Re-filtering reverse osmosis waste water?

Helmut79

Helmut79

Well-Known Member
I have a question regarding RO filters to people who knows how reverse osmosis filter systems work.

RO filter makes pure water and waste water. Mine is about 1 to 3 in favor of waste water. What if I re-filter the waste water to save water this way?

Do you see a reason why it's a bad idea?

Does it do anything bad to the RO system?

I've tried once and I got the waste water purified without a problem.

Where's the catch? Please, someone explain.
 
Okay, for some reason I can't find anything about this. Simply nothing.

But how do I know if the filter (I guess we're talking about the main membrane) is starting to wear out?

What are the first signs?

How much more quickly could it wear out this way?
 
I will test it and post back results.

I'll measure ppm going in / coming out of RO (both purified and waste).

Then I'll refilter waste water and take measurements again to see the difference.

I will also measure pure water to waster water ratio to see if it will change.
 
Helmut79 said:
I will test it and post back results.

I'll measure ppm going in / coming out of RO (both purified and waste).

Then I'll refilter waste water and take measurements again to see the difference.

I will also measure pure water to waster water ratio to see if it will change.
Click to expand...

Purp had it. Your membrane wares out faster!
Did you know you can get a restrictor for that unit that will give you a 1 to 1 ratio? Ask for it at your dealer or place of purchase/internet......Again your membrane will ware out faster.

I pay only $30 a pop for them......Get 4 and it's free shipping..

https://www.filtersfast.com/P-Appli...2&fsrc=G1F5F&gclid=CPqCz4OFntACFfIK0wod-IEAnw

This fits all the RO units sold for growing and most home units too (GE, etc).

Take the sticker off the membrane with sterile hands or sterile tools! Works better, faster...longer..
 
Oh, yeah...the waste gets cycled to our chickens and other livestock. Then overflows to the duck pond.....
 
Helmut79 said:
I have a question regarding RO filters to people who knows how reverse osmosis filter systems work.

RO filter makes pure water and waste water. Mine is about 1 to 3 in favor of waste water. What if I re-filter the waste water to save water this way?

Do you see a reason why it's a bad idea?

Does it do anything bad to the RO system?

I've tried once and I got the waste water purified without a problem.

Where's the catch? Please, someone explain.
Click to expand...

There's no problem with doing that at all other than one thing: The plumbing it takes to do it cost far more than the water does.

What you would have to do is capture the waste water, then run it back through the RO filter under pressure. That, in and of itself, requires two different systems.

You can't simply plumb the waste line back into the intake line because you'd get a pressure build up on the waste line that would bring all filtration to a screeching halt.

The only way to really do it would be to have a large reservoir to capture the waste water in, then incorporate a high pressure pump and plumbing to pump it back through the filter again after the main water source was shut off.

Most RO units require at least 45 psi. The pump required to do that is going to cost you around 600 dollars.

The water is far, far cheaper than that.

If conservation is your goal, however, you can always capture waste water for general watering of plants. There's nothing at all wrong with it. Waste water is actually an oxymoron in the case of RO as it's just the water that couldn't make it through the membrane due to volume and back pressure.

Think of it this way: You turn on your kitchen faucet and start to fill a glass with water. The glass gets full. The water then starts running over the edge of the glass. That's waste water in RO. Same thing.
 
TacoMac said:
There's no problem with doing that at all other than one thing: The plumbing it takes to do it cost far more than the water does.

What you would have to do is capture the waste water, then run it back through the RO filter under pressure. That, in and of itself, requires two different systems.

You can't simply plumb the waste line back into the intake line because you'd get a pressure build up on the waste line that would bring all filtration to a screeching halt.

The only way to really do it would be to have a large reservoir to capture the waste water in, then incorporate a high pressure pump and plumbing to pump it back through the filter again after the main water source was shut off.

Most RO units require at least 45 psi. The pump required to do that is going to cost you around 600 dollars.

The water is far, far cheaper than that.

If conservation is your goal, however, you can always capture waste water for general watering of plants. There's nothing at all wrong with it. Waste water is actually an oxymoron in the case of RO as it's just the water that couldn't make it through the membrane due to volume and back pressure.

Think of it this way: You turn on your kitchen faucet and start to fill a glass with water. The glass gets full. The water then starts running over the edge of the glass. That's waste water in RO. Same thing.
Click to expand...
So if I limit the flow to the filter will it produce less waste water as a percentage of total water used? a
 
TacoMac said:
There's no problem with doing that at all other than one thing: The plumbing it takes to do it cost far more than the water does.

What you would have to do is capture the waste water, then run it back through the RO filter under pressure. That, in and of itself, requires two different systems.

You can't simply plumb the waste line back into the intake line because you'd get a pressure build up on the waste line that would bring all filtration to a screeching halt.

The only way to really do it would be to have a large reservoir to capture the waste water in, then incorporate a high pressure pump and plumbing to pump it back through the filter again after the main water source was shut off.

Most RO units require at least 45 psi. The pump required to do that is going to cost you around 600 dollars.

The water is far, far cheaper than that.

If conservation is your goal, however, you can always capture waste water for general watering of plants. There's nothing at all wrong with it. Waste water is actually an oxymoron in the case of RO as it's just the water that couldn't make it through the membrane due to volume and back pressure.

Think of it this way: You turn on your kitchen faucet and start to fill a glass with water. The glass gets full. The water then starts running over the edge of the glass. That's waste water in RO. Same thing.
Click to expand...


600 dollars for the pump is definitely overkill. Not sure which kind of RO filters are you talking about, but my pump (automated) cost 100 bucks new from the store and it makes my RO filter give me 1 to 3 pure water. Works well.

I have a 4 ton reservoir to capture all that RO waste water.

Everything is exactly as you said except the cost of the pump.

The main thing is that I don't want to kill the frogs in the pond who are having their "winter vacation" under the ice, but the pond is my only water source and my RO filter is making 1.5 ton of pure water every week. Thats about 4.5 ton of waste water every week. In total of 6 ton of water pumped out of the pond every week, so I'm guesstimating the pond is about 150 tonnes big and I'm just thinking that if the membrane will ware out faster and I'd have to buy a new one, I would still benefit from it by not pumping the pond dry so fast.

All those filters and pumps and plumbing together multiplied by many times are cheaper than any other kind of alternative for me. The pond is my only water source.

I should show you pictures how my system is built. It can be all built quite cheaply to be honest.
 
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