ro water saving idea

[jdieck]

Good test fahz. Are you able to read the pressure at the inlet of membrane 1 and in beteeen membranes? By the TDS readings you may try a little less restriction and see if TDS improve.
That say that at least with booster pumps or good input pressure water can be saved and confirms the need to replace DI more often, I think the lingering question will be if the membranes will deteriorate faster and how much of that effect if any can be prevented with good back flush which will be more difficult to answer.
As a membrane can last from usually 3 to 5 years, which is a large range of variability, reaching a conclusion only based on how long it lasted will not be conclusive. Unless we test running two systems in parallel continually measuring rejection rate, that question will remain for quite some time I guess.

 

[fahz]

Just to clear a few things up our tap water is much colder then the 68 degrees I tested with. It comes in at 54 degrees but I use a mixer valve to rise the temp. My house pressure is only 40 psi so I need the booster and I am unable to test with say 60 psi. I may have to run a bypass to see what this will produce at 60 psi. Someone asked me about making one of these a few months back but he wasn't ready yet he wanted to replace a AWI Eskimo. I should have made a test model at that time. He really can just replumb his Eskimo and doesn't need to replace it.

I have run a single 75 GPD menbrane at 100 psi for two and a half years and produce on average 100-150 gallons per month of production water. I see no adversed effect on the membrane but our sediment level is very low. A 5 micron sediment filter looks almost white after 8-12 months.

jdieck do you also have low pressure or any idea what your system would produce without the booster? I will add some pressure gauges today and get some reading.

Jim

 

[jdieck]

<a href=showthread.php?s=&postid=7565776#post7565776 target=_blank>Originally posted</a> by fahz
Just to clear a few things up our tap water is much colder then the 68 degrees I tested with. It comes in at 54 degrees but I use a mixer valve to rise the temp. My house pressure is only 40 psi so I need the booster and I am unable to test with say 60 psi. I may have to run a bypass to see what this will produce at 60 psi. Someone asked me about making one of these a few months back but he wasn't ready yet he wanted to replace a AWI Eskimo. I should have made a test model at that time. He really can just replumb his Eskimo and doesn't need to replace it.

I have run a single 75 GPD menbrane at 100 psi for two and a half years and produce on average 100-150 gallons per month of production water. I see no adversed effect on the membrane but our sediment level is very low. A 5 micron sediment filter looks almost white after 8-12 months.

jdieck do you also have low pressure or any idea what your system would produce without the booster? I will add some pressure gauges today and get some reading.

Jim

I am planning in running pressure tests over the weekend. My tap pressure is 60 psi during the day and drops to 40 after 10:00 PM. until about 5:30 AM in winter it is around 45 psi all day long. Seems the city service turns some equipment off during spring and summer, irrigation is on between 6:00 and 10:00 AM and PM but I have not noticed drops during that time.
Because of the pumps by-pass pressure regulator despite the change from 40 to 60 the pump maintains 70 to 75 psi to the membranes regardless of whatever the pressure drop is troough the sediment and carbon filters (The pump is located after sediment and carbon before membrane 1).
This weekend I want to take measurments of pressure at inlet of system, at inlet of membrane 1, in between membranes and after membrane 2 before restrictor with and without the booster pump.
I will also try to test rejection of the individual membranes and see the difference although membrane one is 3-1/2 years old and the other is about 18 months old.

 

[northbay-reefer]

<a href=showthread.php?s=&postid=7565942#post7565942 target=_blank>Originally posted</a> by jdieck
I am planning in running pressure tests over the weekend. My tap pressure is 60 psi during the day and drops to 40 after 10:00 PM. until about 5:30 AM in winter it is around 45 psi all day long. Seems the city service turns some equipment off during spring and summer, irrigation is on between 6:00 and 10:00 AM and PM but I have not noticed drops during that time.
Because of the pumps by-pass pressure regulator despite the change from 40 to 60 the pump maintains 70 to 75 psi to the membranes regardless of whatever the pressure drop is troough the sediment and carbon filters (The pump is located after sediment and carbon before membrane 1).
This weekend I want to take measurments of pressure at inlet of system, at inlet of membrane 1, in between membranes and after membrane 2 before restrictor with and without the booster pump.
I will also try to test rejection of the individual membranes and see the difference although membrane one is 3-1/2 years old and the other is about 18 months old.

JD, check to see if your house have one of these installed at the main line, if you do, all you have to do is turn the screw on this device, notice it has 3 pressure levels, turn the screw clockwise will release the valve and increase the pressure of the water entering your house. I cranked mine to the second level and got 75-80 psi to my house water line and it had works so much better wiht my RO system.

[/IMG]

 

[Vincerama2]

<a href=showthread.php?s=&postid=7562070#post7562070 target=_blank>Originally posted</a> by Savatage
Let us look at something else here. Lets go back to the beginning of this thread. Put this one on the scales and weigh it out once..........

Which one costs more. Water or resin? If we disconnect our RO and run straight to the DI, we have no waste water. In the long-term are we spending more on the water going down the drain or on the resin?

The only real question that concerns me is, how would this effect the TDS difference???? Does the RO unit remove the TDS or does the DI part remove the TDS?

Lets talk about this idea for a while. Give us pros and cons on this one. I think it's the best way to go because of this reason...... Anthony Calfo (if I'm not mistaken) only runs a DI and no RO. He has had no problems that I know of. I only wish we could get him in on this thread.

I'm with you...this thread is now highly confusing to me! But fun to watch the discussion! I think for us laymen hobbiests, the best thing is to stick with the RO units we have and try to use the waste water in some way that we won't actually waste it, like watering plants or doing laundry.

Someone in our (Bay Area Reefers) club tried to go DI only with some Spectrapure resins. I believe he was using colour changing Cation and Anion resins in seperate water filter housings and found it was just easier to just use RO. I think if you get the regenerable resins you can regenerate them using stuff you can buy at HD.

I also agree with the water experts here that if a more efficient and economical way of doing this were out there, it would likely already be used/tested by the "industry".

And speaking of "waste" for DI only units... dont' the chemicals used for recharging the resin; a) cost money (more than the wasted water?) and b) create their own form of waste? (what do you do with used acid and bases? Toss them down the toilet??

V

 

[fahz]

jdieck there is really not much pressure drop. I have all the parts on hand so it's easy for me to run tests. The system drops 8 psi to the second membrane housing. I will build a bypass later today and see what 60 psi produces.

PSI with booster connected directly to tap 96 psi

After filter housings 5 micron poly sediment,
12 x 40 mesh GAC chloramine, .5 micron carbon block 90 psi

After first membrane housing 88 psi

 

[jdieck]

<a href=showthread.php?s=&postid=7566144#post7566144 target=_blank>Originally posted</a> by northbay-reefer
JD, check to see if your house have one of these installed at the main line,

Nbay:
No regulator in my case.

 

[jdieck]

<a href=showthread.php?s=&postid=7566400#post7566400 target=_blank>Originally posted</a> by fahz
jdieck there is really not much pressure drop. I have all the parts on hand so it's easy for me to run tests. The system drops 8 psi to the second membrane housing. I will build a bypass later today and see what 60 psi produces.

PSI with booster connected directly to tap 96 psi

After filter housings 5 micron poly sediment,
12 x 40 mesh GAC chloramine, .5 micron carbon block 90 psi

After first membrane housing 88 psi

Thanks for the test. That is a 2psi drop in pressure across the first membrane (assuming the precision of an standard gauge that could be +5 but still low enough as my initial numbers assumed. Seems that systems with tap pressure below 60 might have trouble getting the rated capacity out of the second membrane if it has to run in the mid 50s after the pressure drop from the sediment and carbon filters although not many people uses 0.5 micron filters.
I'll also try to simulate different tap pressures via needle valve restriction and see what the data show.
I am wondering for those cases if a permeate pump (which is cheaper to install and operate than a booster) beteen stages could help maintain the rating in the second stage.

Did someone here mention pressure, pressure, pressure?

 

[fahz]

One problem with a permeate pump is it also requires a pressure water tank so you getting close to a booster price.

Jim

 

[fahz]

Cati/ Ani DI systems work but have some pit falls. You must use Muritic Acid and Lye in a 24 hour flush to regenerate. If your TDS is in the 200+ range you will produce about 12 gallons of waste flush water before producing about 40 gallon of production water before regeneration again. The chemicals can then be mixed and are rendered nutural so they are safe to flush down the toilet.

I tried the two membrane in series system last night and cut the waste my system produces from 720 gallons to 225 to produce 180 gallons of pure DI water.

Jim

<a href=showthread.php?s=&postid=7566186#post7566186 target=_blank>Originally posted</a> by Vincerama2
I'm with you...this thread is now highly confusing to me! But fun to watch the discussion! I think for us laymen hobbiests, the best thing is to stick with the RO units we have and try to use the waste water in some way that we won't actually waste it, like watering plants or doing laundry.

Someone in our (Bay Area Reefers) club tried to go DI only with some Spectrapure resins. I believe he was using colour changing Cation and Anion resins in seperate water filter housings and found it was just easier to just use RO. I think if you get the regenerable resins you can regenerate them using stuff you can buy at HD.

I also agree with the water experts here that if a more efficient and economical way of doing this were out there, it would likely already be used/tested by the "industry".

And speaking of "waste" for DI only units... dont' the chemicals used for recharging the resin; a) cost money (more than the wasted water?) and b) create their own form of waste? (what do you do with used acid and bases? Toss them down the toilet??

V

 

[AnnArborBuck]

CATI/ANI systems alone will not remove everything that a RO unit will. Only charged particles will be removed by the CATI/ANI system, where as the RO filter goes off of particle size. So anything such as bacteria that is not charged will not be removed by the CATI/ANI system as they won't be attracted . It really is best to run RO and a CATI/ANI system.

 

[Wryknow]

I have a DI only unit and it gets the PPM down to the 0-4 ppm range when its properly charged. It has a carbon block first stage to remove particulates like chlorine, etc. The water quality is better than that of the RO only unit at my fav LFS IMHO, which produces water in the 8 - 10 ppm range pretty consistently. My total chemical cost to make water is $.068/gallon. I also need to replace the carbon block filter every 1000 gallons. The best part is that it produces water very quickly (200 gal/day flow rate) with no waste water IMHO.

 

[Roland Jacques]

<a href=showthread.php?s=&postid=7566186#post7566186 target=_blank>Originally posted</a> by Vincerama2


I also agree with the water experts here that if a more efficient and economical way of doing this were out there, it would likely already be used/tested by the "industry".

No offence man. And most people would probably agree with you, But, that is by far, the most wrong thing you can possible say, in this Do It Yourself forum. Their are pages after pages of improvements here on RC that blow away “the best products in the industry’s". You don’t have to look hard to find them. I for one think you have conclusively seen it proven again right here and now.

We don’t have to follow the industry. look at some of the occupations of these members, the industry is here, listening and following us. IMO

 

[AnnArborBuck]

<a href=showthread.php?s=&postid=7567023#post7567023 target=_blank>Originally posted</a> by Wryknow
I have a DI only unit and it gets the PPM down to the 0-4 ppm range when its properly charged. It has a carbon block first stage to remove particulates like chlorine, etc. The water quality is better than that of the RO only unit at my fav LFS IMHO, which produces water in the 8 - 10 ppm range pretty consistently. My total chemical cost to make water is $.068/gallon. I also need to replace the carbon block filter every 1000 gallons. The best part is that it produces water very quickly (200 gal/day flow rate) with no waste water IMHO.

TDS is not the end all be all. Not everything in your water is accounted for in the TDS measurement. TDS is a great number to use as a basis, but again, TDS does not measure everything in your water.

 

[Roland Jacques]

<a href=showthread.php?s=&postid=7567023#post7567023 target=_blank>Originally posted</a> by Wryknow
I have a DI only unit and it gets the PPM down to the 0-4 ppm range when its properly charged. It has a carbon block first stage to remove particulates like chlorine, etc. The water quality is better than that of the RO only unit at my fav LFS IMHO, which produces water in the 8 - 10 ppm range pretty consistently. My total chemical cost to make water is $.068/gallon. I also need to replace the carbon block filter every 1000 gallons. The best part is that it produces water very quickly (200 gal/day flow rate) with no waste water IMHO.

im doing the same right now but my costs are a lot higher than yours per gallon. are you counting the time to regenerate or do you just have a good source to buy DI? that why im here trying to get set up better with water

 

[AZDesertRat]

As mentioned already a DI only unit will not remove everything that a RO/DI does. In order for DI to work things must be positively or neagtively charges so they attract, if they are not they don't get removed. Yes activated carbon will remove chlorine and some volatiles but other things including viruses and bacteria might pass through as you do not have an absolute barrier like a good RO membrane provides.

 

[fahz]

yourfishman don't you have fairly low TDS in your tap water in Atlanta like in the 60's? Also good to have another Kati/Ani man in the discussion.

wryknow glad you could join us I didn't want to use your PM information with out your OK. You have first hand information on Kati/Ani DI Which is far better then here say.

For everybody let's try to keep this on a civil level as there is some real worthwhile information being shared here. Waste water is a big issue that we receive questions about everyday.

Jim

 

[Wryknow]

I agree that a TDS reading is only what it is. It is certainly not a perfect measurement of all possible contaminants. It's pretty convenient though and does convey some useful information about water quality. If anyone has access to better testing facilities I would be more than happy to send a water sample for testing as I want to know what's going in to my aquarium at least as much as anyone else does.

I would argue that there are very few contaminants, and none that I need to worry about practically speaking, that have absolutely no charge what-so-ever though. I do agree that an RO membrane in combination with DI would be better that DI only if your goal is absolutely pure water. The DI only seems to work for me though. My TDS goes from 270 out of the tap to 0-4 after the DI so it's removing the vast majority of anything other than water.

Obviously, the 200 gpd does not include recharge time as I recharge at least one of the resins every 40-50 gallons or so. The high gpd rating does mean that I can hook the system up and generate enough water for a 25% water change and a couple of weeks worth of top-off water in one evening. I can just hook it up to the kitchen sink when I need to and my wife doesn't have to look at it the rest of the time. It takes me about 5 minutes to set-up the recharge drip system when I'm finished.

My costs/gallon are based only on the chemical costs. I use the lye to recharge every time and that costs about $15 a bottle from Lowes and I get at least 8 recharges from a bottle. At 40 gallons per recharge that's about $.0468 per gallon. The muratic acid runs me about $8 a bottle and I only get 3 recharges per bottle, but I only need to recharge it about a third as often as I need to use the lye. At 120 gallons per recharge that costs me about .0222 per gallon. So I guess it's more like $.069 per gallon for chemicals.

Jason

 

[Wryknow]

Oh yeah - the chemicals are certainly not safe before or after recharge so keep that in mind if you are considering a rechargable DI system. The lye mixture is still very useful for drain cleaning though (that's what it's sold to do after all) so I alternate drains in my house and give them a good preventative cleaning periodically. The muratic acid can still be used to clean but it is significantly less potent after doing the recharge.

 

[fahz]

Here are more results at lower pressure readings and without a doubt the waste water savings are eye opening. I could not get a good psi reading before the filter housings because of needle flutter.

Jim

TEST RESULTS 65 PSI ENTERING FIRST MEMBRANE

Two 75 GPD Filmtec membranes in series
One 75 GPD 600 mL flow restrictor
Aquatec 8800 Booster pump producing 96 psi
Tap water temp 64 degrees
Tap water TDS 59 ppm
TDS entering DI 2 ppm
DI water TDS 0
Production water 1 gallon 10:45 minutes
Waste water 6.5 quarts
Production water 5.58 GPH or 133.92 GPD
Waste water 9.07 GPH or 217.62 GPD


GALLONS OF WATER SAVED 318



TEST RESULTS 60 PSI ENTERING FIRST MEMBRANE

Two 75 GPD Filmtec membranes in series
One 75 GPD 600 mL flow restrictor
Aquatec 8800 Booster pump producing 96 psi
Tap water temp 64 degrees
Tap water TDS 59 ppm
TDS entering DI 2 ppm
DI water TDS 0
Production water 1 gallon 11:45 minutes
Waste water 7 quarts
Production water 5.11 GPH or 122.64 GPD
Waste water 8.94 GPH or 214.62 GPD

GALLONS OF WATER SAVED 276