New RO, Reverse osmosis

Discussion in 'Water Softener Forum, problems, installation and r' started by chevy427, Apr 15, 2012.

  1. chevy427

    chevy427 Banned

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    Air charged tanks require much more waste water. An air-charged tank when completely empty is very efficient wit a near 1:1 ratio of permeate water to waste water. But as the tank begins to fill, the air pressure against the product water increases and this pressure transfers back to the membrane. By the time the tank nears completion, the ratio may climb to 1:7. It also slows production considerably where the last 15% can take 7 times longer to produce than the first 15%. WOW tanks refill immediately after each use keeping the tanks full at all times. This factor alone makes it a very attractive benefit.

    The WOW design has virtually no back pressure and the membrane has no restriction. This is why it typically produces 35-45 gpd against typical ROs that produce 8-15 gpd.

    The "huge" possibility of water contamination is actually quite remote. Unless the tank is damaged due to freezing or some piercing instrument, I have never heard of the very thick liner corrupting. Agreed, Kinetico's K5 uses air-charged tanks when using its bacteria/virus filter to absolutely eliminate the chance. But, any other RO must never be used on a water that is micro-biologically unsafe.
  2. Well-man

    Well-man New Member

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    One possibility might be the APRO-5050-P for example.
  3. Well-man

    Well-man New Member

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    NEXT-RO vs. Standard RO with a Permeate Pump

    One example would be the Aquapurion APRO-5050-P.

    It uses the following:
    • 5 Micron Pre-Filter - PURITY PLUS
    • (2) Carbon Block Pre-Filters - OMNIPURE OMB934
    • In-Line GAC Post-Filter - OMNIPURE
    • 50 GPD Axeon (R.O. UltraTec) Residential Membrane - TF-1812-50
    Are the above componets well regarded?
    Last edited: Aug 19, 2012
  4. bcpumpguy

    bcpumpguy New Member

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    Waste water ratio as far as i know is not determined by air pressure, every ro i know runs at about 1:3 rejection rate meaning 1 part permeate to 3 parts concentrate. Yes Ro membranes can be run at all kinds of diffrent ratio, you can run no rejection whatsoever if you wanted to. In all RO's that we sell rejection ratio is is a figure of drain flow restriction combined with pressure. As the RO fills up the tank, pressure diffrence between the tank and incoming water begins to equalize slowly closing off the membrane valve that controls flow to the membrane. If the pressure in the tank drops the mebrane opens up flow again and the ro begins to make water.

    the wow design must have backpressure on the membrane, unless the water creating the mechanical pressure to push out permeate trough the fawcett magically disapears when the RO makes water. You say 35-45 gallons per day, the literature says it has a 50GPD membrane I wonder what temperature water with how much tds and what the Ph of your water is?

    the pile of ruptured pressure tanks at my shop would tend to argue with the remote posibilty of contamination.

    don't get me wrong I like the idea of the wow design, but I would never say it is better then an aircharged tank.
  5. ditttohead

    ditttohead Water systems designer, R&D

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    When discussing the pros and cons of certain pieces of equipment, is important to be careful as some people take any criticism of their design very personal. The NEXT Ro is a unique design, but it is more expensive, proprietary, and the advantages are so minimal that for the vast majority of people it makes no difference. The permeate pump gives you the vast majority of the advantages of the WOW design, is simple, well understood, trusted, and has been around for a very long time as well. WOW has been around for over 25 years, if it has not caught on by now, it is unlikely that it ever will. The advantages are more marketing hype than true advantages. Considering how cheap water is, and how cheap RO's are, is it really a major deal to save a hundred gallons of water a year? The average household uses 150-200 a day, so a savings of 1/600 is insignificant. Full line pressure until the tank is empty is neat, but in all reality, who cares? Who uses their ro tank until it is empty? Even then, at 6 pounds of air precharge, an ro will deliver the majority of it water at above 1/4 GPM.

    The WOW RO is an excellent idea, and an engineering masterpiece. Would I bother with one? No.
  6. LLigetfa

    LLigetfa DIYer, not in the trades

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    I think some fridge dispensers may have issues with low water pressure so I could see the NEXT RO being a benefit there.
  7. Well-man

    Well-man New Member

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    Dittohead,

    Thank you for your WOW analysis. What should I look for when selecting a residential RO system with a permeate pump? Are there well regarded brands & models of membranes, filters, or RO systems? Quality-oriented brands that are less likely to leak or less complicated to service correctly?

    Thanks
  8. ditttohead

    ditttohead Water systems designer, R&D

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    Location:
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    I would recommend staying away from smaller companies who have the best price. These generic RO systems can be made with some very low end junk and the companies offering these great prices usually fold up every year or so and start a new name so they can hide from the liability of their leaking and broken parts.

    Send me a PM, I can recommend a few good and reputable companies to you.
  9. Well-man

    Well-man New Member

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    Thank you.:)
  10. Well-man

    Well-man New Member

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    Location:
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    Has anyone had any experiece with the Watts Premier 531411 RO PURE RO-4 with optional Aquatec® ERP-1000 560041 Permeate Pump Kit?
    Filters:
    • 5 Micron Sediment Filter
    • 5 micron Carbon Block
    • 50 GPD Thin Film Composite Membrane
    • Carbon Post Filter
    "System tested and certified by WQA against NSF/ANSI Standard 58 for the reduction of the claims specified on the performance data sheet."
  11. ditttohead

    ditttohead Water systems designer, R&D

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    I am aware of that system. It is an excellent choice and will serve you well for many years. The only thing I dont like about it is the ERP-1000, I prefer the ERP-500 if it is going to be installed under a sink where it can be heard. The ERP-1000 is a great permeate pump, but it is "clicky" It makes a click noise that is noticable by many when it is installed under a sink in the kitchen. Most people dont notice it. Definetly a great choice.
  12. Well-man

    Well-man New Member

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    Dittohead,

    Thanks for the receommendation. When I Googled the ERP-500, I also found the following:

    Pentek RO-2500 4-Stage 50 GPD RO System w/ERP-500 Permeate Pump Kit
    • 50 Gallon Per Day GE Osmonics Desal TFM-50 Thin Film Composite Membrane
    • Pentek P5 5 micron polypropylene sediment filter
    • Pentek EPM-10 for Chlorine Removal,
    • Inline GAC Postfilter K2533-BB
  13. chevy427

    chevy427 Banned

    Messages:
    174
    Location:
    USA
    In my observations, When the tank is empty and beginning to fill, I get about three drops of concentrate for every drop of permeate. As the tank fills, it increases to about 5 drops and then before the system shuts down, I see a steady stream of concentrate water. I pull the line to the tank and the concentrate returns to about three drops, again. It is not a scientific examination but a pretty clear observation. My conclusion was that as pressure increases against the membrane there is a ratio change from permeate production and concentrate going to the drain.

    By completely stopping/plugging the drain flow? Naturally, that can't be recommended as it would defeat the purpose of an RO.

    So as the tank fills the flow rate of permeate production drops eventually shutting down completely, right?

    Not really magically at all. The patented valve releases it faster than incoming water. I think it creates a small negative pressure allowing incoming water not only to have no back pressure but 'invites' water to enter the membrane.

    I couldn't find anywhere in the literature where it states it has 50gpd membrane. If you have different information, please let me know. It does say it has a 50gpd capacity. I assumed that means a system capacity not that of the membrane. The rounding of numbers like that, though, I find are estimates (why not 48.6 or 53.2?) and should not be taken as definitive. Incoming pressure, temperature and TDS, among other factors, affect water production of any RO system. My estimates of 35-45gpd coming from installing one and judging by how long it takes to fill and shut off. Again, external factors can great allow for differences. Just my personal observations.

    I, too, have a "small" pile of failed bladders from air-charged tanks. I never denied the possibility of contamination. As of yet, I have heard of no WOW barriers failing in that regard. This doesn't exclude the possibilities but in my persoanl experience, I haven't seen one yet.

    I appreciate your experience and stated opinions. No problem. I have gone that route and now have switched for many reasons including what I feel as advantages of WOW tank approach to RO systems. I think the next best approach is atmospheric tank designs when space is available and demand is required. The WOW tank designs do have a few handicaps but not really a hinderance, yet.
  14. Well-man

    Well-man New Member

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    Location:
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    Watts Premier RO PURE RO-4: Amazon Customer Reviews

    Amazon Customer Reviews are mostly positive. However, there were several complaints about signifcant faucet leaks and that the tank was adding a plastic/rubber taste/smell to the water. One person even suggested replacing the Watts tank with an Amtrol to solve the taste issue. Pehaps buy an RO-4 w/o a Watts faucet & tank? Who makes a quality-oriented leak-free RO faucet?

    Are there any other recommend ROs?
  15. ditttohead

    ditttohead Water systems designer, R&D

    Messages:
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    Location:
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    Most RO manufacturers have multiple sources for components. I know whos tank they are using now, and they are great quality. Same for the faucets, all of the companies were sourcing from just a couple of faucet manufacturers, and there were some leak issuses, this has since been resolved. I would not worry about it. For the most part, reviews are going to be from the unhappy customers, not the satisified people, so take the reviews for what they are, unhappy people venting, and a few satisfied customers sharing their experience.

    FYI, they are one of my competitorsso I have no interest in promoting that product.
  16. Well-man

    Well-man New Member

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    Good to know - thanks!
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