Do all reverse osmosis filters burn tons of water?
I think I read this? Seems weird to me. Seems like the water should pass through, it does its thing, then water passes out ready to use. Do they all waste a ton of water?
No and I have been keeping an eye on this as well because I'm planing on purchasing one.
Some are downright horrible using 4 or 5 times the water IE 4 to 5 gallons for 1 gallon RO produced whereas some use a 1 to 1 ratio or 1 gallon of RO with 1 gallon waste water.
For every gallon that you use, you waste about 3-4 gallons.
Example -- if you use 3 gallons to cook you waste 12 gallons
As is, the normal is between 2:1 and 3:1 but you can tune them by putting a valve on the outlet. With the system running normal slowly close the waste valve while watching the good water outlet till the production starts to slow down, you will probably have to wait 30 seconds or so to let pressure equalize in the system before each movement of the outlet valve but with patience you should be able to get things down or close to 1:1.
You will not get full production but dramatically save waste. My waste goes into a 70 lt bucket with lid and a float valve same as the RO water and is used for other things so as not to waste any if possible.
My system produces between 1/2 and 2/3 its capacity but the discharge is greatly reduced, (I'm not usually in any rush) having float valves makes the system turn off when full to save on flooding desasters.
Having 2 x 70lt( about 20 gallons each) under the kitchen sink is obviously not possible but takes up little room in the fish den or utility room.
The reason I installed RO is because of ph fluctuations, from the well it comes out at about 30 - 38 TDS but ph about 5 - 5.5, after the system its 0 or 1 TDS and about 6.2 - 6.6 ph easy remineralized to what I want, even my waste/discharge is only in the 80 - 105 TDS and 5.5 ph, I can easily pump it back into our 2500lt holding tank or use it for my aquaponics.
RO systems are easy to configure to what you want, nowadays there are filters for everything.( mostly to make money for venders)
oops, I almost forgot, running 2 x membranes in series will also reduce waste/ discharge (3 does not work even better, its actually worse) In say a 50gpd system, You take the dischare/waste water from the first filter and pass it through the second filter so you are now getting 50 gpd from the first membrane and 50gpd from the second with the same amount of discharge as if using only 1 membrane, also doubling your daily production in gpd(gallons per day)