R/O waste water question

[Scotty Buttons]

Where I live water is really expensive. I'm just curious if there is any way to reduce the amount of waste water produced from my R/O system? I just got a 75gpd R/O D/I unit from BRS and it seems to make alot of waste water. Thanks in advance

 

[Crabs McJones]

Where I live water is really expensive. I'm just curious if there is any way to reduce the amount of waste water produced from my R/O system? I just got a 75gpd R/O D/I unit from BRS and it seems to make alot of waste water. Thanks in advance

You could do the 150gpd upgrade. It essentially takes the waste water from your ro unit and filters it though a second ro membrane to filter it down more. So you produce double the water with half the waste

 

[mfinn]

Spectrapure has a membrane that has a 2:1 ratio ( waste to product water).

 

[mfinn]

You could do the 150gpd upgrade. It essentially takes the waste water from your ro unit and filters it though a second ro membrane to filter it down more. So you produce double the water with half the waste

Correct me if I'm wrong, but don't you go through di resin at a faster rate because the tds going into the second membrane has a much higher tds, resulting in higher tds coming out of it?

 

[Crabs McJones]

Correct me if I'm wrong, but don't you go through di resin at a faster rate because the tds going into the second membrane has a much higher tds, resulting in higher tds coming out of it?

You do experience an increase in TDs, but I personally haven't noticed to much of an increase in DI consumption. Dont get me wrong, my di consumption has increased. But not by as much as I was anticipating.

 

[mfinn]

You do experience an increase in TDs, but I personally haven't noticed to much of an increase in DI consumption. Dont get me wrong, my di consumption has increased. But not by as much as I was anticipating.

I figure there has to be a trade off. Otherwise we would all be doing double membranes?

 

[Bayareareefer18]

Also what is your water pressure? I agree with the 150gpd upgrade. My water pressure wasn't sufficient so I added a booster pump which increased production and reduced waste.

Also can find a use for your waste water....

 

[Bayareareefer18]

With my BRS 150gpd tds going into DI is like 2 or 3. I notice it's much better with booster pump supplying 82 psi at the membrane

 

[chipmunkofdoom2]

Where I live water is really expensive. I'm just curious if there is any way to reduce the amount of waste water produced from my R/O system? I just got a 75gpd R/O D/I unit from BRS and it seems to make alot of waste water. Thanks in advance

How much exactly are you paying for water? According to CSU's website, people in CS pay $81 for 1,336 cubic feet (10,000 gallons), which works out to be about $0.0081 per gallon. At those prices, with a 4 to 1 waste to product ratio, each gallon of RO/DI water costs about $0.04. At those prices, 100 gallons of deionized water costs you $4.

The way a reverse osmosis membrane works is by forcing water through a membrane under pressure. The small pores in the membrane allow water molecules through, but not the larger solid particles. The waste water that flows down the drain washes those particles off the membrane. If you don't have an adequate waste to product water ratio, then your membrane will fail prematurely as the solids build up and clog the pores. The reverse osmosis systems that we use in the hobby must make waste water. There's unfortunately no way around that. Not without buying a much more sophisticated and expensive industrial treatment solution.

 

[Scotty Buttons]

You guys are great, thanks for all the advice. I think I will look into that spectra pure membrane.

 

[Scotty Buttons]

I do collect the waste water and plan on using it to water my lawn... when I actually get some grass lol

 

[paphater]

I do collect the waste water and plan on using it to water my lawn... when I actually get some grass lol

That's what I do. Bought 30' of RO tubing and just run it out the dog door to the yard.

 

[JoshH]

I figure there has to be a trade off. Otherwise we would all be doing double membranes?

It really depends on your source waters TDS. If it's over 350 or so it's not worth running a second membrane as the increased TDS coming out of the dual RO consumes far more DI than it's worth. I run a spectrapure 90GPD with a 75 GPD Upgrade kit and am around 2:1 waste to product ratio. Incoming TDS 241, after dual DI 0-1 TDS. So no excessive DI consumption for me and low waste, best of both worlds and @Scott Jeffries I second @mfinn with spectrapure, absolutely love mine. And just so you know, your current 75 membrane should be at a 4:1 ratio which is why it seems like your wasting a lot of water.

 

[Ferrell]

In the process of setting up a waste water barrel for my wife to water flowers. Fill all her jugs at night when I make water. Also use water for dogs, cats and chickens. Could probably find other uses if I really thought about it

 

[MushFarmer]

If you harvested rain water in barrels and could heat that water up via direct sunlight or something else, I believe the RO membrane rejection rate would increase a few percentage points.

 

[Jesterrace]

In the process of setting up a waste water barrel for my wife to water flowers. Fill all her jugs at night when I make water. Also use water for dogs, cats and chickens. Could probably find other uses if I really thought about it

I have an LFS that uses their waste water for their freshwater tanks. Perfect balance since there are still some minerals/solids there (which freshwater tanks need) without the ridiculously high TDS. Just an option for those who might have both salty and fresh tanks.

 

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[Scotty Buttons]

Slightly off topic, but what is the longest amount of time i can store mixed saltwater? I bought a couple of new polyethylene containers one for R/O and one for salt, just not sure how long I can keep saltwater in there.

 

[MrChris]

Where is your unit set up? Mine is in the basement right next to the washer. I put my waste water tube in my washer and use it to do laundry while I'm making water. Helps ease my mind. [emoji41]

 

[Scotty Buttons]

Mine is in my basement. I drilled a hole and ran my waste water to my backyard where I'm currently collecting it in a 225 gallon tote