Ro/di system questions

[Kitesurfjesus]

Ok so I was looking at different RO/DI systems being that I pay for water in the city I live in and don't want to waste a bunch of water so I was thinking of going with a 1-1 ratio system. My question is if I instead of dumping the waste water back down the drain (I also have a sewage charge on my utilities bill) how many times can already filtered water be filtered? As in if I only need 50g a month for water changes I will essentially be paying for 100g if I were to save that waste water and build a pump to run it back to through the filter to utilize as top off water?

 

[Kitesurfjesus]

Or are there any systems out there that have no waste water output

 

[nelix10]

You could use that water for toilets , but to recycle it back through the rodi would ruin filters quickly! If your waste water from the rodi had 200ppm tds and added it to regular tap water over and over you would have very polluted water going into your filter unit!

 

[Phranque]

All RODI systems have waste water.... it the nature of how the reverse osmosis membrane operates. The incoming water pressure is used to both push water through the membrane and flush away the waste left over from the water that has made it through. With a dual-membrane system, like the BRS 150gpd, "waste" water from the first membrane is pushed into the second one, then out to the drain, so your wasted water is cut in half for the production.
I use my waste water to do laundry.....