The basics of building a small RO

[barnbc76]

So I've been looking into RO's the past couple of years but I didn't have the money then, still dont really but I realise I could buy myself some time and thus maybe put in some extra overtime and such to make up for it.

I really could use some help in this process as I am a bit too dense to understand everything needed. Sure I've spent hrs looking through these posts but I never find quite what I'm looking for.

I'm looking for something that could potentially do 50 taps. Currently I will probably only do about 25-30. Something that gives me the opportunity to expand. I usually boil when I get about 40-60gal on my 2x3 which gets about 8gph.

So I've read alot about the aquatec 8800 here and many seem to think this is good, for about $100 that seems alright. But then I get lost on the membranes combo. What membranes work and will do what i need it to. I see a housing/membrane combo for $63 for a 400 Gpd but will that even work with this pump? Also I saw combo 150 for about $33. Also I see many have a second pump, something 1/2hp or bigger is this a requirement or just a bonus addon to achieve higher % concentrate? I am looking to do this more or less as cheap as possible. Going from 2% to 4% would be great, but if this system has the capability to do higher next year or whenever by adding things that would be nice.

Given some of these examples of membrane combos what might I be able to expect for the flow? And what are my greatest areas for oppirtunity?

Thanks guys for the help.

[Cjadamec]

There are two rather distinct versions of R0 set ups. The small hobby version run off of the aquatec style pumps. Then there is the Pro version that runs off of high pressure larger horsepower bigger pumps. Pro versions process a lot of sap but use a lot of power and cost a lot to do so.

The hobby style which you want is plenty for your size of operation. You basically need the RO bucket. The guy making the RO bucket puts together a nice kit and its really not too much more money than it would cost you to buy all the parts and assemble them.

For a basic set up you need the pump, 2-3 membraine housings (the residential 10" ones), membraines for your housings get the 400 gallon per day membraines, tubing to connect all the bits, at least one needle valve, and pressure gauges.

I've been debating the whole RO bit myself but have yet to pull the trigger. I really need a better pan first.

[barnbc76]

I have seen the ro buckets, they look nice but I still would like to see the costs for doing it myself and understand it better.

[Cjadamec]

I have seen the ro buckets, they look nice but I still would like to see the costs for doing it myself and understand it better.

Amazon has everything you need to build a hobby RO. I've priced out building on a number of times and it seems I always end up in the 4-500 dollar range by the time I'm all done. I could probably get it down to 300 if I cut capacity down but I've got twice as many taps as you do.

If you look at the RO bucket website there is basically a parts breakdown of the parts you need to get an RO going. There's not too many parts you need to put one together.

[eustis22]

I usd hodorskibs plans and am very happy with the $300 I spent for my 4 150 gpd membrane set up.

[barnbc76]

So how do I know how many membranes I can use with this aquatec 8800 pump. It does not say, it says it works for up to 300gpd but nothing about how many at a time.... As my original thread title says I'm trying to understand the basics of building an RO, while emulating what someone else is doing is fine, I would have too understand it to properly select the comoonents.

[hodorskib]

Here is a link to my new website that has the information you are looking for: https://sites.google.com/view/mattatuckmadnessmaplesyrup/home
Although I have no affiliation with the RO bucket I have only heard very good things so if you are looking for a system ready to go that would be a very good option. If you want to do it yourself you can currently put together a 4 membrane system with 150gpd membranes for around 300 with all the parts. This will allow you to handle 50 taps without an issue. As for how many membranes you can run on the Aquatech pump I have found that it limits out at 3 x 400gpd membranes or 6 150gpd membranes. Hope this helps.

[barnbc76]

Thanks for the info that's the most comprehensive straight forward explanation I've found yet, with all the parts too. What would be the difference between running 2-400gpd vs 4-150gpd?

[hodorskib]

In theory the 2 x 400s should perform better but I did not notice a difference in running 6 x 150gpd membranes and 3 x 400gpd membranes. The 400gpd membrane housings started to leak at pressure above 120psi.

[jbutton]

So the aquatech 8800 can handle 6×150 Gpd housings or 3x400 gpd housing ? What is the rate per hour

[Cjadamec]

The largest aquatic 8800 series pump the, 88x2 models, can pump 2.34 liters per minute at 0 pressure and 1.51 liters per minute at 80 psi.

A 400gpd membrane can process ((400/24)/60)= .28 gallons per minute.

.28 gallons is 1.01 liters.

So by upping your pump psi to around 100 by controlling the needle valve on the outlet of your pump you will cut the pump flow to right around 1 liter per minute. 100 psi is around optimal for a residential grade filter and housing.

If you run 3 400gpd membranes in series you can maintain enough pressure and flow to run all 3 membranes.

Your flow rate per hour is governed by your pump. So in this case running around 100psi you will process .25 gallons per minute of raw sap per minute. Or roughly 15 gallons an hour.

Assuming you are starting with 2% sap, I believe 3 membranes in series will get you around a 6% concentrate. Out of that 15 gallons I think it brakes down to about 10 gallons of pure water and 5 gallons of concentrate. Those numbers might be a little bit off though.

[hodorskib]

You are just about spot on with your numbers from my experimenting over the past several years. I run my system at a little higher pressure usually around 125-135psi and depending on the temperature of the sap usually can remove about 6-8 gallons of water per hour.

[barnbc76]

Thanks again for the help, I think I'm on my way now, I'll be ording the parts soon. So I plan on using 2-400gpd membranes, what would the flow rate be for that in series or in parallel, could I get up to 6% with that system?

[Cjadamec]

All the flow rates I worked out were for the membranes in series. That's the most efficient way to get higher concentrate in the end product in a single pass.

If you are only getting 2 membranes you should run them in series. With 2 membranes I would think you should expect around 4% concentrate in a single pass. If you are starting at 2%.

An aquatech 8800 pump would have a hard time running 2 400GPD membranes in parallel at the operating pressures needed.

[barnbc76]

Thanks that's good to know.

[barnbc76]

Does it matter which size tubing you use whether 3/8" or 1/4"? Do you use the same size throughout the system?

[eustis22]

I use 3/8" from sap tank to pump, then 1/4" from the pump to the filter/membranes.

[DrTimPerkins]

All the flow rates I worked out were for the membranes in series. That's the most efficient way to get higher concentrate in the end product in a single pass.
If you are only getting 2 membranes you should run them in series. With 2 membranes I would think you should expect around 4% concentrate in a single pass. If you are starting at 2%.
An aquatech 8800 pump would have a hard time running 2 400GPD membranes in parallel at the operating pressures needed.

In general, if you plumb two membranes in series (the concentrate from the first is the input for the second), then you'll get higher concentration, but will have a lower through-put rate.

In plumbed in parallel (sap input into both membranes, concentrate from both membranes), you'll have higher flow-rates, but lower concentration.

What you want to do (higher concentration or higher flow-rates) will determine the pump(s) and plumbing configuration. Of course, you can always get real fancy and do something like 2 membranes in parallel feeding a third membrane arranged in series with the first two.

[rlapointe]

Does it matter which size tubing you use whether 3/8" or 1/4"? Do you use the same size throughout the system?

Typically, you want to feed the sediment filter with 3/8" and each membrane with 3/8" because the membranes have two outputs (permeate and concentrate). Take a look at the pictures below. The first is the basic home RO the second is a bit more elaborate w/ three membranes and a TDS meter to measure membrane efficiency.
19652
19653

[DRoseum]

I built a custom RO using an aquatec 8800 and 400 gpd membrane. Worked pretty well, seemed a bit slow at times, but it saved me a ton of boiling time and fuel! Planning to add a 2nd 400 gpd membrane for next season. Inlet was 3/8 and exits were 1/4. Ran around 100-105 psi.

https://youtu.be/s106bSrcfno
https://youtu.be/m_RBNFkq80U
https://www.sugartree.run/2019/03/end-of-season-equipment-cleaning.html
https://www.sugartree.run/p/sugaring-diy.html

[barnbc76]

Ok so that took me a bit longer to acquire all the parts, but in the end we got there. Me and my brother built ours from an aquatech 8800, with 2-400 GPD membranes it took a bunch of extra trips for stupid stuff but we finished tonight.

3% sugar content to 7% at about 105psi. Sap is pretty cold here and temps are below freezing, not ideal but it works. Only processed about 3.5 gal but can't wait to crank it tomorrow. Have about 50 gal to do. Will probably dial it to 6% for faster processing.

[BobMac]

New to the ro thing so bear with me,I was given a ss 4x21 membrane housing 300 psi rating.Would the 8800 pump work with this single
housing ? I see they are using 2 and 3 400 gpd membranes thinking this would be about the same ?Have 40 taps as of now could do another
10 to 15 but without a ro its not likely,what are your thoughts for a good set up with the 4x21 ? thanks in advance

[rlapointe]

Ok so that took me a bit longer to acquire all the parts, but in the end we got there. Me and my brother built ours from an aquatech 8800, with 2-400 GPD membranes it took a bunch of extra trips for stupid stuff but we finished tonight.

3% sugar content to 7% at about 105psi. Sap is pretty cold here and temps are below freezing, not ideal but it works. Only processed about 3.5 gal but can't wait to crank it tomorrow. Have about 50 gal to do. Will probably dial it to 6% for faster processing.

Hi barnbc76, just curious how long it took to process your 3.5 Gal at 105psi? And what kind of pump do you use?

[wobbletop]

Hi barnbc76, just curious how long it took to process your 3.5 Gal at 105psi? And what kind of pump do you use?

I'm not him, but he mentions the pump... aquatech 8800.

[barnbc76]

So I finished my last ro of the season, I didn't do as much as I usually do this year I was just too tired. I did approximately 220gal of sap. The processing rate fluctuated through the season. In the beginning of the season my sugar content was at about 3% and slowly fell to my last batch which was only 1.5%. When the sugar content was 3% or higher it took a long time to process. To remove the first 5 gal of water out of 50gal it would only take about an hr. But then it seemed like the rate was cut in half each hr. Until eventually it was no longer effective. The reason for this is because I did not have a tank for the concentrate so I just cycled it back into the sap tank. The weather also was often around 20 degrees at night so it made it more difficult in the beginning when trying to figure things out.
I initially tried using the plywood control panel but that proved to be too much work to move myself. Instead I used a tote and put the membranes housings inside a 5gal bucket inside which allowed me to cover it up sufficiently to keep it running in the cold weather outside. At the end of the season the RO really worked well as my sugar content was only 1.5, I think I removed close to 40 gal of water in the same amount of time it took to remove 20 gal during the colder temps. All in all I think I would recomend just buying the RO bucket for ease. But I'm enjoying today only having about 30 gal of sap to boil as opposed to the 70gal I started with..

[Ridge Creek]

New to the ro thing so bear with me,I was given a ss 4x21 membrane housing 300 psi rating.Would the 8800 pump work with this single
housing ? I see they are using 2 and 3 400 gpd membranes thinking this would be about the same ?Have 40 taps as of now could do another
10 to 15 but without a ro its not likely,what are your thoughts for a good set up with the 4x21 ? thanks in advance

Have you tried this yet? Curious how affective a 4” membrane is at lower pressure (125-150psi). Please post your results if you attempt this. Thanks