Depends upon the dialysate flow rate, and RO usage.
Dialysate flow rates can range widely, but usually only up to 800, 400 is the lowest I have seen most machines use. Also, depends upon the proportioning system. But a basic way of looking at it is this in a worst case scenario. An 800 flow rate would use .8 liters a minute. .8 x 60 = 48 liters an hour. 48 lph x 4 = 192 liters per treatment or about 49.5 gallons of water. ROs (reverse osmosis) for home can have a 50 - 75% recovery rate, meaning at 50%, every gallon of water made, took 2 gallons to make. So if the RO is at its worst… 50% recover, we take 192 (49.5) x 2 = 384 liters (99.1gallons) of water per treatment.
I know this is a long winded explanation, and it is the worst case of all involved.
My Freni uses around 600 litres for a 4 hour session, 500 dialysate flow rate and around 900+ litres for an 8 hour session, 300 dialysate flow rate. As Australia seems to always be in the grip of a drought I feel quite gulity about the amount of water I use, seems like the perfect reason to bring a machine like Nxstage down under.
If you use an R/O it pays to pipe the waste water from the R/O (but not from the dialysis machine) outside and use it for watering the garden, topping off a pool, etc. where it substitutes for fresh water you otherwise would use and hence is not wasted. It’s not hard to do as it is very low pressure.
Hmm that’s a thought, although not sure what the authorities would think about it.
I will certainly be bringing up the ‘aqua ethics’ & bonuses of having water saving dialysis machines when I attend the NKF conference later this year (the NKF conference UK, not to be confused, with similar in the USA). Fresenius have gone down a further notch with me. 600 litres! My god!
When we were on the Fresenius using a RO water system we were using quite a lot of water… Looked at past water bills it was between 450 and 475 gals per treatment (we were running nocturnal 7 hrs/6 days/wk TX’s)…
Like Mel suggested you can use the waste water from the RO to water your yard… I had mines drain into a tub and within the tub installed a sump pump that was used to pump water to my potted plants thru a drip irrigation system that I set up… Works great except during the winter months my back yard was a SWAMP… had a mosquito problem in the spring…
We tried to use a DI water system which uses a lot less water but had problems with LAL (Limus Amoebocyte Lysate) being too High… the endotoxin were too High… So we switched to a RO water system… This was when we first started Nightly Nocturnal Hemo Dialysis about 7 years ago…
The cost of the extra water is well worth it… You won’t regret it…See if you can get some kind of discount of MEDICAL use of the water…