Guide to Reverse Osmosis Systems for Homebrewers

At some point in your brewing career you are going to become interested in taking your water chemistry to the next level.  As part of that, you might come to the realization that you want to improve the quality of your water and stop using the water from a garden hose or you might want to cut down on the inconvenience of having to go to the store to get your water.  I had waited a long time to do it, but I’ve had my system installed for 2 years now and I don’t regret the expense one bit.

I put together a guide on reverse osmosis systems detailing

  • The basic components of a RO (Reverse Osmosis) system
  • Some of the considerations when choosing a system
  • A brief explanation of how they work
  • How I chose to install my system

Here is a link to the full guide:

http://fermware.com/reverse-osmosis-system-installation/

This is awesome.  Thank you!

Thanks!  I hope it helps.

The one thing that keeps me from a RO system is the amount of “waste” water that goes down the drain. Doesn’t it take 3 - 4 gallons of water just to make 1 gallon of RO? I’m having a hard time getting around that and have just been buying distilled water at .89 per gallon knowing I’ll use every last drop. Plus - doesn’t it take hours to even collect enough water to brew with? I tend to shy away from anything that increases my prep time for brew day.

I could be looking at this all wrong. Also - my “facts” that I listed above could be myths? If so - straighten me out!

The number I referenced is 2.5 gallons for every gallon produced.  I did not measure to verify that value.  What I’ve learned since posting is that different system pressures can alter the amount of waste water.

If you search the internet, there are lots of good ideas on how to re-use the wastewater.  Mostly the use looks to be for watering your garden and also supplementing it with tap water to reduce the concentration of what the RO system has just removed.

There are different levels of waste in everything we do, you just need to decide what’s best.  Driving to get the water, the disposable or recycled containers, the wastewater from the system at your house, the wastewater at the plant that made the store water.  It could go on.

Yeah, that’s definitely a good way to look at it. Great perspective!

Hi guys - Russ Romme with Buckeye Hydro here.

I wanted to comments on a sentence in your write up:  “Number of filter stages (more is better??).  I chose a 5 stage system.  The more stages, presumably a greater filtration level.”

We find this concept is a common area of misunderstanding, especially with first-time buyers of RO’s.

Consider a three stage system consisting of a sediment filter, carbon block, and RO membrane the default configuration.  Add filters to this configuration only if warranted.

If you want to add a pressurized storage tank to the system, then you’ll also need an inline taste and odor filter. 
If you have chloramines in your water, it makes sense to add a special chloramine-type carbon block before the membrane.

There is a price you pay every time you add a filter.  First, you’ll have to pay for the filter, and then you’ll have to pay to replace it periodically.  Next, if the added filter is before the RO membrane, you’ll lose a bit of pressure pushing the water through the filter.

Take home message:  Understand what each filter does, and don’t assume that “more filters=better filtration.”

Russ

One more comment about the system depicted in the write-up.  It has a GAC filter as one of the prefilters.

Prefilter=any filter that touches the water prior to the water reaching the RO membrane.

GAC is an older style product that for purposes of prefiltration, has been replaced by carbon blocks.  Carbon blocks  offer much better performance and essentially the same cost.  Blocks are also much cleaner than GAC.  So in general, avoid use of GAC as a prefilter in RO systems.

Russ

so for those that are thinking environmentally… there are ‘zero waste’ systems out there. Know that the ‘waste’ water is pushed back into the ‘hot’ side line. You also can NOT use one of these systems with a tankless water heater.

I’m not sure if you were referencing the system I was posting about, but it does not go back into the water supply, it simply exits to the drain at the sink, so a water heater configuration should have nothing to do with the RO system.

If the source water for your RO system comes from a well as mine does, you have to soften it first before running it through the RO system so you don’t prematurely destroy the membrane (my well has 400 grains of hardness which is a lot).  Softened water has sodium in it from the cation exchange process of substituting softer sodium ions for the harder calcium ions.  I am a bit leery of introducing sodium laden RO waste water into my garden as it could upset the mineral balance in the soil and effect plant growth, IMHO.  I just use the hard well water if I need to water the garden or just let the rain do it.

Indeed I have a well and I am a bit anxious about running the waste water into my septic tank, but I checked with the septic guy and he assured me that he had never seen RO waste water adversely affect a septic tank and effluent lines arrangement, but he cautioned that he only has 40 years experience!

not referencing your post. the system you reference spits the wastewater down the drain. I called out the ‘zero waste’ systems that exist and how they push the ‘waste water’ back into the hot side line which would end up in a traditional water heater. If you have an on-demand water heater you can’t use a zero waste system as there is no tank for the waste water to end up in.

The  R.O. waste water won’t effect the septic tank since the waste water is already softened (your guy with his miniscule 40 years of experience is right  ;D).

Also be aware that the zero waste systems that route the concentrate back into your plumbing, in many (most) cases, this approach does not meet code.

Russ

Buckeye Hydro,

A very nice article. Below is one of the statements from the article. It is important to note that the reduction in EC/TDS is mainly done by the RO membrane. The sediment and carbon filters do not play as much of a role compared to the membrane. An RO membrane will last for a very long time but the sediment and carbon filters should be exchanged every 6 months.

When I first bought the system, I was accepting that I would be replacing filter sets every year.  After seeing the measured performance of the system, I would say that after 2 years, there does not seem to be a noticeable difference in output, so I would consider the filters still operating properly.

The sediment filter will remove the particulate that can clog the membrane. The carbon (GAC) filter removes odor and chlorine. If you are on city water then you will have chlorine present. With commercial RO systems the carbon is used to remove the chlorine so that it does not damage the RO membrane. The membranes have gotten better but I still see a lot of companies monitoring the water supply to ensure no chlorine goes to the RO membrane.

It would be difficult to monitor on a residential system so it would be best practice to replace at 6 months. Unless then carbon filter is a unique size I would not spend extra money on name brands. The canisters used in residential systems tend to be a standard size.

It is not unusual to see TDS creep up on storage. I have seen on mixed bed DI systems for 18 megohm water. Once the water is flowing the resistivity will increase from 10 to 18 megaohms. I would think it is from carbon dioxide forming carbonic acid that would disassociate into hydrogen and bicarbonate ions. Not sure how the atmospheric CO2 gets in the water in a sealed system. Either way as you use the system there will be a little change.

Side note for people with an RO system and no EC/TDS meter. Definitely worth the money for an inexpensive tester. If a membrane gets a tear then the output will be the same as the input and the membrane has to be replaced.  It is one of those things that you will not know unless you measure another parameter (hardness, chlorine, iron, etc) as an indicator the membrane is no longer functioning.

I have a watts system and they claim that the membrane only needs to be replaced every 2-5yrs… I’ve found that its more like 12-18months… I’ve never been 100% happy with the system and would have a hard time believing that any membrane will last 2+yrs. We have hard water here and I know that plays a role but I don’t think its that bad. Getting a testing meter would probably help me figure out more what’s going on with the system.

The raw water quality has almost everything to do with membrane life and performance. Most membrane manufacturers indicate that their membrane should last about 3 or more years. However, the raw water quality can easily reduce that by causing excessive or premature scaling on the membrane. People that live in areas with elevated silicate concentration are particularly susceptible to early membrane clogging.

If you are experiencing short membrane life, that suggests that either a flushing system is needed or the wasting rate for the system needs to be increased.

The most important thing to understand is that you don’t need to replace any filters or membranes on a schedule. There are ways to monitor the performance and viability of any of those components and you can make an informed decision as to when replacements are actually needed.

Agree, Martin.  I have had a Clearwater Systems K5 RO system here for at least three years.  We replaced our water softener this spring and the rep. checked the RO for TDS etc.  The TDS level was around 20 which is excellent given the crappy water we have coming our of our well (e.g. 400 grains of hardness, a high amount of TDS, and black manganese).  So the membrane is still good it just needs the two filters replaced, one on the input and one on the output occasionally (around every 3-5 months depending on water usage.  There is an indicator on the unit that lets you know when they need replaced.

As a part of the sale of the water softener, they included a new K5 R.O. in the package which is sitting in a box in my garage and I am trying to sell on Craig’s list.