Costco Zero Waste RO unit?

Discussion in 'Equipment' started by Vincerama2, Jun 1, 2011.

  1. Vincerama2

    Vincerama2 Evil Overlord

    So Costco has a "Zero Waste" RO Unit. I think the way it works is this. It's just a regular RO unit, but it takes the regular "waste" line water and PUMPS IT into the hotwater line. So the source is the cold water tap, and the waste, instead of being dumped down the drain, gets injected into your hotwater line/heater where you then take a shower with it.

    Seems sort of like a good idea, except that you have to run a pump and which is more wasteful, the water or the pump? Assuming that the "waste" water is actually water that has run through your 5 pre-filter cartridges anyway, it won't really require more processing at the sewage plant, much like if you just ran the water while brushing your teeth.

    I think Spectrapure has a zero-waste RO unit as well, but it recirculates the "waste" back trhough the RO membrane? Don't quote me on that, I'm not sure.

    Anyway, an interesting idea. But I think it's better to capture the filtered "waste" water for your garden somehow.

    Anyway, food for thought. Costo filter - smart or dumb?

  2. rygh

    rygh Supporting Member

    Hmm, very interesting.

    A side bonus - zero waste = no need for a sink.
    Ok, probably rarely an issue for most people.
    But for me, in the garage, I have a hot water heater, but no sink, so it would enable me to put it inside.

    Note that if you plumb it wrong, and do not send it through the hot water heater properly, there
    is a slight health risk of legionnaires disease. Bacteria will grow in the RO unit. You need the high
    temps to kill it.
  3. GreshamH

    GreshamH Guest

    OK so your hot water is not in use and you RO is in use. Your current muni pressure is off the charts like some areas and you actually have to dial it down to get the pressure right for your RO.

    Please explain how this will inject water into something with greater pressure in it?
  4. newhobby

    newhobby Guest

    I think he said there is an electrical pump that will have to generate greater pressure to infect the waste into the hot line. That's what I understood.
    So, his question was really: Is it better to waste water down the drain or waste electrical energy to inject waste water into the hot line?
  5. GreshamH

    GreshamH Guest

    You have 5 stages prior to your RODI? Most have 2 or 3 prior and 1 or 2 post (which is the DI portion). More water is a larger burden on the water treatment plant. The second you put it into the waste stream of the muni, it has to be treated just like all the other water. Just like your aquarium or any filter, there is a max amount of water they can handle which is one of the causes for sewage dumps when we get large storms.

    he said and I quote
    . There are booth electrical and non electrical powered booster pumps (that is all the unit uses).

    Regardless... which is more costly... electricity or water?

    I suggest reading the reviews.
  6. sfsuphysics

    sfsuphysics Supporting Member

    Yeah never understood how these work, water can't compress, so if you put water into a system that's full it needs to go somewhere, since it's "zero waste" I'm guessing that translates into your hot water heater really isn't full so you pump more water into that. Now that might work for drinking water quantities of RO water, but what happens when you fill up a 30g brute?
  7. Gomer

    Gomer Honorary Member

    For me, the solution is rain barrels. Plants are happy later :-D
  8. rygh

    rygh Supporting Member

    It circulates.
    cold water => RODI => waste => pump => hot water heater => water pushed back up line in your house to cold water
    Which could in fact go again through your RODI, endlessly.

    As long as the amount of water in your pipes/water heater is large compared to your RODI,
    seems like a very workable system.
    But I have no idea on environmental/cost tradeoffs. If you have a solar powered pump - maybe that would
    be totally "green".
  9. sfsuphysics

    sfsuphysics Supporting Member

    Ok I got you all the way to water heater... when you say it's pushed back up line you mean towards the street? I could see that, wasn't aware those meters could run backwards, however I think the city would have serious issues with you pushing water back into their system.

    Now if you mean push it back to the cold water line... ehh.. not sure that'd be terribly favorable, since you're recleaning diluted brine, and probably have to replace your membrane much more often.

    But then again, I go along the lines of Tony, my water goes to my backyard, I have a 300g rubber made back there, with fish in it for mosquito issues, and water goes there to various parts of my yard when it overflows, or I have a valve that I open if I want to flood a particular area.
  10. rygh

    rygh Supporting Member

    Not back to the street, no.
    Keep in mind, you are taking more water from cold (waste + cleaned) than you are pushing back into
    the hot (waste only). So overall, you are still bringing water into your house.
    But the flow would go backwards through your hot water heater, out the intake, to where that
    meets the cold water line.
    Yes, you are re-cleaning the waste. Not the best.
  11. Mr. Ugly

    Mr. Ugly Past President

    Brilliantly funny :D

    And I was about to comment about backflow prevention...
  12. iani

    iani Guest

    What Norman said. I would think doing this would be against some plumbing codes.
  13. tuberider

    tuberider Guest

    "hot water heater" lol
  14. Vincerama2

    Vincerama2 Evil Overlord

    Honestly, I wouldn't buy one because less moving parts is better, IMHO. Currently my waste water just goes down the drain. I feel guilty when I hear the RO unit running. But on the other hand, I give my kids a bath everyday and they waste a lot more water depending on how stubborn they are about getting out of the shower. In fact once you have kids, everything that you try to do to save money, water or electricity just becomes a blip on the giant bucket of resource consumption compared to those earth destroying kids!

    I'm thinking of someway to get my "waste" water plumbed into my Earthbox garden, other than just filling up a big tub and watering by hand.

  15. GreshamH

    GreshamH Guest

    I've seen some very creative rain water collecting systems for watering gardens. Those can easily be applied to what you want :)
  16. Vincerama2

    Vincerama2 Evil Overlord

    Yeah, I think for now "giant 1/4" tubing going into the backyard to a container instead of the drain" will work. The Earthbox watering system is a bit more elaborate but I think I can get it to gravity feed. Otherwise I think one of those rainbarrels with a faucet will work nicely too!

  17. Gomer

    Gomer Honorary Member

    And for the SAF crowds, something like this
  18. zepplock

    zepplock Guest

    That's an interesting thing. Can I hook my RO to it? I'll need to drill the side of the house though ;-(
  19. Vincerama2

    Vincerama2 Evil Overlord

    Well Vlad, that's the advantage of owning! You can put holes all over the place if you want to! ;)

    I'm thinking that RO "waste" water into a large container would also make a nice earthquake reservoir, assuming it doesn't fall over or is crushed by your collapsing house!

    That 85 gallon pot that Gomer linked to would be ginormous!

  20. Gomer

    Gomer Honorary Member

    85g with a 4:1 RO unit is the waste from making 21g of RO water.

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