RO Concentrate TDS Still At Drinkable Levels.....

[ptrick21186]

Ok so I have two 3 channel TDS meters on my 7 stage RO/DI unit....

1. Water coming into unit
2. Water after sediment and carbon filters
3. Water after RO membranes
4. Concentrate out of 1st membrane (feeding 2nd membrane)
5. Concentrate out of 2nd membrane
6. Water after DI resin.

So my TDS coming in is about 210 and the concentrate coming from the membranes is about 280. I've read that anything lower than 300 is still "good" water. Soooooooo......that being said I'm wondering if I can't reuse this water for....well anything. What is everyone's thoughts? Find a way to save and reuse this water or let it go down the drain? I'm thinking about getting some 55gal blue drums from work and filling them for garden water. But what else?

 

[ptrick21186]

Zombie Apocalypse storage?

 

[Buckeye Hydro Verified Sponsor]

With your current configuration re your meter probes, you don't know the TDS of the permeate from either membrane. You want to know that so you know when to change your membranes.

Russ

 

[Buckeye Hydro Verified Sponsor]

Yes - your concentrate has a lower TDS than the tap water of many.

 

[ptrick21186]

With your current configuration re your meter probes, you don't know the TDS of the permeate from either membrane. You want to know that so you know when to change your membranes.

Russ

#3 is the permeate after the membranes

 

[Buckeye Hydro Verified Sponsor]

#3 is the permeate after the membranes

because the second membrane will fail before the first membrane, you may want to have an independent probe after each membrane.

Why do you want to know the TDS of the concentrate after the second membrane?

 

[ptrick21186]

because the second membrane will fail before the first membrane, you may want to have an independent probe after each membrane.

Both of the permeate lines from the membranes come together before going into the DI resin. I figure I would just replace them both when I start seeing elevated levels. I see what you're saying though. It'd be better to see them independently so you could know specifically which one to replace. Yes the second membrane is going to plug up before the first seeing as how it gets higher TDS but my theory is is the other one probably isn't far behind so just replace them both at that point.

 

[ptrick21186]

Why do you want to know the TDS of the concentrate after the second membrane?

For the purpose of seeing the TDS level of the water if I planned on doing anything with it like I was saying in the original post. If its too high of TDS I'd just let it go to the drain, but seeing as how it's usable I'd like to make some use of it.

 

[jda]

Many have saved the water for use in the yard. Also good for African Cichlid tanks.

 

[KrisReef]

For the purpose of seeing the TDS level of the water if I planned on doing anything with it like I was saying in the original post. If its too high of TDS I'd just let it go to the drain, but seeing as how it's usable I'd like to make some use of it.

Yup, mine waters my apercot tree. It just floods the ground just uphill from the tree and it doesn't just go to the sewage treatment plan to dilute their collection.

 

[jda]

If you live in a warm climate, you can use the mini line right out into a raised bed or landscaping with some Ts and stuff to split up the output. Of course, if this freezes it shuts down the whole thing.