[P @ F]

If you have , i have an RO question , am looking to get one and i have always wondered this .....
The rejected water , is it a higher TDS than the tap water going in ?

What i would like to know is .... Your tap TDS in and also the TDS of your waste.
Oh , and the RO you use .

This would be great  if you could spare the time

Cheers chaps  Rich   

[EZclean]

i use this one:

http://www.johnhewitt.com/ro.htm

was a bit cheaper when i bought it, £220ish i think.
i already was using a small DI vessel so got the one without the caninster.
had some teething problems but its been perfect since.

TDS in : 90-104
TDS out: 001
producing at about 70ltrs/hr

cant remember the waste but it was much higher than tap water, which sounds strange but true, i would take a reading but it goes down the washer outlet, and i'm not moving the washer. 

[Chris Cottrell]

My TDS in from the tap is 450 - 500 ppm and after the RO unit its around 3 - 4 ppm

The RO unit I have got is a RO Man 300gpd (3 x 100 gpd menbranes) pumped with a booster pump at 95psi

my waste ratio is 50/50

[P @ F]

Thanks for the replies so far , chris you didnt give the TDS of your waste , is it possible to get it , or have you burried yours aswell 

Rich

[Rob Smith]

Hi Chris,  my TDS from the tap is similar to yours.  How much water can you produce a hour?  Cheers,  Rob

[C.C.S.]

i think the tds of the refused water is around 900 ppm

[P @ F]

OK chaps , still not getting an idea here , CCS you told me the reject TDS but not tds of water going into the RO ,  :
come on peeps somebody give us a clue 

Rich P @ F

[tomy jackson]

thats cos the waste water is washing the ro ?

[Paul Coleman]

200 at tap.  29 after RO.  Waste 260.  Membranes are starting to age and a waste restrictor is fitted due to being on a meter with a merlin.
I thought that RO waste TDS would always be higher than tap TDS.  Surely that's the way they work - isn't it?

[d s windowcleaning]

tap 290
after ro 002   000 after di
waste from ro 345
im using a 200 gpd from ro man

[P @ F]

Now thats what im talking about , look at the last 2 post figures , good results , the waste is only 60 higher than the original product going in !
Now would it not make sense to save the waste and re use it , do this how you will , a booster pump is sure to be needed , but the waste i have heard is in some cases , depending on RO supplier can be massive in respect of the good water saved.
I for one will be delving a little deeper , not only for the money saving aspect , as im on a meter , but also for the green aspect , if we all looked at this then maybe hose pipe bans could be avoided.
I suppose what you also have to take into accont is the cost of filters and your tap TDS , for me i reckon its a win win situation , my tap is 140 so even if my waste is 200 its still gonna hit the RO second time round lower than a lot of your guys are getting it from the tap .

Any one POO POO before i blow money on an RO  ?

Rich 

[mikecam]

Now thats what im talking about , look at the last 2 post figures , good results , the waste is only 60 higher than the original product going in !
Now would it not make sense to save the waste and re use it , do this how you will , a booster pump is sure to be needed , but the waste i have heard is in some cases , depending on RO supplier can be massive in respect of the good water saved.
I for one will be delving a little deeper , not only for the money saving aspect , as im on a meter , but also for the green aspect , if we all looked at this then maybe hose pipe bans could be avoided.
I suppose what you also have to take into accont is the cost of filters and your tap TDS , for me i reckon its a win win situation , my tap is 140 so even if my waste is 200 its still gonna hit the RO second time round lower than a lot of your guys are getting it from the tap .

Any one POO POO before i blow money on an RO  ?

Rich 

Not sure why you would want to know the waste output TDS as its pretty irrelevant. It would also be useless for any comparison purposes without knowing the ratio of waste to product water anyway.
 I'm guessing you are looking to eliminate as much waste as you can? If so a twin RO would be the way to go. It wouldn't matter what RO system, them 300 GPD ones, merlins or 40/40s . If you assume a product to waste ratio of 50/50 then putting your waste through another RO will give you a 50/50 split again so your waste would end up as 25% instead of 50%, if you follow and i explained that right !!

[elite mike]

Now thats what im talking about , look at the last 2 post figures , good results , the waste is only 60 higher than the original product going in !
Now would it not make sense to save the waste and re use it , do this how you will , a booster pump is sure to be needed , but the waste i have heard is in some cases , depending on RO supplier can be massive in respect of the good water saved.
I for one will be delving a little deeper , not only for the money saving aspect , as im on a meter , but also for the green aspect , if we all looked at this then maybe hose pipe bans could be avoided.
I suppose what you also have to take into accont is the cost of filters and your tap TDS , for me i reckon its a win win situation , my tap is 140 so even if my waste is 200 its still gonna hit the RO second time round lower than a lot of your guys are getting it from the tap .

Any one POO POO before i blow money on an RO  ?

Rich 

Not sure why you would want to know the waste output TDS as its pretty irrelevant. It would also be useless for any comparison purposes without knowing the ratio of waste to product water anyway.
 I'm guessing you are looking to eliminate as much waste as you can? If so a twin RO would be the way to go. It wouldn't matter what RO system, them 300 GPD ones, merlins or 40/40s . If you assume a product to waste ratio of 50/50 then putting your waste through another RO will give you a 50/50 split again so your waste would end up as 25% instead of 50%, if you follow and i explained that right !!

great post, in other words get a cheap second ro , and pump the waste through

or if you have enough pressure just connect the waste to second ro

just change filters more often

win win when on a water meter

[formb]

In : 50

Out : 0

Waste : 120