[mike1986]

Can someone please explain in simple terms why people use reverse osmosis for water purification?

Do you still need to use resin when using this method?

I have tried reading up on reverse osmosis and its just going straight over my head 

I know literally nothing about how this woks, as i have always just used resin and DI vessel.

Thanks

[8weekly]

Reverse Osmosis removes about 90% of impurities and therefore you will use much less resin and your water production will be cheaper. Do I win a prize? 

[bobplum]

if your TDS reading is lets say over 100 then you will probably be best using a R/O system to bring the TDS level down to a manageable level lets say 30 then use the DI resin to bring it down to 000

If you didnt use the R/O you would need tonnes of DI resin

If your TDS level is low lets say 50 then you could probably get away with using resin only

You can use just resin but it will cost in the long run

[Spruce]

An R/O membrane is like an air filter in your car or van engine's air intake.

The airfiter is made of a porous material that has tiny holes in it that allow air through but not dirt. So we have to change our airfilters regularly as they eventually get clogged up with the dirt they have trapped.

An R/O membrane does the same as it stops the impurities in the water passing through it like calcium and magnesium. So water molecules can pass through this membrane but impurities can’t. R/O’s have an added feature of having some water wash over those membranes which helps to keep the membrane’s surface clean. This is the waste water we talk about.

But some impurities are so small that they do pass through the membrane and we then use resin to remove those minute amounts.
Our 4040 r/o membrane brings our tap water ppm down from 115 to about 2ppm. We can clean windows at 2ppm but we choose to put it through a resin di vessel to ‘polish’ it off to zero.

[CF Facilities]

An R/O membrane is like an air filter in your car or van engine's air intake.

The airfiter is made of a porous material that has tiny holes in it that allow air through but not dirt. So we have to change our airfilters regularly as they eventually get clogged up with the dirt they have trapped.

An R/O membrane does the same as it stops the impurities in the water passing through it like calcium and magnesium. So water molecules can pass through this membrane but impurities can’t. R/O’s have an added feature of having some water wash over those membranes which helps to keep the membrane’s surface clean. This is the waste water we talk about.

But some impurities are so small that they do pass through the membrane and we then use resin to remove those minute amounts.
Our 4040 r/o membrane brings our tap water ppm down from 115 to about 2ppm. We can clean windows at 2ppm but we choose to put it through a resin di vessel to ‘polish’ it off to zero.

I am interested in this thread too. Thanks for explanation. Just wondered what the three pre filters before my ro do. My tap tds is about 350 and my filters are about a year old now but I only filter about 400l of pure a week. Are they due a change.

[mike1986]

Thanks alot guys, i get it now  Just measured my tap water and its 160! This is something i'm going to have to look into i think.

[3 Wheel Windy (Retired)]

How much water do you use Mikeleek? I am only part time and still building work so only using small amounts I got 2 di 11ltrs vessels and my tds is around 150 so plan to go double di until I need to use RO.. I too know nowt about RO systems. So will keep an eye on this thread.   

[home6442]

An R/O membrane is like an air filter in your car or van engine's air intake.

The airfiter is made of a porous material that has tiny holes in it that allow air through but not dirt. So we have to change our airfilters regularly as they eventually get clogged up with the dirt they have trapped.

An R/O membrane does the same as it stops the impurities in the water passing through it like calcium and magnesium. So water molecules can pass through this membrane but impurities can’t. R/O’s have an added feature of having some water wash over those membranes which helps to keep the membrane’s surface clean. This is the waste water we talk about.

But some impurities are so small that they do pass through the membrane and we then use resin to remove those minute amounts.
Our 4040 r/o membrane brings our tap water ppm down from 115 to about 2ppm. We can clean windows at 2ppm but we choose to put it through a resin di vessel to ‘polish’ it off to zero.

I am interested in this thread too. Thanks for explanation. Just wondered what the three pre filters before my ro do. My tap tds is about 350 and my filters are about a year old now but I only filter about 400l of pure a week. Are they due a change.

The pre filters are there to protect the R.O. without them it wouldn't last long.
You will have as follows.
Sediment filter....This filters out dirt and sand which would quickly clog the R.O.
Carbon block.....This removes chlorine which destroys R.O. membranes very quickly.
GAC filter........ This protects against higher levels of chlorine.
They all have a lifespan measured in the amount of litres of water which can pass through them before
needing changed. This will depend on the make of filter you buy.
Im not sure on this one but there might be a time limit on them from when they first get used.
I personally wouldn't let them go a year without changing.

[Spruce]

An R/O membrane is like an air filter in your car or van engine's air intake.

The airfiter is made of a porous material that has tiny holes in it that allow air through but not dirt. So we have to change our airfilters regularly as they eventually get clogged up with the dirt they have trapped.

An R/O membrane does the same as it stops the impurities in the water passing through it like calcium and magnesium. So water molecules can pass through this membrane but impurities can’t. R/O’s have an added feature of having some water wash over those membranes which helps to keep the membrane’s surface clean. This is the waste water we talk about.

But some impurities are so small that they do pass through the membrane and we then use resin to remove those minute amounts.
Our 4040 r/o membrane brings our tap water ppm down from 115 to about 2ppm. We can clean windows at 2ppm but we choose to put it through a resin di vessel to ‘polish’ it off to zero.

I am interested in this thread too. Thanks for explanation. Just wondered what the three pre filters before my ro do. My tap tds is about 350 and my filters are about a year old now but I only filter about 400l of pure a week. Are they due a change.

The pre filters are there to protect the R.O. without them it wouldn't last long.
You will have as follows.
Sediment filter....This filters out dirt and sand which would quickly clog the R.O.
Carbon block.....This removes chlorine which destroys R.O. membranes very quickly.
GAC filter........ This protects against higher levels of chlorine.
They all have a lifespan measured in the amount of litres of water which can pass through them before
needing changed. This will depend on the make of filter you buy.
Im not sure on this one but there might be a time limit on them from when they first get used.
I personally wouldn't let them go a year without changing.

Well explained John.

We also need to add that the water to be filtered has to be forced through the membranes under pressure. In most cases ordinary household tap water pressure is sufficient. In our case our tap water pressure is 50psi at the moment. At this pressure the filtration process isn't as fast or efficient as it would be at say 80psi, but the performance is acceptable for us.

[mike1986]

How much water do you use Mikeleek? I am only part time and still building work so only using small amounts I got 2 di 11ltrs vessels and my tds is around 150 so plan to go double di until I need to use RO.. I too know nowt about RO systems. So will keep an eye on this thread.   

well at the moment im using about 150 litres per day working 4 days a week, but i only wfp the top windows and trad the bottoms. So its guna be at least double that amount when i switch to doing all windows wfp.

[richard jagger]

Spruce is absolutely correct if the pressure is to low you will have a high volume of waste water.as the membrane is inclined to reject more than it will pass through the membrane.