Conserve double the water on your RO system

[FreshReefer]

I have been doing a lot of research about how to conserve water from my RO system. I realized I was using 4 gallons of filtered water per day.

This means I am wasting 16-20 gallons of water per day on the RO just to evaporation.... WOW!!

So the rejection rate was between 1:4 and 1:5 for my RO system. This is about average. By purchasing a second membrane and cartridge and plumbing the waste from the first membrane into the inlet of the second I was able to get the rejection rate down to 1:1.8 or so. so now I am down to 6-9 gallons per day of waste and nearly doubled the rate that I can produce water.

In this time where water is scarce in our neck of the woods I would urge everyone to consider this. I didn't do the calculations on the money savings, but the cost of the upgrade is only $50 or so.

If you want to know more let me know.

 

[lokii_37]

I've been thinking of doing this for awhile but have not pulled the trigger yet.

Do you run the water from both membranes through the same DI? I was thinking I could T the membrane outputs into 1 DI.

 

[FreshReefer]

Yes same di.

 

[woodnaquanut]

I've been thinking of doing this for awhile but have not pulled the trigger yet.

Do you run the water from both membranes through the same DI? I was thinking I could T the membrane outputs into 1 DI.

Yep, that's the way it works. BRS has a clear video of the conversion process.

I've been mulling it over too. Sounds like its group buy time! Let me know if you want to combine orders. BRS kit is $60

 

[cbrennan4]

Yep, that's the way it works. BRS has a clear video of the conversion process.

I've been mulling it over too. Sounds like its group buy time! Let me know if you want to combine orders. BRS kit is $60

I'm interested in purchasing one!

 

[1kwksvt]

I might be in on that group buy

 

[Xx YOZER xX]

I may be in as well... I've been feeling guilty about wasting so much water

 

[lokii_37]

I could do that too

 

[Dragonvale]

I thought I heard from someone that you have to have a certain PSI to get through both membranes. So this individual had to buy a booster. Just food for thought. GREAT idea. Following

 

[Retired Reefer]

I did that last year and it really helped. I'm also saving the waste water and using it for plants. PITA but it's what we've come to with this drought.

 

[FreshReefer]

Supposed to have 65 psi. Mine is 58 at the membrane and it worked great. You get even better efficiency with higher pressure, but that goes for a single membrane as well.

The higher pressure through the membrane causes more water through the membrane for the same flow rate of rejection...

 

[woodnaquanut]

If your pressure seems low and it's been a while since you changed the sediment and carbon filter elements, it's time for new filters!

These are the least expensive of the filters and replacing them improves (raises) the pressure to the RO membrane.

This of course also improves the efficiency of the RO membrane and might give you enough pressure to add the second membrane.

 

[lokii_37]

When I looked at BRS the kits say they only need 50psi at the first membrane to run efficiently.

 

[1kwksvt]

Where I am at my water pressure is 65 psi

 

[Cheko_dad]

I was just at the water store today to get a new RODI system to replace my old one and asked them there about just this ideal. They advised agenst it since the waste water from the first membraine would be so dense with just that waste it would only end up plugging the second membraine all that much faster and needing to replace it sooner. The cost of more water or new membraines sooner what would be the more costly?

 

[FreshReefer]

At $26 for a 75gpd filmtec membrane I was fine with it to double the production. Also the secondary benefit was to conserve water which appears to have become abundant all of a sudden..... Still the TDs meter shows water in to the second membrane only 50ppm higher or 340ppm for me. The point is, most off the water passes through the filter and never even goes near the membrane.

There is also some new technology out there for forward osmosis which looks promising.

I can believe how fast I can fill 2 brutes now.

 

[lokii_37]

I think about it like this: just so the numbers work out a little easier say your incoming was 200ppm TDS. If you have a 1:4 good to waste ratio you will only see a 20-25% increase in the TDS at the second membrane, about 240ppm.

Yes the second membrane will get used up faster but it will be worth the $26. When I get mine I will move the old membrane to the second RO and put the new one in the first RO. That way I can cycle the membrane thru.

 

[woodnaquanut]

Also the secondary benefit was to conserve water which appears to have become abundant all of a sudden.....

Don't get fooled by the current downpour! SR typical rainfall thru January is 17+ inches. Right now we are at 6+ inches. So we need 11 inches MORE to just get to January amounts.

The drought is still here, it's just a bit more moist than it was a week ago!

Best local rain gauge I've found is at:
http://ci.santa-rosa.ca.us/departments/utilities/stormwatercreeks/weather/Pages/default.aspx

 

[NeonFish]

how much water does the county dump in the oceans? I realize it is for safety, but I think they should just give free water rather than dumping into the ocean. then at least it goes into the water table.

 

[FreshReefer]

Believe me I am well aware of the situation. This will be the first year I can remember I have been able to drive to our family cabin in the sierras without cross country skiing or snomobiling. As in I can drive right to the front porch even after this storm we just had...