RO/DI System

[AFU]

Since y'all are posting pictures of your RO systems, here's mine at work. 20,000 gallons per day of 800 k-ohm-cm permeate, 5 and 7 HP pumps, 30 Filmtec BW30-4040 membranes, 80% recovery ratio, net driving pressure of 160 psi in the first pass and 210 psi in the second pass.

Yeah, I know, I'm evil. Just couldn't resist.

WOW. that is the real deal. I want one. haha.

 

[PurdueWaterGuy]

WOW. that is the real deal. I want one. haha.

Running the 460 VAC 3-phase for the pumps into your house might be a bit of a problem ;-)

 

[Buckeye Hydro]

Check the pressure ratings on all the components, plan for the worst, hope for the best.

Plato - Can't say for certain as that's not one of our systems, but guess what the weak link in the chain typically is concerning abilty to withstand high pressure on a system like yours. You have to consider the tubing, fittings, prefilter housings, RO membrane, membrane housing...

It's the clear housings. If you have any chips, scratches, etc, in those housings, their ability to handle pressure is even lower.

Russ

 

[PurdueWaterGuy]

All this talk of failing filter cannisters conjured up a flashback - once upon a time I came into work to find my ion implanter (sort of a giant mass spectrometer mated to a particle accelerator) shut down. The 20" tall DI cannister had gotten dirty and was restriciting flow, and the positive displacement pump (made by Procon, like the one in your picture) kept on pushing, until it split the cannister in two, leaving a ring with the top threaded part attached to the machine, and bounching the bottom half and IX cartridge across the lab.

Ahh, the bad old days....

 

[Plato]

hot damn lol is that a 3/4 hp motor???? that thing is a monster.
i meant over 90 for the 8800 motor, but for yours i don't know 120 psi man u must have good water production? what is your ratio with that dual membrane?

I thank its only a 1/4 hp motor with a 50 or 60 gpd pump head. The pump is in my apartment garage. It is gravity fed by a vat, so all pressure is supplied by pump. My product rate, well I fill a two hundred gallon vat that when toped off holds 220 gallons. I turn the pump on and the waste on the ro is 1 to 4 but the waste water goes back into the 200 gallon vat. My water that I fill the vat with starts at 50 ppm and after the ro its 0. By the end of the 200 gallons it goes up to 300 ppm and the ro goes up to 2 or 3. Its all controlled by float valves to shut the pump off if the feed vat goes empty or the product vat gets full. So out of 220 gallons I get 200 gallons if ro/di water to 20 gallons waste. At the start of every 200 gallon cycle I flush the membranes for 5 minutes and after I run ro/di water through the membranes for 5 minutes to prevent scaling and buildup.

 

[Plato]

Yeow. I know you haven't had problems yet, but...

120 psi on the clear housings is something to avoid. If you can move the pump inlet/output to after the prefilter housings that would be a good idea.

Russ

Yes, I'm aware that 120 can bust the housings. I'm adding a third membrane to fix that.

 

[Plato]

+1 on moving the pump to after the clear polycarbonate filter cannister. Not pretty when they fail. Been there, seen that, had to clean up after others. :-(

Noticed that your pump doesn not have the built-in pressure relief valve, watch your pressures.

Check the pressure ratings on all the components, plan for the worst, hope for the best.

No, but it does have a pressure valve that any thing over 130 gets bypassed back to the holding tank. The pic is from when I was testing the system not its final installation. Its electronicly controlled with a few safty features built in. Run dry protedtion, water leak protection, over pressure or under pressure protections. And if everything fails it in my garage so it will just leak out the door, it sets in a sealed pan.

 

[fishsticks4sale]

Yes, I'm aware that 120 can bust the housings. I'm adding a third membrane to fix that.

3membranes? will that improve your ratio?? 1:1 maybe even .5:1

.5 = wastewater
1 = goodwater

 

[Buckeye Hydro]

Plumbed in parallel, I assume....

 

[Plato]

Plumbed in parallel, I assume....

Yes, with individual flow restrictors per membrane.

 

[Plato]

3membranes? will that improve your ratio?? 1:1 maybe even .5:1

.5 = wastewater
1 = goodwater

The third membrane will reduce overall pressure at the membranes. I'm gussing it will be around 90 psi for three. As far as ratio I still set the waste to product at 4:1. But my waste is dumped back to the supply vat. On 220 gallons of tap water I filter out 200 gallons of good ro/di water and dump the remaning 20.

So that woud be a 10:1 ratio

10 = good
1 = bad

 

[fishsticks4sale]

what the heck for every 10 good gallons u only get 1 bad????
for better performance is it best to have....for example one membrane rated for 75gpd with a restrictor, and then add another membrane with its own 75gpd restrictor? so each membrane now will have its own. mine i currently have 1 restrictor doing the job on two membranes rated 75gpd each, total 150.

 

[PurdueWaterGuy]

90% rate of recovery - how long do your membranes last? Even with with two water softeners operating in series to get all of the scale forming minerals out of the water, there's enough silica in our water that I can't go above 80-85% recovery without fouling the membranes. They make chemical cleaners to remove calcium and biofilms, but once you deposit glass on a membrane it's pretty much a lost cause.

The third membrane will reduce overall pressure at the membranes. I'm gussing it will be around 90 psi for three. As far as ratio I still set the waste to product at 4:1. But my waste is dumped back to the supply vat. On 220 gallons of tap water I filter out 200 gallons of good ro/di water and dump the remaning 20.

So that woud be a 10:1 ratio

10 = good
1 = bad