REVERSE OSMOSIS

[Doofy]

I have a hand dug shallow well with hard water, manganese and some clear water iron. TDS runs about 400 ppm for raw water. TDS drops to about 80 ppm after the R/O.

 

[coobie]

Had a Kinetico brand reverse osmosis installed about 2 years ago and we really like it.We change 2 filters once per year cost is $20 bucks each.System was not cheap around $1,200 bucks installed..We used to get 4 of the 5 gallon coolers filled once every few weeks.Getting a little older and they were a little heavy to tote.LOL..

 

[Coyote machine]

Good questions....yes, I certainly should have mentioned goals first. My goal for the RO was to reduce dissolved manganese and sulphates in our drinking water. Both of these are natural to our mineralized water and within the normal limits - but on the high end and I imagine I can taste them sometimes.

So that is why I was put a simple undersink RO system for our drinking/cooking water.

And come to think of it, I should explain our system first. It's probably not that different from other rural systems.
Our well is a shallow well into a sand and gravel deposit a few hundred feet from a mountain stream.
So the source water is similar to that of a natural spring - but it still requires a pump to bring the water uphill to the house.
House pressure varies between 20 and 50 psi, so the pressure should be sufficient for RO.

At the house the water is treated to several stages of screen & paper filtration followed by charcoal filters (in parallel) & a commercial UV anti-bacteriological system (Atlantic UV, Sanitiron). All real standard stuff from Home Depot - except the UV, which is a commercial size.
We also "shock-chlorinate" the well twice a year, and pay to have a water analysis done on the product water about every few years - or if anything changes.

Last fall I added a simple GE undersink RO with its own faucet. It seems to work. Our basic water tastes good, but the RO seems to taste slightly better. So I was happy until I sent a sample to the lab for testing a few months later, I was surprised to find how much the RO water varied from the well water. Well water analysis remains the same, and in the RO water the mangaese was down sure enough. But the RO water was higher in some other things - including sodium & total dissolved solids (TDS). I wonder why? The lab had no idea, and they were surprised. They even re-ran another sample for free.

So that's when I realized I didn't actually know that much about RO systems. According to the lab director, there is no way that an RO system could fail to lower the sodium and TDS. And so that is why I posted here.
What do others find when they do a water analysis on their drinking water?
rScotty

Sounds like your simple GE RO isn't working. Have you contacted them about your lab results? Did you do the proper protocol for sterilizing the RO's spout prior to collecting the sample water to be lab tested? How much time lapsed between collection and lab test?

 

[Egon]

Sounds like your simple GE RO isn't working. Have you contacted them about your lab results? Did you do the proper protocol for sterilizing the RO's spout prior to collecting the sample water to be lab tested? How much time lapsed between collection and lab test?

I'll agree. Something is not right.

 

[rScotty]

Sounds like your simple GE RO isn't working. Have you contacted them about your lab results? Did you do the proper protocol for sterilizing the RO's spout prior to collecting the sample water to be lab tested? How much time lapsed between collection and lab test?

These are inorganics, so sterilization isn't an issue. I'm pretty good at technical things; the samples were collected in a careful manner. There's no way to know what happened at the lab - so there's one possibility
I haven't been able to reach anyone at GE - or at several other companies - who is both able and willing to discuss their RO.
Frankly I'm learning more by discussing it on TBN.

Here's the question I ask the RO people in technical sales:
Most of the RO systems offered have one or more pre-filters followed by the RO membrane, and that makes sense. But then most of them follow with another post-filter! (often charcoal) Now why would they do that? Why in the world would RO water benefit from being run through a post filter? It seems to me that doing that runs a risk of introducing particles plus any soluble impurities from the manufacture of the filter & charcoal in that final filter.
I wonder where that charcoal is made, and from what source?
Could that be the culprit?
So far, no answers. Just salestalk.
rScotty

 

[Egon]

Polishing filter is mentioned.

[video]http://www.agr.gc.ca/eng/science-and-innovation/agricultural-practices/water/ponds-and-dugouts/farm-surface-water-management/polishing-methods-distillation-and-reverse-osmosis/?id=1189697135106[/video]

 

[Ford850]

rScotty, It almost sounds like your RO hoses are reversed and you are drinking the drained water and flushing the clean water down the drain. I have no idea if that would be possible to reverse hoses like that, but it would explain the higher TSD from the RO unit.

 

[HillStreet]

rScotty,

Yup, I did a test after the system was put in and all is good, made a big difference.

The test before the system was comprehensive and cost $150. We did the test after the system (same test) and wouldn稚 you know it, it showed a bacteria. The installer and the lab said it was just bacteria from the truck or storage areas要ery common . So, we flushed the system and tested again and it is just fine. The latest retest was just $25. Living in Maine I thought the water would be like Poland Spring but no such luck. Water is good now, and it actually tastes good. Prior to the system, we had a bottled water system with a cooler, now we drink the well water.

 

[rScotty]

rScotty, It almost sounds like your RO hoses are reversed and you are drinking the drained water and flushing the clean water down the drain. I have no idea if that would be possible to reverse hoses like that, but it would explain the higher TSD from the RO unit.

DANG! Ford, that makes just too much sense. In fact, it made so much good sense that last night I got out the installation book and crawled under the sink with a mirror and flashlight and sketchbook ..... convinced that we had cornered the problem.

No such luck. All the lines are fine. In fact, they are color-coded and of different size so it would be very obvious if they were hooked up wrong. But just to double check, I made sure that I understood just why each line ran as it did. Unfortunately, everything is run correctly. Darn... it sounded like such a good theory, too.

Of course it could be an internal leak or crack in the housing, so I drained the RO tank and measured how long it took to re-fill. That's roughly in spec as well. Certainly it doesn't make RO water as fast as one would expect if there was an internal pressure leak from the house water into the RO system.
No success, but heck of a good idea! Thanks,
rScotty
,

 

[Ford850]

DANG! Ford, that makes just too much sense. In fact, it made so much good sense that last night I got out the installation book and crawled under the sink with a mirror and flashlight and sketchbook ..... convinced that we had cornered the problem.

No such luck. All the lines are fine. In fact, they are color-coded and of different size so it would be very obvious if they were hooked up wrong. But just to double check, I made sure that I understood just why each line ran as it did. Unfortunately, everything is run correctly. Darn... it sounded like such a good theory, too.

Of course it could be an internal leak or crack in the housing, so I drained the RO tank and measured how long it took to re-fill. That's roughly in spec as well. Certainly it doesn't make RO water as fast as one would expect if there was an internal pressure leak from the house water into the RO system.
No success, but heck of a good idea! Thanks,
rScotty
,

That's good you checked for a leak too, since that was my next suggestion. I guess it's a good thing you weren't drinking drain water all this time.

 

[Ford850]

This has been a good thread to learn about RO. I had no idea that RO produces only 10 - 25% and wastes the other 90 - 75% of the water it treats. Does that really mean people with whole house RO systems are dumping most of their water down the drain without using it?

 

[rScotty]

That's good you checked for a leak too, since that was my next suggestion. I guess it's a good thing you weren't drinking drain water all this time.

Well, I had some time to think about that and realized that even if I had, it would have been the same water that I'd been drinking for the past ten years before putting in the RO. I've got a call into GE's tech dept., hope I get the right person.
rScotty

 

[Doofy]

Age of membrane is also a possibility. Membrane could be fouled and unable to do its job.

 

[rScotty]

This has been a good thread to learn about RO. I had no idea that RO produces only 10 - 25% and wastes the other 90 - 75% of the water it treats. Does that really mean people with whole house RO systems are dumping most of their water down the drain without using it?

Not all of the systems dump the same amount of water, but all seem to dump some. The GE claims 10% flow efficiency; it is designed to dump 9.something gallons for every gallon of RO made. I've heard that some modern systems are more efficient. My guess is that a certain amount of waste water is necessary to flush the RO filter and maintain the concentration gradient...but that's just a guess.
Just as important is that the waste water flow be shut off when the RO tank is filled. The GE has a valve that does that, so the waste water doesn't continue to flow all the time.
BTW, I'm not convinced that the RO waste water has to be wasted. It's true that most of the systems are designed to put RO waste water into the outflow from the house right along with all the systems that dump or flush "used" water, but that seems to be plumbing convenience. I suppose it could be plumbed for watering plants or other purposes.
rScotty

 

[ScottyChip]

Hi rScotty
Great topic and I was going to suggest the same to check your lines for reversal, but since that is not a problem my next suggestion is that maybe your RO membrane is busted, or full of material and its efficiency is reduced and you are getting your system contaminated with the RO waste water. The membranes will fail or get plugged depending on the amount of material that has to be filtered. It is a very very fine sheet of material with really small holes on the microscopic scale that is wrapped around a central core that requires a high pressure to force your water through, then the contaminates that will not go through are washed away with water, hence the waste water.

I work in a analytical lab and we use RO systems to clean (polish) our city water so that we have no ions or contamination what-so-ever. Some manufactures of consumer systems will run the water through a charcoal filter or other type of filter after the RO membrane to add back in some of the ions removed to improve taste and as one person mentioned earlier to make it less corrosive (well it is not really corrosive, it is just that it has no ions and the pH is usually slightly below neutral or between 6-6.8), also the final filter will remove any VOC's (volatile organic compounds) they may be in your water. Softer water or water with lots of minerals and other ions will be harder on your RO membrane and it may need to be replaced earlier than suggested. The RO membranes in the consumer units is usually much smaller than the commercial units, but they both work the same way.

The other concern with RO systems especially for those of us on wells is the amount of waste water produced and the average system will waste 4+ gallons of water for every 1 gallon of water produced, hence why most people only treat drinking or cooking water and not the whole house. I would look at the systems you can get at your local Costco, Watts and Brondell, they both get good reviews, are relatively inexpensive and Watts offers the traditional and a zero-waste or their version of zero-waste which just dumps the waste water back to your hot-water tank so it can be reused as hot water. Not sure what happens to your hot water tank in the long term with all those extra minerals and other waste, but I am sure they would not be selling if these units if it caused long term problems. The other good thing about buying from Costco, is if you are not satisfied you just bring it back.

Hope this helps and this is a great discussion. I am looking to go down the same path as yourself, my well water has clear iron, and a number of other minerals. The reason I have not made the leap yet is the amount of waste water produced and potentially running my well dry. But really, I think I am being overly cautious, my well has good flow and capacity.

Scottychip.