RO/DI question

abarrera

New member
How much waste water dose a RO/DI unit have per gal of pure water it produces. What is your opinion on the water saver model by the filter guy's

Antonio
 
so 4 gallons of waste for every 1 of purified? WOW that seems a bit extreme, has anyone tried to run the waste water from the membrane through another membrane like the water saver systems are set up to do?
 
yea i'm running my new 4 stage filter right now, and i got a 1/2gallon of pure water and almost 2 gallons of waste right now, so about 3-4 gallons per 1 pure gallon. this is a 50gpd model i'm sure with a pump, it would use less waste because it could run more water through the membrane
 
Standard units are 4:1 waste ratio. Every vendor around sells a dual membrane system feeding the waste into the second membrane, this is very common and has been done for years and years. Filter Guys is fairly new to the business and are promoting something as water saving but what the neglect to tell you is it also shortens the membrane life. Ask vendors like Spectrapure, Air Water & Ice, PurelyH2o and others who have been around for as long as 25 years and see what their long term testing has shown them. I would go with a vendor with more experience on the subject.
 
<a href=showthread.php?s=&postid=14019933#post14019933 target=_blank>Originally posted</a> by AZDesertRat
Standard units are 4:1 waste ratio. Every vendor around sells a dual membrane system feeding the waste into the second membrane, this is very common and has been done for years and years. Filter Guys is fairly new to the business and are promoting something as water saving but what the neglect to tell you is it also shortens the membrane life. Ask vendors like Spectrapure, Air Water & Ice, PurelyH2o and others who have been around for as long as 25 years and see what their long term testing has shown them. I would go with a vendor with more experience on the subject.
The Filter Guys are an Excellent vendor with tons of experience . Do you work for Spectrapure.?:confused:
 
I am glad that you have been around more than 2, 3 years I am also glad that you give good advice to people needing answers on RODI , but please don't downplay one of my favorite RC sponser,,,,,,,,Thankyou :)
 
I only downplay their questionable advice. Most all vendors and manufacturers tried water saving techniques years ago and found it is not effective long term so they choose not to sell something that they know is not worthy of their reputation. Membranes require constant flushing and the 4:1 waste ratio is how it is accomplished. Large companies like Spectrapure and other have testing labs where they can test their products for years before they introduce them to the public. They have units under observavation that have been running continously much longer than some vendors have been in business, thats why they are so successful. AWI has been around well over 25 years, Buckeye quite a long time. and Purely H2O can trace its roots back 10 or 15 years or more to Aquatic Reef Systems. All these vendors have dual membrane systems but none advertise them as water savers as they stand behind their products long term. Reducing the waste ratio will shorten the life of a membrane and it is proven time and again. As you vendor if they have a tes tlab capable of making test waters in excess of 250 TDS (their water in that location has extremely low TDS so is not representative of the rest of the Country) and how long have they had units in operation. I know others have units going for years and years non stop in waters exceeding 500 TDS or more so they get a true scientific test.
 
how much life dose it cut off the membrane? reason I'm asking is if it's only by 0-40% why not do it, if they can produce a 2:1 ratio it would still be less water wasted. Dose it effect both membranes or just the second one? if it only effects the second and has no adverse effect on first would make even more sense because you would only be needing to replace membrane 2 sooner than normal?
 
It all depends on the tap water quality. In some cases it cuts the life to months in others its not so drastic. You have to understand osmonic pressure and brine concentrations to know what I am talking about.
 
Not necessarily worried about the waste just curious as if this was worth spending money on or not? Thanks for your responses... looking into some of the other vendors now
 
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