep Site Supporter++

    My son made a small water filter using, From bottom to top, 2" layer of large gravel, 2" layer of Small pea gravel, 2" layer of activated Charcoal for aquarium filter, and the top is a 6 " layer of sand, all place inside a 1 gallon Iced Tea jar that has a flow valve in the bottom.
    After cleaning everything thoroughly we ran water through it until the water coming out was completely clear.
    He's afraid to drink the water now until he has it tested.
    Any advice?
    Does it have to sit for a while until the microbes build up in the sand? or Is it ready to go immediately?
    We are on well water so the water going in is already good to drink, but do pollutants in the sand or gravel pose a safety concern?
    I don't want to dampen his spirit because, I like that he did it on his own, but, I don't know either?
     
  2. BTPost

    BTPost Old Fart Snow Monkey Moderator

    Some issues with Sand Filters....
    1. They only work for a while, UNLESS, You have a Back Flush System, to Back Flush the contaminants out of them, every so often. The timing is determined by Flow Rate, and Size.
    2. They do NOTHING for Virus, or Protozoa, Protection....
    3. On your system, Outlined Above, the Activated Charcoal layer will need to be replaced, as the Charcoal is used up, by trapping Organic Hydrocarbons.
     
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  3. ghrit

    ghrit Ambulatory anachronism Administrator Founding Member

    Yes, test it, if for no other reason than the experience. Sand filters are effective, but are somewhat limited as BT notes.
     
  4. Gopherman

    Gopherman Sometimes I Wish I Could Go Back to Sleep Site Supporter++

    I told him next time to put the charcoal in a nylon stocking that way he can remove it. I have read the if you heat it to a very high temp it will clean and reactivate the charcoal.
    I also have heard that the top half of the sand has to be replaced every 3-6 months depending on usage. How do you know when to do this?
     
  5. BTPost

    BTPost Old Fart Snow Monkey Moderator

    If i were going to design a System, again, I would get an Opinion from @ColtCarbine Our Resident Plumbing and Potable water Monkey..... There are specific Calculations and Formulas, for making those Decisions, published by the EPA, and your State Water Department.

    My System has a 10 Micron Trash Filter before the Domestic Water Pump. Then a 1 or 2 Micron 10" Cartridge Filter, followed by a 10" Activated Charcoal Cartridge Filter, followed by a UV Light Tank, and then into the Cabin. I replace the Filters twice a year, and have Had NO ISSUES in 20+ years of drinking and eating with this Water. All our Water is collected off the Steel Roof of the Cabin, and they run thru this System, to make it Potable..... .....
     
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  6. Brokor

    Brokor Live Free or Cry Moderator Site Supporter+++ Founding Member

    It would be an excellent filtration project for use as a conditioner prior to water boiling. The filtering through sand and charcoal will improve the water quality, but as already mentioned, will not stop protozoa and bacteria. As a strictly low-end budget solution, I would also set up a camp pot, then boil the filtered water and store it in a larger vessel. This would make the water absolutely safe and all you used was your filtration setup and some firewood.
     
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  7. Gopherman

    Gopherman Sometimes I Wish I Could Go Back to Sleep Site Supporter++

    I appreciate the heads up. I also told him about the UV light tank. He is 22 and if you have children you know what that means. At this point of his life he is only willing to listen to his father, Just so much.
    I know the water he's putting in is already good, and free from bacteria. He's worried about chemicals and heavy metals.
    He watches the planes dumping stuff into the sky on a regular basis and its freaking him out, I too was skeptical about chem-trail's until I saw a UN Briefing where a Us Gov. Official admitted to it. So, having said that, he does have legitimate concerns.
    I have a line on a Medical Grade 12 v Sterilizing UV lighting system and a quartz crystal manufacturer that can make them customized to any dimension tube then it can be sealed with silicone and "Poof" its waterproof.
    Thanks again for the insight guys always a pleasure! ;)
     
  8. -06

    -06 Monkey+++

    We have a UV system and then use a Berkey for drinking/cooking water. Our wells have a lot of Calcium so kidney stones are a concern. The UV and Berkey take care of most problems. We have used Berkeys to filter creek water on a practice BO.
     
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  9. kellory

    kellory An unemployed Jester, is nobody's fool. Banned

  10. -06

    -06 Monkey+++

    Just met a lady who sells all sorts of filters. Her site is: filters fast.com and her name is Paige. Will be checking it for several types.
     
  11. kg4jxt

    kg4jxt Monkey

    Many cities use sand filters for a stage of water treatment so certainly if the water was safe before and all you have done is pass it through quartz sand and clean carbon then it should still be safe. The carbon can be regenerated by steam treatment, but you won't know if it was successful so you will probably just want to replace it periodically and save lab testing. Sand filters are often designed to be loaded at a flow rate of 2 gallons per minute per square foot of filter surface, and they are backwashed at 4 to 10 gallons per minute per square foot. Sometimes compressed air is used to help break up clumps that can form in the sand. If you are going to operate it for the long-term like that you will need a separate collection tank to catch all the sand that gets washed out by the backwashing and the backwashing will expand the sand bed a good bit so you will need about 50% headspace over the filter for that expansion volume.

    After filtering, the water in a municipal system is usually just chlorinated before it is pumped to the customers. The other common water treatment option is sedimentation; settling. A settling aid such as aluminum sulfate is added to the water in that treatment option, but it makes a sludge that is kind of a mess to dispose.

    Complications of filter systems arise with water that has a lot of iron or other mineral content. Sometimes it is necessary to aerate the water and prefilter through gravel or give some settling time to remove iron oxides; or it may be necessary to knock the pH down to neutral if there is a lot of lime content; otherwise the lime might cement the sand into a big mass of "cement"!
     
  12. ghrit

    ghrit Ambulatory anachronism Administrator Founding Member

    Yep, you are in my wheelhouse with that. Worth the emphasis is the storage requirements for backwash water that was previously filtered. As you note, sludge disposal can be a problem even if it isn't laden with odd chemicals (including all sorts of flocculation additives.)
     
    kg4jxt likes this.
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