another homemade ro hopefully it works!

[green4310]

I have the same(standard design)with a feed-back loop. Mine does 6gpm @200psi and 8% without feed back.
When feeding back to get a higher concentration, I lose gallon for gallon on the throughput.
I find it better(for me) to recirculate my feed tank if I want higher concentration, as I am boiling.
For bragging rites,I could get to 10% on a single pass also but I see no practical point. .
These things can get to be addictive also.
One other point is that these membranes are rated as
Max perm is 1.6gpm,
min conc. is 2gpm,
max concentration is 30%.
I have no idea how they will stand up to being driven into saturation.
Time will tell, I guess.
Anyhow kudos to all you DIY'rs

[Gary in NH]

The membrane ratings can really only be used for comparison in sap applications. When RO membranes are used for water treatment they are usually subjected to much higher mineral content and low organics (like sugars in sap). Raw sap has approximately 140 to 200 mg/l of dissolved minerals. It may go to 600 or 700 mg/l when recirculating. The maximum recommended recovery % for water is based on the potential for minerals to over-saturate and foul the membrane. There is an index called the Langlier Saturation Index (LSI) to determine at what recovery percentage the membrane will foul based on a complete water analysis of cation and anions in the water. When using an RO membrane for sap all the specs for water are ignored except the GPD rating, rejection and maximum pressure. Since the membrane is concentrating sugars which are organic membrane cleaning is needed to keep the membrane from organic and bacterial fouling because it is operated so far out of typical design criteria established for tap water.

[wcproctor]

Wow! What is the final cost to you to build this? look like something I would like to make.

[green4310]

Thanks Gary, Thats good info. I just started pushing my 270s to 4.8p/1.2c @ 200psi, with no ill effects the last 300gal or so. I have around 500gal to do right now, so here goes.

[green4310]

A single membrane unit like Waterguys could easily be built for $1100.

[markct]

green4310, do you have any info on sources for the parts to build such an ro, im realy considering setting up something like that for next year, but maybe a touch bigger like 2 membranes

[arcticmaple8]

Well i have been looking into it further. I am feeding pressure from my holding tank with a wayne sprinkler booster pump with 1" plastic pipe, then through 1" house filter, then into my procon series 4 pump with 3/4 hp motor. I am getting about 220-240 psi which goes into membrane, then out of membrane to a tee. One side of tee goes to gate valve which throttles my concentrate output. The other side of the tee goes through a gate valve and back to procon pump inlet, this is my throttle valve to restrict recirc flow and also increase my pressure. When i get around 250 psi the procon pump pulsates a little then the motor stalls. I talked to bill and joe from midwest and atlantic, they both felt that more pressure would just foul up membrne faster but gave me procon's number. So i called procon to see if a 1hp motor would give me more pressure on the series 4 pump. first off i have a clamp style pump so i can only use a carbonator motor which is a max of 3/4 hp, but even if i had a bolt on style pump and put a bigger motor on it, the procon tech told me that their pumps are only rated for 250psi output, he said after that the veins are subject to damge. However i also asked about using it as a recirc pump with 300psi static pressure on each side and he said it would be fine. So i believe the 250 psi is above my feed pressure of 50-70psi therefore i would put a 1 hp motor on it if it was a bolt on style.

I also put a cheap 330gph water pump on it as a recirc pump with a flow meter. I had it recircing 5gpm with 200psi system pressure but water discharge did not change so i took it back off. If i went higher than 200 psi the recirc pump would stall.

So then i looked into multistage pumps from flotec at northern tool, dayton at grainger, goulds, and meyers. A 3/4 or 1 hp 16 stage will deliver 170psi @ 4-5gpm and range from $400-$600 so now if i went this route i would need to feed this pump with my procon pump to add pressures. Then i found an all aluminum hydraulic pump for $100 its item #1034 at northerntool.com It is rated for 8 gpm @ 3000rpm and has a max psi rating of 3650. It has a 5/8 keyed shaft so i bought one and found a used 1hp motor to direct couple to it. hoping it will have at least 5gpm flow with 300-350psi

I have been timing my water discharge and get about 50gph and about 10gph of 6% concentrate so i guess its running as a 60gph ro and i have about $900 invested we let it run all day and night and it hardly fouls we rinse once a day with about 200 gallons of water. I enjoy the experimentation but want to achieve more thoughput with higher pressure to make it more practical, since we have 1700 on vac this ro won't nearly cut it. If i could get around 100gph then adding another vessel would make it keep up with the evap which is about 180gph.

Does anyone know how many gph a manufactured 4" x 40" ro would process.

Also any ideas on increasing effeciency of the membrane is welcome

Thanks for all the posts guys

[arcticmaple8]

Markct - my membrane xle4040 was $225, 300psi ss vessel 4040 $128, procon pump series 4 brass $120, 3/4hp marathon motor $134, this stuff is all from atlantic ro. www.midwestro.com check out the filmtec pricesheet

i had a sprinkler booster pump already to use but orignally planned on a northern tool utility water pump 1/2 hp 720gph for a feed pump $50, pressure gauges 300psi liquid filled off of ebay $30 each, and the rest is plumbing supplies approx $100 thats roughly $800 but there is always more misc...

[markct]

even adding a larger pump and a second membrane sounds very workable for a reasonable cost, i think that sounds like the route i will start heading for next season.

[500592]

Does anybody have a parts list for a single membrane ro and a link to get it al I am new to this ro stuff but it is something I am interested in thanks