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Watermakers
Can any of these systems be used on a boat?
http://www.pure-earth.com/ro.html Thanks, Jeannette aa6jh Bristol 32, San Carlos, Mexico http://www.eblw.com/contepartiro/contepartiro.html |
jeannette wrote in
: Can any of these systems be used on a boat? http://www.pure-earth.com/ro.html No, these systems are designed to be used with potable water, not sea water. RO systems for seawater run at 800+ PSI. -- Geoff |
So where do you get a pump like that? Can it run off the battery or do you need to start the motor? I only need a couple of gallons a day. Any ideas for budget DIYer's. I saw that one guys awsome setup who posts here but I think it's a little ambitious for me. That was probably me. You really can't do it for less than around a Boatbuck ($1K). The basic equipment remains pretty much the same from a single 24" membrane producing 5 gallons an hour to a double 40" like mine producing 35 gallons an hour. It just takes more membranes and a larger pump. You can run a pump on 12V but as Geoff has found you run into a practical limit of how much water you can make. Even then you really need to be running the engine. A 1/4 HP pump will draw 15 or more amps -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
Don't see why they would not work in lake water, with a pre filter/strainer
of some kind to remove junk, and an ultraviolet sterilizer after the unit to get rid of bacteria. Salt water would probably be too much. Frank "jeannette" wrote in message ... Can any of these systems be used on a boat? http://www.pure-earth.com/ro.html Thanks, Jeannette aa6jh Bristol 32, San Carlos, Mexico http://www.eblw.com/contepartiro/contepartiro.html |
Frank wrote: Don't see why they would not work in lake water, with a pre filter/strainer of some kind to remove junk, and an ultraviolet sterilizer after the unit to get rid of bacteria. Salt water would probably be too much. Frank If you're relying on UV to sanitize the water, you'd better plan on a recirculation system that runs continuously - not really desireable in boating application. UV is a very poor sanitizer, especially in a one-pass installation. Keith Hughes |
Pure Earth http://www.pure-earth.com/ sells what look like very efficient
high intensity one pass sanitizers. I have only looked at the specs, they look good. Of course, specs and reality may be different. "Keith Hughes" wrote in message ... Frank wrote: Don't see why they would not work in lake water, with a pre filter/strainer of some kind to remove junk, and an ultraviolet sterilizer after the unit to get rid of bacteria. Salt water would probably be too much. Frank If you're relying on UV to sanitize the water, you'd better plan on a recirculation system that runs continuously - not really desireable in boating application. UV is a very poor sanitizer, especially in a one-pass installation. Keith Hughes |
"Frank" wrote in
: Don't see why they would not work in lake water, with a pre filter/strainer of some kind to remove junk, and an ultraviolet sterilizer after the unit to get rid of bacteria. Salt water would probably be too much. Frank Bacteria won't go through the membrane on an RO system.....however, as bacteria collect on the high side of the membrane, they die and break apart, releasing their toxins. The toxins, unfortunately, DO pass through the membrane making the outlet water toxic to humans. I doubt ultraviolet light has any effect on the toxins, which aren't alive. RO people don't like to talk about bacterial breakdown causing people to get sick drinking RO water..... I only tell you this because I'm a DISTILLER water person, here....(c; I'm down to 3.8 ppm total dissolved solids in my output. The taste and the coffee it makes is superb... NOTHING sanitizes like STEAM. RO is STILL just a filter. Once the filter's clogged or something approaches the filter that's smaller than the filter's design, it enters the outlet water stream and no amount of wishing will change it.... -- Larry This jerk called my cellphone and was nasty. Continental Warranty -- MCG Enterprises -- Mepco- 24955 Pacific Coast HWY Suite C303 Malibu California 90265 888-244-0925 Fax: 310-456-8844 Email: Read about them he http://www.ripoffreport.com/view.asp...3&view=printer |
"frank" wrote in :
Pure Earth http://www.pure-earth.com/ sells what look like very efficient high intensity one pass sanitizers. I have only looked at the specs, they look good. Of course, specs and reality may be different. Easy to test.... Pump holding tank water into the RO's inlet. Put a glass under the outlet. Have the sales wienie drink it. Wait 2 hours for the results before getting out your checkbook....(c; FYI, Ashley River water distills quite nicely (brackish with treated sewage), but makes a tougher cleanup of the boiler after a few gallons. I can't tell any difference in the taste even though the total dissolved solids goes up to 12-15 ppm, which is nothing.... The residue looks like pluff mud and salt crystals. -- Larry This jerk called my cellphone and was nasty. Continental Warranty -- MCG Enterprises -- Mepco- 24955 Pacific Coast HWY Suite C303 Malibu California 90265 888-244-0925 Fax: 310-456-8844 Email: Read about them he http://www.ripoffreport.com/view.asp...3&view=printer |
Having spent a fair amount of time trying to validate such systems in
pharmaceutical water plants, I'm highly dubious. It can be done, at small flow rates and long exposures, but it is *sanitization* not sterilization. Bacteria are fairly adept at repairing UV induced damage. And UV doesn't kill the bacteria, typically, just makes them unable to reproduce. And, as Larry pointed out, you still have issues with endotoxins that can permeate the membranes. Maintenance is always critical with RO systems, as the pressure increases as you form a biofilm on the membranes, making leaks more common (o-rings, membrane cracks/perforations, etc.). Once you get that leak, then you have tons of critters cruising through, enough to make you sick even if they can't reproduce. IMO, relying on RO to take care of water that has too high a bioburden to drink otherwise is asking for trouble. Keith Hughes frank wrote: Pure Earth http://www.pure-earth.com/ sells what look like very efficient high intensity one pass sanitizers. I have only looked at the specs, they look good. Of course, specs and reality may be different. "Keith Hughes" wrote in message ... |
Keith Hughes wrote in
: Having spent a fair amount of time trying to validate such systems in pharmaceutical water plants, I'm highly dubious. It can be done, at small flow rates and long exposures, but it is *sanitization* not sterilization. Bacteria are fairly adept at repairing UV induced damage. And UV doesn't kill the bacteria, typically, just makes them unable to reproduce. Keith, I noticed these small RO systems put in boats use quite a bit more pressure than the commercial units, say for a muni water system. Wouldn't that make them break down the dead bacterium much faster, releasing their toxins into the water supply? -- Larry This jerk called my cellphone and was nasty. Continental Warranty -- MCG Enterprises -- Mepco- 24955 Pacific Coast HWY Suite C303 Malibu California 90265 888-244-0925 Fax: 310-456-8844 Email: Read about them he http://www.ripoffreport.com/view.asp...3&view=printer |
Larry,
Keith, I noticed these small RO systems put in boats use quite a bit more pressure than the commercial units, say for a muni water system. Wouldn't that make them break down the dead bacterium much faster, releasing their toxins into the water supply? I doubt it. The water bugs that create the biofilm are pretty tolerant of pressure, they just balance internal and exterior pressure. Hardy little beasts. I would certainly expect a higher level of membrane compaction, shortening the life, and a much greater propensity for o-ring and membrane failure. The additional pressure will, of course, help move any cellular debris through any holes, including the membrane 'pores'. Most of the commercial systems I've dealt with operate closer to 600-650 psig, and they still have leakage problems. Keith |
Keith Hughes wrote in
: to 600-650 psig, and they still have leakage problems. I love my distillers.... I love my distillers.... I love my distillers.... I love my distillers.... I love my distillers.... -- Larry This jerk called my cellphone and was nasty. Continental Warranty -- MCG Enterprises -- Mepco- 24955 Pacific Coast HWY Suite C303 Malibu California 90265 888-244-0925 Fax: 310-456-8844 Email: Read about them he http://www.ripoffreport.com/view.asp...3&view=printer |
On Sun, 10 Jul 2005 20:47:35 -0400,
Larry wrote: Keith Hughes wrote in : to 600-650 psig, and they still have leakage problems. I love my distillers.... I love my distillers.... I love my distillers.... I love my distillers.... I love my distillers.... How much power does it take to make a gallon of fresh water from seawater with your distillers? -- Jim Richardson http://www.eskimo.com/~warlock Silence is one of the most effective forms of communication. |
I am not sure either of you guys has any idea what goes on inside a R/O
pressure vessel. First of all the normal pressure range for a seawater system is between 750 and 850PSI. Seawater R/O membranes are made from completely different materials and construction from municipal and most other industrial purification membranes. They can withstand pressures almost twice that high. Unless they are damaged by chlorine they don't leak. The only O-ring that might potentially leak brine into the product is at the output end of the product tube. Any leakage there would immediately raise the salt level above the drinkable level. The other two O-rings seal the pressure vessel itself and when they start to leak with 800PSI behind them the result is more than a little bit noticeable. Now as to squashed bacteria. The process of reverse osmosis is not simply squeezing water through super small holes. The salt is rejected by the electrical charge of the salt ions. The charged ions are pushed away from the membrane surface. In the process bacterial is pushed away with the ions. The seawater flow across the membrane surface is 7 times that of the product flowing through it. Bacteria being several million times larger than the salt ions are swept away so they never get a chance to collect on the membrane in normal operation. If you leave the membrane idle for several days however the bacteria can settle on the membrane and start reproducing and THAT can cause clogging. What causes scaling is the accumulation of molecules of minerals with very low charge. A flush with a mild acid every couple of hundred operating hours will take care of that. Normally R/O desalinated water is 100% free of bacteria but if you are drawing from a harbor or other polluted water with a high virus count statistically some viruses can get through the membrane and that is what UV post treatment is for. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
On Sun, 10 Jul 2005 18:32:24 -0700, Jim Richardson
wrote: On Sun, 10 Jul 2005 20:47:35 -0400, Larry wrote: Keith Hughes wrote in : to 600-650 psig, and they still have leakage problems. I love my distillers.... I love my distillers.... I love my distillers.... I love my distillers.... I love my distillers.... How much power does it take to make a gallon of fresh water from seawater with your distillers? Hmmm...let's pencil in the numbers on back of an envelope. A (US) gallon of water is 8 lb that's 8/2.2 kg = 3.636kg = 3636 gm From 20 degC, it takes 80 cal to get to BP then 540 cal/gm to get to steam. Totals....3636 X (80 + 540) = 2.254 Mcal = 9.5 MJ So if you could be happy with one gal/hr, it would take 9.5 MJ.hr or 9.5MJ / 60X 60 = 2.63 kilowatts. But some or all those heating watts could maybe get returned to the feedwater from the distilled water, and that's the trick to cutting the power consumption of a still. Or how about a low vacuum process, so the water feed boils at low temp? Brian Whatcott Altus, OK |
On Mon, 11 Jul 2005 03:08:26 GMT,
Brian Whatcott wrote: On Sun, 10 Jul 2005 18:32:24 -0700, Jim Richardson wrote: On Sun, 10 Jul 2005 20:47:35 -0400, Larry wrote: Keith Hughes wrote in : to 600-650 psig, and they still have leakage problems. I love my distillers.... I love my distillers.... I love my distillers.... I love my distillers.... I love my distillers.... How much power does it take to make a gallon of fresh water from seawater with your distillers? Hmmm...let's pencil in the numbers on back of an envelope. A (US) gallon of water is 8 lb that's 8/2.2 kg = 3.636kg = 3636 gm From 20 degC, it takes 80 cal to get to BP then 540 cal/gm to get to steam. Totals....3636 X (80 + 540) = 2.254 Mcal = 9.5 MJ So if you could be happy with one gal/hr, it would take 9.5 MJ.hr or 9.5MJ / 60X 60 = 2.63 kilowatts. But some or all those heating watts could maybe get returned to the feedwater from the distilled water, and that's the trick to cutting the power consumption of a still. Or how about a low vacuum process, so the water feed boils at low temp? Brian Whatcott Altus, OK It was somewhat of a rhetorical question, but thanks for the numbers :) As an aside, while pulling a vacuum will enable lower temp distillation, I don't think you reduce your energy load any, just using a different method, which may be easier to get, (mechanical, rather than electrical) Distilation may make sense in large power boats, (read, 100' and up) with plenty of waste heat, but it's not going to work well for small sailboats. At some point, a distilation system would make more sense than an RO system, but it's going to need a fairly large vessel for that. And this ignores the issues of scaling in the boiler with salt water as feed stock. -- Jim Richardson http://www.eskimo.com/~warlock Words fail me. Thank goodness I can make gestures. -- Mark Hughes (in asr - 2001 |
Glenn Ashmore wrote: I am not sure either of you guys has any idea what goes on inside a R/O pressure vessel. Well, you'd be wrong there Glen...at least by half. First of all the normal pressure range for a seawater system is between 750 and 850PSI. If you'd followed the thread, you'd know that my response had *nothing* to do with seawater systems *in seawater*. The post I was responding to was about purifying lake water using RO followed by UV sanitization. Seawater R/O membranes are made from completely different materials and construction from municipal and most other industrial purification membranes. They can withstand pressures almost twice that high. Withstanding higher pressures is no guarantee they won't suffer from compaction and membrane/o-ring failure over time. Unless they are damaged by chlorine they don't leak. Right. I've seen a number of TFC membranes leak at lower pressures. It all depends on usage, care and feeding. The only O-ring that might potentially leak brine into the product is at the output end of the product tube. Any leakage there would immediately raise the salt level above the drinkable level. No salt in *this* discussion. The other two O-rings seal the pressure vessel itself and when they start to leak with 800PSI behind them the result is more than a little bit noticeable. Now as to squashed bacteria. The process of reverse osmosis is not simply squeezing water through super small holes. The salt is rejected by the electrical charge of the salt ions. The charged ions are pushed away from the membrane surface. In the process bacterial is pushed away with the ions. Sorry, but this does not follow. Bacteria are not pushed away from the membrane concomitant with ions. In the case of bacteria, its a mechanical exclusion, or sieving effect. The seawater flow across the membrane surface is 7 times that of the product flowing through it. Bacteria being several million times larger than the salt ions are swept away so they never get a chance to collect on the membrane in normal operation. For the most part yes, you have tangential flow. You still have impaction, and bacteria will embed and adhere to membrane surfaces. How quickly they proliferate depends on feedwater flowrate, temperature, and nutrient content. If you leave the membrane idle for several days however the bacteria can settle on the membrane and start reproducing and THAT can cause clogging. That was my point. I've seen many industrial systems running 24/7 that develop a significant biofilm. And how many boat systems run 24/7? What causes scaling is the accumulation of molecules of minerals with very low charge. A flush with a mild acid every couple of hundred operating hours will take care of that. Normally R/O desalinated water is 100% free of bacteria but if you are drawing from a harbor or other polluted water with a high virus count statistically some viruses can get through the membrane and that is what UV post treatment is for. Normally yes. With any membrane penetration, that's a problem. And UV is only effective short term, as bacteria can repair themselves within 36-48 hours following UV exposure, and exposure to visible light. Do you cycle through all your stored water in that time? And UV is ineffective against larger pathogens such as giardia and cryptosporidia - likelier to be found in lake waters. In unpolluted seawater, I wouldn't worry too much about it, but in inland lakes? RO followed by sterile filtration doubtful (organics and heavy metals dontcha know), RO alone, no thanks! Keith Hughes |
Brian Whatcott wrote in
: But some or all those heating watts could maybe get returned to the feedwater from the distilled water, and that's the trick to cutting the power consumption of a still. Or how about a low vacuum process, so the water feed boils at low temp? Brian Whatcott Altus, OK What "power"? How much "power" (heat) is available in the exhaust of a Detroit Diesel burning 20-30 gallons an hour at 30% efficiency? God, heat is EASY in a power boat....going to waste up the stacks. -- Larry This jerk called my cellphone and was nasty. Continental Warranty -- MCG Enterprises -- Mepco- 24955 Pacific Coast HWY Suite C303 Malibu California 90265 888-244-0925 Fax: 310-456-8844 Email: Read about them he http://www.ripoffreport.com/view.asp...3&view=printer |
Jim Richardson wrote in news:63b9q2-
: And this ignores the issues of scaling in the boiler with salt water as feed stock. Same as evaps in a steamship....backflush. Salt dissolves in seawater...(c; -- Larry This jerk called my cellphone and was nasty. Continental Warranty -- MCG Enterprises -- Mepco- 24955 Pacific Coast HWY Suite C303 Malibu California 90265 888-244-0925 Fax: 310-456-8844 Email: Read about them he http://www.ripoffreport.com/view.asp...3&view=printer |
On Mon, 11 Jul 2005 19:01:15 -0400,
Larry wrote: Jim Richardson wrote in news:8qu8q2- : How much power does it take to make a gallon of fresh water from seawater with your distillers? 25c at 8c/kWH from South Carolina Electric and Gouge. what do you do about the scale buildup in the distiller? Not that it matters much I suppose, since 3KW/h isn't exactly going to work on a sailboat not tied up to the dock, (and to shore power) What I can't figure out is why marine engine builders can't build a good distiller right into the engine heads. The coolant in there is BOILING, already! In yachts with dry stacks, a simple heat exchanger right in the exhaust stack would provide an amazing amount of distilled seawater in motor yachts, just like an evaporator does on a steamship. It isn't rocket science, like RO is. You need a seawater pump, already mounted on the engine that's pumping cooling water into it at some pressure, a float- regulated tank to maintain the seawater in the heat exchanger tubes perking away in the exhaust stack, and a seawater condenser using the same seawater pump on the engine to cool the steam back into distilled water. Feed that through a carbon pile filter to take out distillables like benzenes and what comes out is the freshest water in the world...no toxins, no chemicals, no bacteria leaking through tiny holes in million-dollar membranes. It would run 24/7 in a motor yacht until you ran out of tankage to store it. A backflush timer would dump the salt and residues every few hours overboard or you would have an overflow at some level to constantly lose some of the huge energy in the stack dumping it over continuously cleaning it. It's just salt and bugs and seaweed crap left over. Make it out of stainless tubes so it doesn't corrode with a zinc in it, if necessary. Distillers are FAR less complex than RO science projects....really simple devices. The boat would probably be overrun with fresh water in a yacht with twin dry-stack diesel beasts burning up 20 gallons an hour, most energy going right up that stack. yeah, and distillers make sense on big power boats, like fish processors, and lux yachts, can't see them working that way for a 35' sailboat though... -- Jim Richardson http://www.eskimo.com/~warlock I came; I saw; I ****ed up |
Jim Richardson wrote in news:clccq2-
: what do you do about the scale buildup in the distiller? We've got fairly heavy calcium buildup from city water, here. Strangely enough, the scale only builds to a certain point, then flakes off as solid calcium into the boiler, which would be easy to flush overboard. My big commercial distiller has never been descaled and works fine. The countertop Sears unit is a stainless, 1 gallon boiler you fill from the sink. Its manufacturer recommends descaling with the same acid used in coffee pots. I did it once and didn't see any difference in performance. It draws about 1100 watts for a little over 2 hours to make a gallon. I agree about sailboats having distillers. I suppose it boils (pun!) down to what you tradeoff for your health drinking RO water that may be undetectably toxic until it is too late. Isn't it odd we always hear about a hundred people on a cruise liner with RO water getting sick.....but never hear a report about what the investigators find, that may cause people to not book vacations on them? -- Larry This jerk called my cellphone and was nasty. Continental Warranty -- MCG Enterprises -- Mepco- 24955 Pacific Coast HWY Suite C303 Malibu California 90265 888-244-0925 Fax: 310-456-8844 Email: Read about them he http://www.ripoffreport.com/view.asp...3&view=printer |
Jim Richardson wrote:
yeah, and distillers make sense on big power boats, like fish processors, and lux yachts, can't see them working that way for a 35' sailboat though... If the sun is available, solar distilling could easily be used. Piece of glass (with drainage for distilled water) at an angle over a tub of salt water would work. Haven't done that my self, but it does sound like a viable DIY project. -- Katukivien alla on rantahiekkaa. |
Nuutti Gylling wrote in :
If the sun is available, solar distilling could easily be used. Piece of glass (with drainage for distilled water) at an angle over a tub of salt water would work. Navy lifeboats used to have a balloon in them. You put salt water into the bottom and blew them up. around the middle was a collection channel where the condensate dripped to with a spigot to tap it off. -- Larry This jerk called my cellphone and was nasty. Continental Warranty -- MCG Enterprises -- Mepco- 24955 Pacific Coast HWY Suite C303 Malibu California 90265 888-244-0925 Fax: 310-456-8844 Email: Read about them he http://www.ripoffreport.com/view.asp...3&view=printer |
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