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Reverse Osmosis 101

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  • Reverse Osmosis 101

    Would somebody mind posting a short introduction to RO systems - size requirements, cost of system, cost of consumerables, etc. This is for a 10 bbl brewhouse, 1500 bbl/yr capacity, very hard water.


    David Cohen
    The Dancing Camel Brewing Co. Ltd.

  • #2
    do you have space for a water tank?
    Larry Horwitz


    • #3
      I'm not sure I understand the question - how large of a water tank & why?
      David Cohen
      The Dancing Camel Brewing Co. Ltd.


      • #4
        David Im just starting out with a RO system.
        Basicaly calculate how much brew water you consume in an average brew day, calculate for more than one brew if you double or triple batch you should have a tank which will give you enough RO water to get through the whole day. they are often slow filling and fast to empty.
        You will use water salts, mine consumes about 1 kg per 1000 liters.

        the rest im learning, I just posted a question about mineralizing back the ro water. someone mentioned to mix back a % of city water which seems like a good Idea. so u may wish to add city water in valve on your RO tank.

        Every beer has its need of minerals, Im findig that RO water alone wont make a very tasty ale, its not so bad for lager styles. but I am at the point where Im learning more about water composition.

        Good luck, there are many here who will help you.


        • #5
          ro, ro, its off to brew we go...

          I used a RO system and here are some points to consider.
          -get a company that has experiance in industial, not just residential, instalations and get them to cost it out for you for free!!
          -you will need to soften prior to RO, so youll be buying softener salt.
          -all piping to brewhouse has to be schedual 80 PVC (or use stainless)- RO water will corrode metal. You will need a pump to get it there.
          -Put a auto fill valve on your new CLT so that the filter tops it off as you use. This way you dont run out of water.
          -bone up on your water chemistry, every beer will need salt additons. Every style can be made well. A scale weighing in gramms will help.
          -have a seperate source for cleaning but use it for rinsing outside of tanks, no water spots!
          Brewmaster, Minocqua Brewing Company

          "Your results may vary"


          • #6
            Here is a list of suppliers for you:

            I would talk to the Argad (Kinetico is a good brand) and Nirosoft.

            I would get a 15-20 barrel tank and run the RO water into it, and then feed it to your brewery equipment, CIP, and for anything that will touch the beer.

            You need something that can get you about 300 liters per hour which should be fine for your capacity. Although it doesnt hurt to go slightly higher. Control the unit with a timer, and a level switch on your tank. Then you won't have to baby sit it. If you do more than one brew per day, you will probably need a larger unit. I get by with that capacity on 20 Barrel brews.

            Take city water, and run it through a particle filter 5 micron, and then into a activated carbon filter. Use a water softener shell (the kind used in an average american house) complete with programmed backflush. Use at least 25Kg - 50Kg of Activated Carbon preferably from coconut shell carbon.

            Place another particle filter into the line right before your reverse osmosis. Use a 1 micron filter in it. Spiral wound cartridges are fine for this purpose. You want depth filtration. Now, these filters and carbon prevent particulates and chlorine from reaching your reverse osmosis membranes.

            Now the water is pumped into the RO Unit, the RO water will go to your holding tank, and the retentate (the high mineral content flush water) will have to go down a drain.

            Good luck and let us know what you come up with.

            PS: Adding City Water back into your RO water is a bad idea all the way around. Add minerals back to the mash. You can make whatever water you desire. Yes, minerals are very important to the brew, and you can't brew good tasting beer without them! The RO water is a blank slate that you can write whatever you want! It just depends on the style of beer you want to brew. That is where you can show your mastery of this craft.
            Last edited by zbrew2k; 08-24-2005, 12:51 PM.


            • #7
              All hail the gods of RO!

              Zbrew - you did everything but make the phone calls for me. Thanks for your help.

              David Cohen
              The Dancing Camel Brewing Co. Ltd.


              • #8
                You're welcome! I'd be happy to help consult for free...although I would need a round-trip First/Biz class ticket and accomodations.

                Again, let us know what you install.


                PS: Thank Google, all wise, and all it just me that thinks thats a bit scary? Type your own name in sometime....
                Last edited by zbrew2k; 08-24-2005, 12:56 PM.


                • #9
                  After all the discussion about RO from last summer, we're finally building our facility in Tel Aviv. Now that I have the water analysis in hand, I'm seeing that the only measure truly out of line with our planned menu of ales is the chlorides - measured at 234 ppm.

                  I would really hate to have to RO - big extra cash up front, inadequate water flow, wasted water, etc. I've seen one ref say with cl measure of 200-250 we should only brew stouts/porters; another says only beers > 1.050 OG. Anybody out there with cl > 200 not RO'ing?


                  David Cohen
                  The Dancing Camel Brewing Co. Ltd.


                  • #10
                    I know this is an old thread, but the information in it will be useful to people regardless of the post dates. With that in mind:

                    RO systems make purified water slowly. Production rates in the US are specified in gallons per day (gpd). Divide the GPD number by 1,440 to determine gallons per minute (gpm). The rate at which the systems produce water is significantly affected by the water pressure and water temperature. Increased pressure can generally make up for cold feed water. As a number of other factors can affect the speed at which RO systems produce water as well, it’s advisable to get a system that can produce at the flow you need, plus an additional margin. In other words, if you need 2000 gpd, consider systems at 2,500 gpd or more.

                    Also be aware that the gpd ratings mean just that – gallons per 24-hour day. If you need the full system capacity to be produced during an 8-hour workday, a higher capacity system is called for.

                    RO systems of nearly any capacity – from just a few, to millions of gallons per day are available. “Residential” systems are typically line pressure (used without a pump, or with low pressure pumps) systems up to about 150 gpd. “Commercial” RO systems produce water faster, utilize high pressure pumps, and of course, are more costly.

                    When we size water treatment systems for breweries/distilleries, we balance the water demand against the RO water production rate, and the available tank storage capacity. If you have a large enough tank, you may be able to use a lower capacity RO system. For instance, if the RO unit works through the night to fill a storage tank, you can gravity flow or pump from that tank at whatever flow you need – nearly independent of how fast the RO filled the tank.

                    A tether float switch is a good way to control the water level in the tank. Although a simple horizontal float switch, or even a float valve would work, they would cause the RO to kick on in response to even a slight decrease in water level. After a short run time, the RO would kick off. We call this “short-cycling.” For a number of reasons, it’s better practice to have the RO system kick on less often, and stay on for an extended period of time. A tether float switch is an inexpensive, maintenance-free, reliable solution.
                    Common prefilters (“prefilter” is anything that treats the feedwater before it reaches the membrane) for a residential-scale RO system are a simple sediment filter and a carbon block (avoid GAC filters here). For commercial systems with higher flows and where replacement membranes are more costly, prefiltration often includes particulate removal (sediment filter(s)), backwashing carbon tank(s), water softening, and treatment to remove other undesirable or damaging contaminants (e.g., iron, manganese).

                    A post above mentioned using “at least 25Kg - 50Kg of GAC preferably from coconut shell carbon.” A bit of a different take here: size your carbon filtration based upon desired flow in gpm. If you can specify your desired flow from your RO system, your vendor can appropriately consider both the permeate and concentrate flow, and size the carbon tank, automatic backwashing valve, and the amount of media (GAC).

                    Being familiar with some jargon will help you communicate with your vendor.
                    Permeate, or filtrate: the purified water produced by an RO membrane
                    Concentrate, or retentate: the water sent to drain from an RO membrane

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                    Buckeye Hydro
                    Water Treatment Systems & Supplies


                    • #11
                      When considering a reverse osmosis system, it is important to note that RO production is rated @ feed water temp of 77F. Colder feed water will drastically diminish your RO water production. Assuming your RO is rated at 100 GPH:
                      Feed water @ 77F= 100 GPH
                      Feed water @ 70F= 87 GPH
                      Feed water @ 60F= 72 GPH
                      Feed water @ 50F= 58 GPH
                      As you can see, if your brewery is located in a Northern climate your RO production may be seasonally reduced by 40% or more. Be sure to consider this when sizing an RO system. Preheating the feed water is always an option as well.

                      Jon Cox
                      Pure Water Tech of WNY