Will this Watermaker Work on a Boat? It's Cheap!

[MarkJ]

Hi Folks

While wandering the streets of Egypt I saw this stype of Reverse Osmosis watermaker.
They sell in the USA for about $200 (not $2,000)

They are designed for well water and bad domestic water.
Obviously they don't have the high preseure pump of a marine system. The one I looked at had a pump similar to a Jabsco or Shure at about 50 psi wihc we have on the boat for the normal fresh water system.

On well water they claim 50 gallons - 200 liters epr day

Could a watermaker like this be used susesfully on a boat at a reduced production rate? I would be happy with 20 litres per day.

Thoughts?

Reverse Osmosis Water Filters and Water Purification

Good stats on this one
ClearChoice reverse osmosis (RO) water filter system

[Stillraining]

Worth a call to them to find out..1-866-376-2690....they might recomend this one though..

http://www.home-water-purifiers-and-...osmosis-uv.php

And you will probably need one of these as well.

http://www.home-water-purifiers-and-...oster-pump.php

[Nauticatarcher]

No it wont work, They are designed to remove impurities from fresh water, if you run a normal Seawater membrane in Brackish water you need to be able to drop your pressure right back to keep output inside rated flow of membrane as otherwise you will damage it

[Canibul]

when I was looking into setting up an RO here at the house, I found out that the cheaper ones, that will purify mucky fresh water, only need pumps, vessels, and fittings that can handle around 250 p.s.i. the ones that desalinate sea water have to have pumps, fittings, hoses, etc. that can operate at 1,000 p.s.i. Plus the components have to be able to handle the corrosive environment of salt water.

Thats where the price differences come in. Big diff between purifiers and desalinators although both can use differentially permeable membrane technology.

[NoTies]

Sorry to disappoint Mark but it definitely won't work in seawater. Brackish water membranes are not designed to remove the amount of dissolved solids necessary to make seawater (around 34000 ppm) drinkable. The membranes needed to achieve this generally operate at 800psi which requires a high pressure (expensive) pump. Seawater membranes typically start producing at around 400 psi but this water is not good quality water. With RO, the higher the pressure the higher the production rate and the better the water quality. Until such time as you destroy the membrane!!.

[bill good]

OK here's one thought that has buzzed about my empty head for some time.My usage is 20ltrs per day & I have 200ltrs fresh water so add the 20ltrs of sea water & the process 220ltrs of brackish water & I've just invented how to make fresh water for $200.00!! Also reduced the whole maintenance issue with the high pressure systems.Remember you read it here first!!!.
Now where did I leave my pipe with my hash mix?

Mark keep out of those back streets!!

[Canibul]

You're gonna look reasonably smart for the first 20 gallons of fresh water....perhaps. to the untrained eye...

but what you have really done is pollute 180 gallons of fresh water, and paid $200 to do it.

Then when you add that second 20 gallons of sea water...and the third 20 gallons....then eventually you find out how much it costs to fix the cheap RO....

I might have been born on a Tuesday, but it wasn't LAST Tuesday...

[bill good]

You missed the point!! The 200ltrs you started with is processed with 20ltrs of seawater for total of 220ltrs of potable water & you use the extra 20ltrs then add the replacement 20ltrs of seawater & repeat the process. Solved all the worlds water problems as well. You can all now send your money to my mail box.

[Stillraining]

Might just work..

But you are re-processing 220 gal every time you use 20..

It would be an interesting experiment....Mark?..

[bill good]

It may not need to be a 10:1 ratio & the power needed at low pressures appear to be better that some hi power pump figures.
Come on keep the thoughts coming!!
We are on to a good thing here.

[Stillraining]

True... but you would need a second complete backup unit, as you are effectively contaminating your whole water supply every few days....unless you could rig a metering/siphoning system to mix the predetermined amount of sea water each process, so if the unit goes belly up you still have your uncontaminated source to live off of.

[witzgall]

Watermakers discharge something like 10x (maybe more?) of the water they process. This is what keeps the salt out fo the membrane. So you would end up with about 22 gallons of potable water, the rest you would be throwing overboard. If you pumped the discharge back into the tank, you would just be running a very expensive circulation pump, and it would ruin the membrane is short order.

Chris

Originally Posted by bill good

You missed the point!! The 200ltrs you started with is processed with 20ltrs of seawater for total of 220ltrs of potable water & you use the extra 20ltrs then add the replacement 20ltrs of seawater & repeat the process. Solved all the worlds water problems as well. You can all now send your money to my mail box.

[Stillraining]

Ah!...I forgot about that part as well.

[bill good]

Still not quite on the same wave length!! Looking at the brackish water systems with low pressure filters & pumps they are not so effected by Cl products in fact they are used to filter them out. Not the same as high pressure RO system. A system on a boat could be a split system of two tanks for reserve supply. Will just have to go & do it (after I fix up all the outstanding jobs). I remember reading where some folks drifting for months drank a little salt water each day along with fresh just to replace elements missing from their diets.

[Canibul]

I can't see any way that adding denser salt water to a fresh water RO system is going to work in the long run. You are adding the very contaminant that you are trying to remove. That's like saying a little aresnic can kill you and the andidote is a lot more arsenic. (hmmm...do RO systems puke?)

Hey, did you by any chance used to be a Nigerian Government Minister's widow? I think we had some email exchanges a while back...