ro waste water ( not a typical question)

G

goda

In Memoriam
ok at work we have two 75 gallonperday membrains in paralell. they dont seem to make 75g aday but its waste water is 1 gallon every 3 minutes... does that sound about right?

or are we better off getinng a new ro unit
 
its onthe way :P

but i will tell you even after DI there is traces of phosphate. and really high ph

we are tryign to decide weather to order new membrains or a whole new unit and get a good one
 
if you look on ebay you can get membranes for fairly cheap...

but if you think the whole RO unit is muffed up then a new unit is probably the best bet
 
lol thats what the old owner of the store would do...

the old owner had the thing compleatly diy'ed
the wrong flow restrictiors. pipes everywhere. no flush kit ( and this unit runs non stopped)

already talked hte new owners into paying a lil more for somthing that we know will work ( filmtec) and are now talkinga bout replacing everything( ro unit. wholestore carbon fitler. and water softener)
 
75g a day is about 3 gallons per hour. An average unit wastes 4 gallons to every one gallon made. If you were at a 4:1 ratio, you be making 1 gallon every 12 minutes or about 5 gallons per hour based on your waste being 1 gallon per 3 minutes. Doesn't sound like you think you are making 5 gallons per hour-especially since it is only a 75gal membrane. I would get a new system as this one is inefficient.
 
i think one problom may lie in the fact that teh two membrains are paralel instead of one being fed by the other ones waste.
while doing htis would increass tds and lower gpd slightly . it would save water
 
The second one won't work if it's feed from the first filters waste water, the pressure won't be enough. I would ditch the second membrane if it were me.
 
is it normal for the psi to go upto 90 ?

we are using two membrains one restrictior ( 90 gpd restrictor)should we be using the 180 gpd?)
anyways we are bypassing a membrain slightly to decrease the pressure to 80
 
90 won't hurt anything, membranes are tested to over 200 psi. If anything a housing or plumbing would fail before the membrane but 90 is not bad, it willl make water faster.
 
If you have two 90 gpd membranes in parallel you should have two 90x4 gpd restrictors, with a 4:1 waste:permeate for each membrane.

Russ @ BFS
 
whats a 90x4 according to spectrapures diagram you only put a restrictor after the second membrain

and they are in series btw
 
and if in series should it be one 90 gpd flow restrictor ( it is two 90 gpd)



anyways just tested the water

water from tap is 300 ppm tds water after carbon is 260 water after ro is 240 replacment will be coming soon lol

now my personal ro unit test at 12 tds ppm after membrain.. dosnt seem to bad considering it is a year old GE system with the carbon never changed..
 
and if in series should it be one 90 gpd flow restrictor ( it is two 90 gpd)



anyways just tested the water

water from tap is 300 ppm tds water after carbon is 260 water after ro is 240 replacment will be coming soon lol

now my personal ro unit test at 12 tds ppm after membrain.. dosnt seem to bad considering it is a year old GE system with the carbon never changed..
 
You want a flow restrictor sized to allow the flow of 3 to 4 times the permeate flow. So you have 2 x 90 = 180 gpd permeate, and you'd want 4x180 = 720 gpd flow restrictor.

When you get up to double membrane systems I like the adjustable flow restrictors even more...

Russ @ BFS
 
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