RO Systems

[slick]

Looking at getting an RO system and was wondering what people are using. Thanks, Carl

[mabrungard]

I would strongly advise against a proprietary RO system such as GE or Whirlpool or Kinetico. You would be tied to overpriced equipment and replacement parts.

A good thing to look for is a reputable membrane manufacturer. Filmtec is one of the best and worth a consideration. There are plenty of suppliers that assemble RO systems. When you think about it, all the filter canisters and components are pretty much the same and all are going to be relatively sturdy. The differentiators are the membranes and cartridges that the supplier provides with the system. Most of the components come from the same suppliers.

You have to have a activated carbon pre-filter to remove chlorine from the incoming water supply. Most RO membranes cannot tolerate chlorine. You also need at least one particulate filter to keep grit off the membrane.

You will find that the typical RO systems are listed as either 4 or 5 stage units. That means that they have either 4 or 5 filter units in the treatment train. For instance, a 5 stage unit will have 2 particulate filters, a activated carbon pre-filter, the RO membrane (filter), and a post-treatment activated carbon polishing filter.

All RO units produce water at a slow rate, 50 to 150 gallons per day. On the low end, that means its trickling water out at 4 oz/min. Therefore, having a storage tank that is sized to meet your typical brew day needs and other household needs is a requirement. Bigger is always better when sizing a tank.

A RO unit should have an auto-shutoff valve so that it doesn't run all the time. If you will be storing RO water in an open tank, then you should have some sort of float valve in the tank to shut off the RO system. If you're storing RO water in a pressure tank, then you should consider including a Permeate Pump in the RO system. The permeate pump isolates the downstream side of the membrane from the storage tank pressure. Since the differential pressure across the membrane defines the overall efficiency of the membrane, keeping the downstream side of the membrane at a lower pressure is a good thing. This adds about 10 to 15 percent to the efficiency of the RO system when you are storing water in a pressure tank. The bad thing about a permeate pump is that they are noisy. When the RO unit is running, the permeate pump sounds like a slow beating heart. If your system is going to be away from your living area, then the noise should be tolerable. If you will have your system in your living area, then maybe you should just accept that you'll have poor RO recovery efficiency and don't have a permeate pump.

Since water viscosity affects the RO recovery rate and efficiency, you should plan on keeping your system in a warm area. Expect poor performance if the system is exposed to cold weather.

I picked up a nice system from a Canadian company for my new house a few months ago. I found it on Ebay. Do a little investigation on a RO system supplier's website and make sure they have high quality components and cartidges. Don't be afraid of no-name brands since there is little difference after the name plate comes off.

Martin

[ajdelange]

I had a couple of GE units (from Home Depot) which I think I paid a little over $100 (each) for and made a lot of beer with them. The problem with them is that they only produce 5-10 gal per day so it took the better part of a week to collect the 75 gal I use in a typical brew day and if I ran out on brew day I was out. I eventually replaced them with a Titan 500 which gives me a liter per minute and is plumbed into the brewery and lab. Designing and installing the system around this (atmospheric tank, pressure tank, controls, safety devices) was a lot of fun for a tinkerer like me but I don't think most would want to invest the time, money or space involved. But it holds 100 gal in the atmospheric tank, 60 gal in the pressure tank and in the time between dough in and the commencement of boiling (on a triple decoction brew day) can produce another 90 gal so I can't run out.

[ajdelange]

Martin's post went in while I was typing mine so I read his after I put mine in. His post leads to a couple of further comments.

I'll defend the GE units on price. They were pretty cheap and I never had to replace the membranes. As they were never used for anything but brewing water it just wasn't that much of a load on them. I'll note that chlorine/chloramine was not at issue for me as I'm on well water and that does contriubte to membrane life. OTOH I have reasonably hard water and quite a bit of silicate (28 mg/L). It's note worthy that neither of these jammed up the membranes but at the low recovery rates at which these units operate they are quite tolerant of hardness (the limit is in the manual). The Titan can be operated at much higher recovery rate and if you have hardness, silicate or indeed any other ions you have to think about what the "limiting salt" is and adjust recovery rate to prevent the limiting salt from precipitating at the membrane face. One way to insure that calcium carbonate isn't the limiting salt is to soften the water before it reaches the RO unit. As sodium carbonate is much more soluble than calcium carbonate something else becomes the limiting salt. In my case I expect it's going to be the silicate and we'll see what kind of life I get out of the membranes. These considerations are beyond the understanding of the average homebrewer and so you are almost dependent on the supplier or installer of the system to advise you. I will say that the guy I bought the RO system from did ask me for a feed water analysis and mumbled something about the silicate but didn't hesitate to sell me the system.

The Titan system, by contrast with the GE's, was quite expensive and but the tip of the iceberg. After the two tanks, the pressure relief valve, the float switches, the pressure pump, the pressure switch and backup, the controls/timer box for the pressure pump, floats and pressure switch and the plumbing I probably wound up spending twice again what I spent for the RO unit itself. And if I'd had a contractor integrate that stuff instead of doing it myself it would doubtless have been lots more. Then as I mentoned above the softener is required (or at least a good idea if the feed water is hard). I did want to add the comment that if a pressure tank is involved it is imperative that there be circuitry which turns off the pressure pump when tank pressure reaches working pressure and backup to prevent the tank from bursting if that circuit fails. In adition to that there must be a blowoff valve in case the backup fails.

The pressure pump I used is the demand diaphragm type used in cabins, on boats etc. It makes a sort of "brrrrrr" noise - not too loud but not what you'd want in the living room. The permeate pump on the RO unit itself is a gear motor which is really reasonably quiet but all the stuff is in the garage and with the door between the house and garage closed you can't hear it in the house.

[slick]

Thanks for the information. What about a portable unit such as this. http://cgi.ebay.com/Portable-Mini-Rever ... 4155287d6b. I am doing 5 and 10 gallon batches about 3 times a month. Thanks

[Mylo]

so it took the better part of a week to collect the 75 gal I use in a typical brew day...

Dat's a MAUUN!


Mylo

[beltbuckle]

I've got the Typhoon system from airwaterice.com. I love it.

http://www.airwaterice.com/product/1TYPHOONIII/TYPHOON-III-AQUARIUM-RODI-75-or-100-GPD.html

My municipal water is 350-400 ppm of total dissolved solids. I measure the RO/DI water every once in a while to make sure it is still effective. I'm still at 0-1 ppm TDS.

here she is mounted on the wall


Takes about 3 hours 45 minutes to completely fill my 15.5 gallon (sanke keg) hot liquour tun.

[ajdelange]

Apparently many people successfully use aquarium RO systems. Your rejection (350 --> 1) is a little suspicous though. That's 99.7%.