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Intended Use Only
A manufacturer's equipment has been designed for a specific use. Because of product liability laws, the manufacturer has done testing to ensure its safe as long the consumer uses the equipment for it's intended use. A home use RO system has been designed with specific design assumptions, namely to remove impurities found in poor quality potable water, i.e. drinking water. But the assumption is that the water is still drinkable. I heard about a guy who went to a government auction and bought expired Civil Defense food supplies. The government stamped "NOT FIT FOR HUMAN CONSUMPTION" on the food cartons. The expired food was meant for farmers, such as pig farmers to feed their pigs. He fed it to his family and they all got food poisoning. If the equipment could be used for multiple purposes, the manufacturer would have marketed it as such to make a profit. Product liability laws put manufacturers at risk if the products they sell aren't safe; the manufacturers will forfeit money. You can use a product not meant for its intended use, but you do so at a higher risk, you might forfeit your life. You can't use this for your outdoor RO unit and filter freshwater streams either. The manufacturer can not guarantee the safety of the water. There is a big difference between freshwater and seawater. Freshwater fishes absorbs water through their skins via osmosis since their bodies have a high salt content then the freshwater they swim in. Saltwater fishes must swallow seawater down to force the reverse osmosis process. Fair Winds, Clyde
A manufacturer's equipment has been designed for a specific use. Because of product liability laws, the manufacturer has done testing to ensure its safe as long the consumer uses the equipment for it's intended use. A home use RO system has been designed with specific design assumptions, namely to remove impurities found in poor quality potable water, i.e. drinking water. But the assumption is that the water is still drinkable. I heard about a guy who went to a government auction and bought expired Civil Defense food supplies. The government stamped "NOT FIT FOR HUMAN CONSUMPTION" on the food cartons. The expired food was meant for farmers, such as pig farmers to feed their pigs. He fed it to his family and they all got food poisoning. If the equipment could be used for multiple purposes, the manufacturer would have marketed it as such to make a profit. Product liability laws put manufacturers at risk if the products they sell aren't safe; the manufacturers will forfeit money. You can use a product not meant for its intended use, but you do so at a higher risk, you might forfeit your life. You can't use this for your outdoor RO unit and filter freshwater streams either. The manufacturer can not guarantee the safety of the water. There is a big difference between freshwater and seawater. Freshwater fishes absorbs water through their skins via osmosis since their bodies have a high salt content then the freshwater they swim in. Saltwater fishes must swallow seawater down to force the reverse osmosis process. Fair Winds, Clyde
Sorry Clyde
Freshwater fish make a huge amount of dilute urine and their main problem is the loss of electrolytes they almost never drink. Their gills catch ions and pull them into their bloodstream they also gets some in their diet. Saltwater fishes main problem is dehydration. They drink a lot and their kidneys actively excrete the excess ions into concentrated urine. Their gills may play a role. All of this is driven by osmotic pressure which is the "desire" of water to move to a place of lesser concentration of water. In the freshwater fishes water is less concentrated in the fish. In the saltwater fish water is less concentrated in seawater. It takes a lot of energy to move ions against a gradient. The only thing that uses more energy when just sitting around than kidneys in humans is our brain!!! The balance of ions is also important. This osmotic pressure can be measured in lbs/square inch and across a semipermeable membrane can be reversed by applying a greater pressure. There just isn't much pressure to overcome when you are using RO to get rid of a low concentration of ions. To do RO in saltwater the membranes must be much stronger to withstand the greater pressure required. Water that passes through a RO membrane is sterile as even viruses are huge compared to something like a sodium ion and bacteria are huge compared to viruses. I think that a 0.22 micrometer pore size is considered safe for sterilizing fluids. A RO membrane is much smaller.
Freshwater fish make a huge amount of dilute urine and their main problem is the loss of electrolytes they almost never drink. Their gills catch ions and pull them into their bloodstream they also gets some in their diet. Saltwater fishes main problem is dehydration. They drink a lot and their kidneys actively excrete the excess ions into concentrated urine. Their gills may play a role. All of this is driven by osmotic pressure which is the "desire" of water to move to a place of lesser concentration of water. In the freshwater fishes water is less concentrated in the fish. In the saltwater fish water is less concentrated in seawater. It takes a lot of energy to move ions against a gradient. The only thing that uses more energy when just sitting around than kidneys in humans is our brain!!! The balance of ions is also important. This osmotic pressure can be measured in lbs/square inch and across a semipermeable membrane can be reversed by applying a greater pressure. There just isn't much pressure to overcome when you are using RO to get rid of a low concentration of ions. To do RO in saltwater the membranes must be much stronger to withstand the greater pressure required. Water that passes through a RO membrane is sterile as even viruses are huge compared to something like a sodium ion and bacteria are huge compared to viruses. I think that a 0.22 micrometer pore size is considered safe for sterilizing fluids. A RO membrane is much smaller.
sherlock holmes???
Because "de Salinization" of sea water is run at a much higher pressure and our plastic unit cannot handle that. You would need a stainless steal constructed unit, which is part of the reason they cost so much. Customer Service Team Watts Premier Inc. TUrns out, it's the palstic vs. the stainless components...direct fromt he manufacturer. So, I will buy a unit, replace the plastic with stainless of the appropriate thickness and size...and for (my guess) under $500 have a water maker!!!!
Because "de Salinization" of sea water is run at a much higher pressure and our plastic unit cannot handle that. You would need a stainless steal constructed unit, which is part of the reason they cost so much. Customer Service Team Watts Premier Inc. TUrns out, it's the palstic vs. the stainless components...direct fromt he manufacturer. So, I will buy a unit, replace the plastic with stainless of the appropriate thickness and size...and for (my guess) under $500 have a water maker!!!!
Tom (Bham)
RO membranes are NEVER used solely for "sterility purposes" as such membranes are FULL of defects ... defects that may be much larger than 0,2µM. Current manufacturing processes simply cannot make an RO membrane that's "integral" and is 'validatable' (an FDA requirement for sterility); simple 0,2µM filter membranes can be integral and validatable. ANY time that a RO membrane is used in a 'FDA validated' sterile process its ALWAYS followed by an integral and validated 0,2uM filter because of the inherent 'defects' in RO membranes.
RO membranes are NEVER used solely for "sterility purposes" as such membranes are FULL of defects ... defects that may be much larger than 0,2µM. Current manufacturing processes simply cannot make an RO membrane that's "integral" and is 'validatable' (an FDA requirement for sterility); simple 0,2µM filter membranes can be integral and validatable. ANY time that a RO membrane is used in a 'FDA validated' sterile process its ALWAYS followed by an integral and validated 0,2uM filter because of the inherent 'defects' in RO membranes.
Tom h
Yup stainless is required for the high pressures required for desalinization. 1. the pressure is quite harmful if the 'stainless' is unable to contain that pressure .... this is not an easy or safe thing for a DIYer to do. Do you KNOW what you are doing with high pressure piping design? 2. Once you develope your materials list, and price-out the Stainless (especially in todays metal market prices for 'stainless') ... please report back to us on how much MORE your cost is in comparison to a 'ready-made' watermaker. I think you're in for a real 'eye-opener'.
Yup stainless is required for the high pressures required for desalinization. 1. the pressure is quite harmful if the 'stainless' is unable to contain that pressure .... this is not an easy or safe thing for a DIYer to do. Do you KNOW what you are doing with high pressure piping design? 2. Once you develope your materials list, and price-out the Stainless (especially in todays metal market prices for 'stainless') ... please report back to us on how much MORE your cost is in comparison to a 'ready-made' watermaker. I think you're in for a real 'eye-opener'.
Don't know much about the Costco unit
but it seems to me is intended for home use to perhaps filter well water. I don't think it would last long or do a good job of filtering salt water. You may be missing that there is good drinking water in the Caribbean and the fact that it also rains there quite frequently. If you want to carry a manual watermaker to make a couple of gallons a day to be used mainly as an emergency I think they sell for about $700. One saved Bill Butler's life when his boat was sunk in the Pacific by a whale.
but it seems to me is intended for home use to perhaps filter well water. I don't think it would last long or do a good job of filtering salt water. You may be missing that there is good drinking water in the Caribbean and the fact that it also rains there quite frequently. If you want to carry a manual watermaker to make a couple of gallons a day to be used mainly as an emergency I think they sell for about $700. One saved Bill Butler's life when his boat was sunk in the Pacific by a whale.
RichH it depends
If you are wanting absolute sterility you might be right. FDA standards for injectable fluids are very high. But for drinking water purposes I think that RO water can be considered "sterile". Now if there was a cholera epidemic going on nearby I might think about it for a while. But if I was taking relatively clean water and polishing it before consumption it would be alright for me. It takes a pretty good dose of bacteria or viruses to make you sick. Most of them die in the stomach's acid. Most of the water that comes out of most people's municiple water taps isn't "sterile" a better word might be sanitary. Well water is usually full of bacteria and many people drink well water without treatment. I've drank out of mountain streams and springs without ill effects. I've even eaten raw oysters!!!!! They make their living filtering bacteria and algea out of the water. Of course raw oysters from an area where there is a cholera outbreak could be deadly. Finally we always get some water in our mouths and noses when swimming. Usaully there is no ill effect from ingesting these small amounts of contaminated water. Just hope that no one nearby is pumping their $hit overboard.
If you are wanting absolute sterility you might be right. FDA standards for injectable fluids are very high. But for drinking water purposes I think that RO water can be considered "sterile". Now if there was a cholera epidemic going on nearby I might think about it for a while. But if I was taking relatively clean water and polishing it before consumption it would be alright for me. It takes a pretty good dose of bacteria or viruses to make you sick. Most of them die in the stomach's acid. Most of the water that comes out of most people's municiple water taps isn't "sterile" a better word might be sanitary. Well water is usually full of bacteria and many people drink well water without treatment. I've drank out of mountain streams and springs without ill effects. I've even eaten raw oysters!!!!! They make their living filtering bacteria and algea out of the water. Of course raw oysters from an area where there is a cholera outbreak could be deadly. Finally we always get some water in our mouths and noses when swimming. Usaully there is no ill effect from ingesting these small amounts of contaminated water. Just hope that no one nearby is pumping their $hit overboard.
It only take ONE or TWO clostridium cells .....
to release its toxins to either make you extremely (neurologically) sick .... or even kill you. Its all 'strain' dependent ... and there are more potent clostridiums than botulinum. All are common in marine sediments, etc. http://www.who.int/csr/delibepidemics/clostridiumbotulism.pdf ... then remember that ALL RO membranes have inherent 'cracks' in thier structure.
to release its toxins to either make you extremely (neurologically) sick .... or even kill you. Its all 'strain' dependent ... and there are more potent clostridiums than botulinum. All are common in marine sediments, etc. http://www.who.int/csr/delibepidemics/clostridiumbotulism.pdf ... then remember that ALL RO membranes have inherent 'cracks' in thier structure.
Rich h : I should be dead!!!
We all should be dead!!! Or would be dead if all it normally takes is 1-2 bacteria to produce an infection. Water from our taps isn't sterile!!! The food we eat isn't sterile. But I do agree that RO water isn't sterile. But the bacterial count should be reduced. If the RO membranes were perfect the water would be sterile. If I was drinking RO water that I was worried about being contaminated I'd add some chlorine. The biggest problem with chlorine is that it produces cancer causing by products. If you are out in the world the most likely way to get sick is from dirty hands. Dirty fruits and vegetables are a problem and if in doubt only eat cooked food. Dirty water can be a real problem!!!! But I would drink RO water that came from a clean lake. It is a little risky but probably safer than raw oysters or a fresh garden salad. Remeber that most bacteria are not free swimming but are attached to larger aggregates. These aggregates are mostly removed by the prefilters that are used in most RO systems. The the RO membrane itself should remove most remaining bacteria. So unless your feed water is heavily contaminated the final bacteria count of the water should be quite low. Most people on this planet drink water from streams,lakes,wells and springs that is not treated at all. Some get sick but most live. My wife's grandfather drank untreated well water all of his life...but he did die when he was 95.
We all should be dead!!! Or would be dead if all it normally takes is 1-2 bacteria to produce an infection. Water from our taps isn't sterile!!! The food we eat isn't sterile. But I do agree that RO water isn't sterile. But the bacterial count should be reduced. If the RO membranes were perfect the water would be sterile. If I was drinking RO water that I was worried about being contaminated I'd add some chlorine. The biggest problem with chlorine is that it produces cancer causing by products. If you are out in the world the most likely way to get sick is from dirty hands. Dirty fruits and vegetables are a problem and if in doubt only eat cooked food. Dirty water can be a real problem!!!! But I would drink RO water that came from a clean lake. It is a little risky but probably safer than raw oysters or a fresh garden salad. Remeber that most bacteria are not free swimming but are attached to larger aggregates. These aggregates are mostly removed by the prefilters that are used in most RO systems. The the RO membrane itself should remove most remaining bacteria. So unless your feed water is heavily contaminated the final bacteria count of the water should be quite low. Most people on this planet drink water from streams,lakes,wells and springs that is not treated at all. Some get sick but most live. My wife's grandfather drank untreated well water all of his life...but he did die when he was 95.
Tom, did you miss the memo? If it looks too good..
Most of us got the memo "If it looks too good to be true, it probably is." A HOME UNIT designed to be run off relatively cheap home AC 24x7 filling a 3-gallon can with a 25-gallon-in-24-hours filter limit is not designed for marine use. "So, I will buy a unit, replace the plastic with stainless of the appropriate thickness and size...and for (my guess) under $500 have a water maker!!!! " Yeah, and from looking at their parts, first you're going to spend about $1800 in having stainless welded up. Maybe more for the tight tolerances required to make some things fit. Then when you are done...you'll have maybe 1/4 of the capacity of a marine unit, at least, until the residual salt that this unit doesn't flush causes it to clog and fail. You'll save a lot of time and money and make a lot less trash by purchasing a manually operated marine unit and getting an hour of exercise every day.
Most of us got the memo "If it looks too good to be true, it probably is." A HOME UNIT designed to be run off relatively cheap home AC 24x7 filling a 3-gallon can with a 25-gallon-in-24-hours filter limit is not designed for marine use. "So, I will buy a unit, replace the plastic with stainless of the appropriate thickness and size...and for (my guess) under $500 have a water maker!!!! " Yeah, and from looking at their parts, first you're going to spend about $1800 in having stainless welded up. Maybe more for the tight tolerances required to make some things fit. Then when you are done...you'll have maybe 1/4 of the capacity of a marine unit, at least, until the residual salt that this unit doesn't flush causes it to clog and fail. You'll save a lot of time and money and make a lot less trash by purchasing a manually operated marine unit and getting an hour of exercise every day.
Hi Red, yep I got the memo..it's true
I don't think that a home unit will work for saltwater. But it might clean up clean lake water or even better water from your tanks to get rid of the awful plastic taste. If I should buy a unit it will be to treat tap water before it goes into my tanks and/or treat water from my tanks before I drink it. If I ever get to go cruising I will probably try to catch rainwater and/or some sort of solar still. Distilled water should be almost sterile as the heat should kill almost anything. Rainwater will need some bleach. Right now on my boat we drink bottled water and use tank water for washing only. You can buy a lot of bottled water at Wal-mart for the cost of a RO unit. Merry Christmas to All and may god bless us everyone!!!!
I don't think that a home unit will work for saltwater. But it might clean up clean lake water or even better water from your tanks to get rid of the awful plastic taste. If I should buy a unit it will be to treat tap water before it goes into my tanks and/or treat water from my tanks before I drink it. If I ever get to go cruising I will probably try to catch rainwater and/or some sort of solar still. Distilled water should be almost sterile as the heat should kill almost anything. Rainwater will need some bleach. Right now on my boat we drink bottled water and use tank water for washing only. You can buy a lot of bottled water at Wal-mart for the cost of a RO unit. Merry Christmas to All and may god bless us everyone!!!!
There might be hope yet for low-cost RO units....
I agree with previous posters that the low-cost RO (Reverse Osmosis) units sold to improve the quality of tap water at home, or even fresh water from open natural sources, cannot generate high enough pressures to push water across a semipermable membrane against the high osmotic pressure gradient created by seawater. Recently, however, an FO (Forward Osmosis) technology was introduced into the form of sachets with (approx. 100 ml?) of concentrated syrup solution which can be exposed to seawater in a special plastic container in order to suck enough water across a semipermeable membrane to produce about 500 ml of a nutritious sweet drink; e.g. for people in liferafts. This intriguing invention is marketed under the brand name of Sea-Pack (see link). I apologize in case this has already been mentioned on this board and also want to state that I have no connections whatsoever with the company marketing these clever devices. My prime reason for bringing this up here, however, is that it may be possible to take a low-cost RO-type device and prime its outlet with a fairly concentrated sugar solution while running seawater into the regular inlet. If one is lucky enough to have an RO device with a semipermeable membrane that does not get damaged/destroyed by this operation, while also making sure that the outlet side remains continuously primed by the sugar solution, it just might turn out to be possible to handle more concentrated salt solutions then what the RO unit was designed for while simultaneously generating less concentrated sugar solutions than produced by FO alone (not everyone has a hankering for extremely sweet drinks). In other words, a judicious combination of RO and FO principles might just do the trick..... Have I tried it myself?? NO! Is it possible that you might ruin your (low-cost) RO unit? YES! So don't blame me if that happens. On the other hand, you might be the first to prove this possible; well before it is likely to be shown on MYTH-BUSTERS! Have fun (and keep us posted) Flying Dutchman
I agree with previous posters that the low-cost RO (Reverse Osmosis) units sold to improve the quality of tap water at home, or even fresh water from open natural sources, cannot generate high enough pressures to push water across a semipermable membrane against the high osmotic pressure gradient created by seawater. Recently, however, an FO (Forward Osmosis) technology was introduced into the form of sachets with (approx. 100 ml?) of concentrated syrup solution which can be exposed to seawater in a special plastic container in order to suck enough water across a semipermeable membrane to produce about 500 ml of a nutritious sweet drink; e.g. for people in liferafts. This intriguing invention is marketed under the brand name of Sea-Pack (see link). I apologize in case this has already been mentioned on this board and also want to state that I have no connections whatsoever with the company marketing these clever devices. My prime reason for bringing this up here, however, is that it may be possible to take a low-cost RO-type device and prime its outlet with a fairly concentrated sugar solution while running seawater into the regular inlet. If one is lucky enough to have an RO device with a semipermeable membrane that does not get damaged/destroyed by this operation, while also making sure that the outlet side remains continuously primed by the sugar solution, it just might turn out to be possible to handle more concentrated salt solutions then what the RO unit was designed for while simultaneously generating less concentrated sugar solutions than produced by FO alone (not everyone has a hankering for extremely sweet drinks). In other words, a judicious combination of RO and FO principles might just do the trick..... Have I tried it myself?? NO! Is it possible that you might ruin your (low-cost) RO unit? YES! So don't blame me if that happens. On the other hand, you might be the first to prove this possible; well before it is likely to be shown on MYTH-BUSTERS! Have fun (and keep us posted) Flying Dutchman
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