....And if you can't read French, you can always cut and paste it into Google translator to convert it to English.
Here's my home made system:
I supply it with very hard, cold, raw well water, which goes through a tiny R.O. booster pump to increase pressure and then down the line to three 75 gallon per day membranes. I stopped using the prefilters years ago. They do nothing now. The raw well water goes through the booster pump and straight to the membranes. This unit runs 24/7 and provides all the water I need except in the summer when it's very hot. At that time of year however, I can draw water from a nearby stream. The membranes never make the full 75 gallons per day; but, I do get about 150 gallons per day in total from all 3.
My system works on a 1:1 ratio of product water to waste water. I accomplish this by kinking the waste water lines just enough to restrict the outflow so that it matches the outflow volume on the product water lines. It's a very crude design; but, very effective.
The booster pump needs to be replaced about once a year, as the raw well water is so hard, they usually just quit after about 12 months use. So, that's a cost of about $150.00 per year. Plus, the membranes last about a year as well. They're $45 each. So, for aproximately, $300.00 a year, I can make all the R.O. water I need for my greenhouse needs.
My greenhouse is 1440 square feet (30' x 48') and it's full! I have 6 benches running the length from the front to the back wall. I thoroughly water one bench each day and mist/spot water the rest of the greenhouse each day. I do not water on very dull days; so, on those days, I get to build up a bit more water in storage. I have a 6,000 gallon cistern underground, next to the greenhouse for storage.
From about September through to the end of April, I have plenty of R.O. available for my needs. Starting in May, I hook up the outdoor water line and begin drawing water from the stream, which I use for watering, not misting. I water the benches in rotation. So, in the summer, when there is lots of light, each bench will be watered on a 6 day cycle. During the summer, I use the stream water to water one bench. Then, I turn a couple valves and switch to using R.O. water from the cistern and I do the spot watering and mist the whole greenhouse with R.O. water, including the bench that was just watered with the stream water. This way, I can use all the water I want without any concern for wasting it or running low, while I'm flooding the pots with the stream water. Then, I thoroughly mist that bench as well as the rest of the greenhouse with the R.O. water. I mist the bench that I just watered with the stream water so that the R.O. can wash off any of the residue that the stream water left behind....so, I have nice, clean, shiny foliage without water marks when it all dries.
EDIT: Notice the waste water lines and the product water lines coming out of the bottom of the membrane housings. The lines were originally from the same roll of plastic tubing. However, over time, the waste water lines have turned dirty grey/black because they are carrying the super high TDS waste water away. The product water lines, which carry the cleaned, purified water, are still clean. This system is about 6 years old now.
ermeate ratio, as opposed to the standard 4:1, so we'll see about the membrane life. I have a well (and no chlorination), so use 20µ/5µ/carbon prefilters. The dual sediment filter setup is new - my current one has a single 5µ sediment filter, but we have a local problem with "iron bacteria" clogging the finer one too fast.
