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RO System for Fiver - Questions?


RandyA

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Sorry if this seems OT here, but a recent comment on Steve D's thread about helping to spend his money for his new Space Craft got me wondering.

 

I have a small (10 gallons daily) Reverse Osmosis system I installed exclusively for the drinking/coffee/tea/ice-maker hooked to a water faucet next to the sink. I did this primarily to cut down on plastic water bottle use and to filter out any organisms in an unknown CG water supply that might be unhealthy. I also use an automatic shut-off valve and a flow restrictor going to drain on my RO system.

 

Our whole house RV water supply passes through a carbon/coconut pre-filter, then to a salt based water softener and then to another post filter of about 5 microns. We do this, of course, to remove any sediment and soften the water for bath/shower/washer/dishwasher and longevity of the hot water tank. I thought I was in good shape water wise.

 

Then, Jack made a suggestion on Steve's thread: "Whole house RO, but NOT the drinking water. Plumb the kitchen direct from the filter complex on shore water. That way you are drinking water that has minerals in it. You can use a Berkey filter if you want to process it more. I would. You can build the Berkey gravity water system into a cabinet if you want with a fill tap at it....that would be real custom."

 

OK - that's not what I am currently doing. I highly respect Jack's knowledge on many subjects - this being one.

 

So, I looked up Berkley Filters. It appears that these are freestanding pot filters that you need to manually fill with a pitcher (unless you add the above fill tap) and dispense water from a spout like on a commercial coffee pot. Am I correct?

 

Then, learning how well the Berkley filter removes even the smallest organisms that could make you sick I think that it would also remove most if not all dissolved minerals as well - minerals are right down there in size with bacteria. Again, is my thinking correct? If not, how does it differentiate?

 

We know RO will remove minerals. But basic minerals needed for your body can come from diet and once-a-day supplements taken orally like a vitamin with minerals. I'm thinking that RO for drinking water is OK if you follow the above rule - yes or no?

 

Now, here is a BIG one: RO units produce a considerable amount of waste water that goes down the drain. I have my waste water line plumbed into a vacuum breaker that goes to the gray tank and have a "T" in the drain line so I can divert RO waste water outside into a bucket for later watering flowers or a tree or even bring it back inside to flush the potty when NOT on city water. What size RO system would be needed (including storage tank) for a whole house RV water system? How much waste water would it generate? It seems to me that having anything but storage of RO water would quickly deplete an on-board potable water supply and if run to the gray drain it will work to fill the holding tank quickly (80 gallon total capacity - 2x40 on my fiver). As is, I cut off the RO water supply when dry camping, traveling or anytime I use RV tank water and just use what the RO storage tank holds to avoid waste water draining from membrane flushing.

 

Space in an RV is an issue to me, especially counter and cabinet space. The Berkly would gobble up one or the other and a larger RO storage tank (mine is about 2 gallons and fits perfectly in a unused corner of the basement) could further reduce needed storage space. What size RO tank is needed for a whole house RV system? (yea, asked that above too)

 

These are honest to goodness valid questions to me. I thought I was doing it right, but now I am not sure and also wondering about the "HOW?" if I should decide to change anything. I am not a water filtration expert by any measurement and would appreciate any or all comments about RV water filtration systems that are being used and the need for whole house RV RO water systems. (My questions may appear Off Topic but I consider the HDT to be an integral part of the fiver and besides, I have found those who frequent this thread are extremely knowledgeable on a broad base of RV subjects - not just HDT's - often more so than other threads :) ) So, what are others doing and how well does it work for you?

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If you're going to fill your main water tank with RO water then you have no choice but to direct the RO waste to a waste holding tank.

 

If you're filling a second tank just for drinking then send the RO waste to your fresh water tank. There isn't anything wrong with RO waste for general water use. The waste just has a higher mineral content but it's still the same water that feed the RO membrane. That way you don't wast any water.

 

In either case if you want to reduce the amount of waste then use two RO membranes. Feed both the RO outputs to the RO tank and feed the second RO membrane from the waste output of the first RO membrane. This will reduce the waste from 75% to 50% and double the production rate. This makes the most sense if your filling your fresh tank with RO water but is not really necessary if you're sending the waste to your fresh water tank.

 

All of this assumes that your are filtering all incoming water to a lever that removed any harmful bacteria but you should be doing that even if you just shower in it.

 

IMHO

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Randy, HERE is the design document for my whole house RO system.

 

The issue you have to watch out for with RO is acid water. In some situations it will produce water that has a PH that is probably too low for good , continuous, drinking water. There are things you can do to resolve that, if necessary. I monitor my PH and in over 2 years with the whole house system I've not had any real issues.

 

It DOES waste a considerable amount of water. It is not something you are going to use boondocking, so you need to plumb a bypass system for it. I generally get 35-45% good water when processing.

 

Now, for those that will say I'm ruining the environment....I use between 20-30 gallons of water a day. And yes, I measure it. So although I "waste" some water - actually a considerable amount, percent-wise - it really is not that much compared to a house, or even most people in RVs.

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And to think we use our ground water well, filter it once, run it through a Morton softener and drink it. ( and use it in the 5 'r ..... Aint got sick once, but since the ends of my fingers started glowing I don't need key lights either..... Life is good,,,,,

 

All kidding aside, we do watch what and where we put on a load of water. Most muni water is pretty good. and in 3 yrs. we've had to change the selector valve due to corrosion and just use.

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If you're filling a second tank just for drinking then send the RO waste to your fresh water tank. There isn't anything wrong with RO waste for general water use. The waste just has a higher mineral content but it's still the same water that feed the RO membrane. That way you don't wast any water.

 

Now that is something I had not even thought about doing. I guess the word "waste" automatically made me think it was bad water. But, now I see it is not bad, only higher in minerals. If I am boondocking and using water from my main storage tank (80 gallons) this mod would solve a lot of issues. THANKS!

 

The system shown in this stock photo is what I have for my drinking water RO system. Jack, I am going over your design. Might have some questions later. Thanks for the reply.

post-12482-0-65235100-1479600704_thumb.jpg

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My opinion is that getting minerals and vitamins naturally is always better than via supplements. Studies continue to show how we know little about how nutrition is absorbed by our bodies so why not hedge a little and eat and drink the real thing?

 

We use a Berkey (1-2 gal size) which fits easily by our sink and provides all our drinking and cooking water needs. The reason it is so efficient at filtering out the bad and keeping the good mineral is due 1. to its proprietary filter media design, and 2. it filters slowly using gravity only. This allows the media to do its job and for the transfer of good minerals (no heavy metals). The bacteria, for example is captured by the media and trapped. Minerals dissolve and move through the media over time. We also have the additional Fluoride and Arsenic filters. To dissolve minerals into water takes time which is why the "re-mineralization" filters offered for RO systems operating inline under pressure don't do a good job of putting healthy minerals back into the purified water supply, although they can positively affect on PH and taste.

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Now, for those that will say I'm ruining the environment....I use between 20-30 gallons of water a day. And yes, I measure it. So although I "waste" some water - actually a considerable amount, percent-wise - it really is not that much compared to a house, or even most people in RVs.

I'll take the opposite perspective: water isn't "used", per se, it's merely ripe to be polluted. Putting RO waste water back into the environment is far less harmful than industrial byproducts, soaps, medicines, etc. I'm amazed at how many municipal water customers think they're getting "fresh" water: many are getting water from other municipalities upriver that are treating the waste and returning it to the river to be sent downstream. It's the people who water a southern lawn at high noon, resulting in massive evaporation, who are disturbing that "catch and release cycle" by introducing humidity that'll travel much farther away than the river's natural flow.

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Randy, for our rig I use 3 filters before water gets into the tank. First a cheap Camco inline to extend the life of the second filter which is a 5 micron sediment unit, then a 1 micron carbon block filter. Then for drinking/cooking we use a 2 gallon Berkey unit. We've run Berkey's at home and on the rig for about 7 years and like them. I don't see any huge need for an RO system for us.

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The reason I really like the RO system is because it extends the life of all of my water-based fixtures and appliances. And saves me servicing the toilet....at least some. Plus I don't have to clean the clear walled shower. It really makes a very significant difference in those areas.

 

I like the idea of the Berkey filter system for drinking water. I'll likely go that route in the future. RO for everything but my drinking water. That will be supplied off the Berkey.

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I'll take the opposite perspective: water isn't "used", per se, it's merely ripe to be polluted. Putting RO waste water back into the environment is far less harmful than industrial byproducts, soaps, medicines, etc. I'm amazed at how many municipal water customers think they're getting "fresh" water: many are getting water from other municipalities upriver that are treating the waste and returning it to the river to be sent downstream. It's the people who water a southern lawn at high noon, resulting in massive evaporation, who are disturbing that "catch and release cycle" by introducing humidity that'll travel much farther away than the river's natural flow.

I basically agree however RO "waste" is not contaminated it has exactly the same as it had when you started but with a little less H2O. The waste from recharging a water softener is simulat except it has a lot of sodium added to what was already in the water which is why you don't use softener wast for plants but you can use RO water for plants. Actually there is nothing wrong with just dumping RO waste on the ground other than leaving a big wet spot.

 

Water is always water. All that's being done with either RO or a softener is the removal of any impurities and leaving the water. Are those impurities bad? Well maybe yes, maybe no or just maybe just something that messes with your plumbing.

 

What's the best system to use? I don't know but I'm leaning toward filling the tank with water that's been run through good filtering and a softener and then use carbon filters and a UVC sterilizer on any water coming out of the tank and then RO the drinking water. Water will always be used from the tank and never directly from the street so you always operate in a controlled environment.

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What's the best system to use? I don't know but I'm leaning toward filling the tank with water that's been run through good filtering and a softener and then use carbon filters and a UVC sterilizer on any water coming out of the tank and then RO the drinking water. Water will always be used from the tank and never directly from the street so you always operate in a controlled environment.

That is a decent strategy, just be sure to UV the drinking water from the tank (as you suggest). Since it is sitting exposed to air one could argue that it is not as "clean" as you might like. I'd simply put the UV lamp on the output of the RO system in your scenario.

 

I have provision in my system for a UV lamp, but to date have not installed it. To me the major benefit of the RO water is not the "pure" drinking water part....it is the overall benefit of water with low particulate matter in it - especially minerals. Much of the water where I frequent is quite "hard" and it really messes up the fixtures and toilet in an RV. In your scenario you do not gain that benefit. We live in our coach, so part timers may not benefit at all from the elaborate steps I've taken.

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Jack, How do you configure the UV lamp at the output? How long does the water need to remain under UV light to benefit? Will the UV light be of any benefit to flowing water at say 2.8 to 5 gpm?

 

BTW - our ice maker is a portable unit. It has two sensors in the water flow path that determine if the water tank is empty. If the mineral content of the water is non-existent, like with distilled or RO water, there is not enough conductivity between the sensors when the water is flowing and I get an "out of water" error and the unit cuts off. I ended up having to short the sensors together to make the ice maker work. On the subject of forgetting, we must now remember to check and refill the ice maker water tank daily. If I get rich one day, I will have a big refrigerator with a built-in ice maker.

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