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Archive 1 |
i find the latter half of the section, the part with all the citation needed marks, irrelevant to the article. I suggest it either be placed under its own article (Reverse Osmosis and it's effects??) or deleted completely. My motion's on the latter.-- Psydude 16:07, 2 June 2006 (UTC)
are you kidding?!!! the only thing you can really apply reverse osmosis to in the REAL WORLD is desolination and water purification, take it from a wastewater treatment civil engineer, leave those sections IN!
"Portable reverse osmosis (RO) water processors are sold for personal water purification in the home. These units are gravity powered (they need no water pump), and need no electricity"
I'm not aware of any gravity powered reverse osmosis system, especially not sold for home use. It's my understanding that a significant pressure is required, more than gravity could supply. I think whoever put this in was confused because most under-sink reverse osmosis systems require no pump or electricity, because there is already enough pressure in the municipal water supply. That is very different than gravity powered, which would be something like a Brita pitcher. If portable, gravity powered reverse osmosis systems were possible, I'm pretty sure they would be sold to the outdoor and marine survival markets. Currently, the desalinator included on some high end life rafts and on some boats is a hand powered device that produces about a liter an hour, with a lot of effort. -- 24.24.80.35 13:25, 16 July 2006 (UTC)
To elaborate on the pressure requirements for Reverse Osmosis, typical large scale osmosis units operate at 150 to 500 psi (Lindeburg, 1990). The static head of water (height required for gravity flow) required to operate in that range would be 346 ft to 1,150 ft, respectively. House hold taps are usually less than 100 psi, but for smaller systems this pressure may suffice. The range of pressure is due to the fact that pressure must be constantly increased to maintain a constant yield. The increased pressure is to compensate for the effects of fouling and compaction. ~Gerald B.
I removed the CAI Technologies link as the 'how to choose a system' link. If people want to add suppliers as external links I think that's fine, but identify them as such. CAI is not independent any more than Watts Premier is. 208.114.132.151 01:12, 22 August 2006 (UTC)
This article could use a History section. IIRC it's not that old of a technology.
San Diego does not currently recycle waste water back to tap water. I removed the erroneous entry about this. It has been proposed, but was rejected several years ago. The city has conducted a recent study, and the proposal is up for review by a city council committee. Mayor Jerry Sanders opposes the proposal. I find the Los Angeles statement highly suspect in light of this, but I'll leave it to a Los Angeles resident to research. News article: [1]
Dennis Chancelor did not "invent the Reverse osmosis processor" so I removed the reference. This was a very suspect statement supported only by a local newspaper interview with the supposed inventor. A US patent database search show no US patents with an inventor named Chancelor, while in contrast there are 461 US patents with "reverse osmosis system" in the claims section. These go back to 1976. Further - his name shows up nowhere in the scientific literature. I personally was building RO systems in 1970, I worked on developing the technology and several dozen products, systems and applications, from 1970 to 2005, and never heard of this person. Several of the RO commercial founders (Don Bray, Dean Spatz, J. Riley) and the early academics (S, Sourirajan, Merten, Lonsdale etc) are a few of the dozen or so people who could make some type of claim like this - although they would not because once Sourirajan invented it and GulfAtomic corporation developed it under early federal grants, R0 technology was developed in a very widespread and colloborative manner. 65.29.7.173 21:08, 6 July 2006 (UTC)David Paulson 65.29.7.173 21:08, 6 July 2006 (UTC)
Reverse osmoisis should be merged, this also should be checked for copyright violation (I will google it..) Rotem Dan 17:41 Apr 1:: Reverse osmosis (stub which is linked by Osmosis) and the misspelled 4, 2003 (UTC)
Osmosis ...reverse osmosis comes from the process of osmosis, the natural movement of solvent from an area..., in my understanding, is imprecise. Osmosis is the movement of water only not just any solvent - anything else is diffusion. 208.114.132.151 02:16, 22 August 2006 (UTC)
This is a copyright violation, I am blanking this article. see [2] Rotem Dan 17:46 Apr 14, 2003 (UTC)
It's interesting that much credit (well-deserved) is given to Loeb and Sourirajan, and yet the page states that RO membranes have no pores, a point I suspect they would disagree with given Sourirajan's development and furtherance of membrane pore models such as the Preferential Sorption-Capillary Flow Model. Perhaps this statement could be replaced with a statement such as:
The membranes used for reverse osmosis have a dense polymer barrier layer in which separaton takes place (current theory indicates transport is by diffusion through the barrier layer, known as the solution-diffusion, or through preferrential sorption pore or channel flow). —The preceding unsigned comment was added by 66.83.180.10 ( talk) 20:04, 5 December 2006 (UTC).
can the process of reverse osmosis helps to reduce the hardness or Chloride contents of D.M water for Boiler ? also whether it is useful if the intake water is highly contaminated by high sewage mix-up ? what will be the impact on processing cost compared to normal water treatment? —The preceding unsigned comment was added by Anilbapatnasik ( talk • contribs) 09:16, 16 February 2007 (UTC).
I miss in the whole article the energy consumption
New systems with pressure recovery are at 2.5 kWh electric power / m³.
Here a desalination cost calulator
When it comes to the task to reduce carbon dioxide to a level before using fossile energy, desalination for irrigation dry areas could be a key technology.
-- Pege.founder ( talk) 13:56, 2 March 2008 (UTC)
I have zero prior knowledge about RO or other water purification methods. Came to the Wikipedia RO article after reading an Associated Press article about pharmaceuticals in the water supply. (see: http://news.yahoo.com/s/ap/20080309/ap_on_re_us/pharmawater_i). In the AP article it is claimed that RO, alone amongst household water purification methods, removes pharmaceuticals.
I suggest that an excellent addition to this Wikipedia RO article would be, discussion of the effectiveness of RO at removing pharmaceuticals. i.e. 100% for any/all; vs. less than 100%; vs. not really fully researched or understood yet from an engineering/chemistry perspective; or whatever the actual situation may be.
Thanks in advance to anyone with the wherewithal to add this kind of information. Publius3 ( talk) 21:07, 9 March 2008 (UTC)
and needs to be removed. This article is about reverse osmosis, not water purification. Unless someone objects, I'd like to move wet oxidation to it's own article. Johnathlon 01:10, 28 July 2005 (UTC)
Just for your knowledge, Glaceau Vitamin Water uses the reverse osmosis water. In all the nutrient enhanced water beverages.
63.87.161.130 (
talk)
18:53, 26 March 2008 (UTC)
The intro paragraph should be a lot shorter and if possible less technical. Epl18 ( talk) 19:25, 13 September 2008 (UTC)
Seconded. The second half of the intro reads like an awkward retelling of the first half, with out providing any additional information. Ekozlenko ( talk) 19:33, 22 November 2008 (UTC)
I think some discussion of efficiency would be very helpful (and I note the comment above re energy consumption).
In specific regard to efficiency of small-scale (household, and I assume, therefore, cheap?) systems, I do not understand this sentence: "Household Reverse osmosis units use a lot of water because they have low back pressure." Or rather, I don't understand what the sentence is trying to convey. —Preceding unsigned comment added by 70.66.64.230 ( talk) 23:51, 1 September 2009 (UTC)
Removed:
This is not true - activated carbon does not "give back normal flavor" and it is usually washed and otherwise purified to avoid adding any extracttables. Water "tastes flat" once purified due to the same osmotic effect described earlier - an interaction with the fluid in the cells- taste bud cells in this case. small amounts of salts are added back to improve taste - an example ois Dasani bottled water. 65.29.7.173 15:32, 4 July 2006 (UTC)David Paulson 65.29.7.173 15:32, 4 July 2006 (UTC)
This sounds like the addition of somebody with an axe to grind. Even if it's reinserted once citations are supplied, it will need considerable work for neutrality. -- Robert Merkel 04:19, 2 July 2006 (UTC)
regarding the comments on ro being oversold and the deletion: some of these statements are common facts among ro users: ro does not remove bacteria; before going thru an ro membrane water must be pre-treated. would such comments need citations? as for neutrality, the ph level of the comments may need to be tested - ro isn't for everyone and i have one. in addition, the section on the effects of chlorine on the 2 types of ro membranes seems to state that chlorine damages both types but i am a little confused. you've deleted some important information - someone might like to be tipped off that they may need to buy a water softener and 3 or 4 filters and an electric pump to use a small under the sink reverse osmosis unit to supply the water for their refrigerator dispenser and ice maker. jm —Preceding unsigned comment added by 68.56.32.239 ( talk) 23:00, 23 October 2009 (UTC)
Can this article have some diagram or illustrative image? I like pretty pictures, not to read much text. -- Frap ( talk) 10:51, 11 August 2008 (UTC)
Text can be paraphrased and referenced. Images can be redrawn, and referenced. If Dow releases these images, that works too, but that might not be worth the effort. --
Rifleman 82 (
talk)
15:21, 4 November 2010 (UTC)
In the disadvantages section, this article states "Reverse Osmosis water is, in fact, so chemically unstable and acidic that in many countries national plumbing codes restrict water that has been filtered via reverse osmosis from being reintroduced into copper pipes due to its corrosiveness on the copper. This also has implications for reverse osmosis filtration systems that use steel storage tanks, as the acidity of the water can lead to the steel rusting over time and contaminating the post-filter water." Acidic is incorrect here. The water should be neutral, or somewhere in the vicinity of neutral, depending on the temperature. The water would be more corrosive, as it would strip/leach metals as it passes through the piping (be it steel or copper). This is due to the fact that the metals are slightly soluble in water, and normally the water is saturated, or nearly saturated with these solutes. With RO water, it is completely devoid of contaminants. As it passes through the piping, it will strip/leach whatever it can, at a relatively rapid rate. Woahmid ( talk) 18:42, 27 February 2012 (UTC)
Any body know why this is recommended by the filter Mfg. They say to replace the rO filter and let the water run for 24 hours, and Do Not Drink the water during this time; why is it dangerous? — Preceding unsigned comment added by 24.176.238.174 ( talk) 21:43, 31 January 2013 (UTC)
Reverse osmosis works by a diffusion mechanism and not a straining mechanism. There are no 'holes' in the membrane, so it works completely differently to processes such as sand filtration or even ultra filtration (which do work via straining through holes). To describe the mechanism in simple terms, RO works whereby the water molecules 'dissolve' into the membrane and then 'undissolve' out on the permeate side. Salt molecules do not 'dissolve' across the membrane as easily (but some do). This mechanism explains why some large organic molecules can cross the RO membrane more easily (since they are essentially non-polar and can dissolve into the membrane easier) than much smaller (and highly charged) salt molecules. It also explains why different RO membranes have different rejection rates for the same salt molecule, and why some small molecules more readily cross the membrane than others. To prove a point, take for example boron. At neutral pH's it exists mainly as a non-ionised species (boric acid) and membrane rejection rates are in the order of 50-75%. If the pH is increased to around 10 boric acid [B(OH)3] becomes a borate ion [B(OH)4-] and is negatively charged and rejection rates increase dramatically (>95%). Rejection increases because the ionised borate ion finds it harder to 'dissolve' into the (essentially) non-polar membrane. Note that RO membranes have a slight negative surface charge but on the whole are non-polar BluesLewis ( talk) 12:19, 20 February 2013 (UTC)
For some reason the article doesn't specifically cover how RO water is produced in labs at different qualities. For instance type 1 water is RO water filtered once. Type 2 water, which is even purer, is RO water filtered through a second RO filter. Although Type 1 water and Type 2 water are a measure of how pure the water is, I think it should be mentioned that they can be made with RO filters. Also, someone who knows how to make new Wiki articles better than me should make a Wiki article stating what Type 1 and Type 2 water are. 23.16.154.149 ( talk) 13:12, 27 February 2013 (UTC)BeeCier
Why does the article use the word solvent as if it's something other than water? Isn't the very reason that water makes up so much of our bodies- between 50 to nearly 80 percent- because it makes an excellent solvent? Or do I just need to read further into my book on anatomy and physiology? Because it calls water a solvent in chapter 3. — Preceding unsigned comment added by Thetrellan ( talk • contribs) 03:06, 14 June 2012 (UTC)
"Reverse osmosis is in the final category of membrane filtration, "hyperfiltration", and removes particles larger than 0.1 nm."
This needs to go. To quote Wolfgang Pauli, "Not only is it not right, it's not even wrong!" You can't talk about particles at the Angstrom (0.1 nm) level - quantum mechanics kicks in here in a big way. As pointed out elsewhere this isn't filtration, but a chemical/statistical mechanics force/pressure. — Preceding unsigned comment added by Waveman68 ( talk • contribs) 18:27, 29 August 2012 (UTC)
"Reverse osmosis is in the final category of membrane filtration, "hyperfiltration", and removes particles larger than 0.1 nm."
This whole paragraph should be checked for accuracy. Since 0.1 nm = 1 angstrom and the diameter of a water molecule is approximately 1.5 anstroms then the "hyperfiltration" reverse osmosis membrane should reject the passage of water molecules and so reverse osmosis could not occur. Since reverse osmosis does work, this statement can not possibly be correct. — Preceding unsigned comment added by 69.120.111.106 ( talk) 04:27, 24 November 2013 (UTC)
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I'm not seeing how the information is actually supported by the references offered. Please quote from the references. (Additionally, WP:MEDRS and WP:FRINGE apply, but let's start by verification first.) -- Ronz ( talk) 16:05, 13 April 2014 (UTC)
The article states "They come ranging from 1500 GPD (gallons per day) to 150,000 GPD and bigger depending on the need." If there are units that qualify as "and bigger" than 150,000 gallons per day, then it does not make sense to say "from 1,500 gallons per day to 150,000 gallons per day." -- Desertphile ( talk) 01:23, 20 September 2009 (UTC)
I edited the "process" section of the article by removing the description of what osmosis is from the beginning of it. If people don't have enough knowledge about osmosis to understand reverse osmosis, then they could look it up. It is not necessary to discuss it in this article.
~~ —Preceding
unsigned comment added by
76.217.12.210 (
talk)
08:22, 29 April 2011 (UTC)
"Areas that have either no or limited surface water or groundwater may choose to desalinate" is nonsense. Areas don't make choices. — Preceding
unsigned comment added by
80.5.252.34 (
talk)
07:32, 3 July 2014 (UTC)
This sentence: "Up to 50% of the seawater input can be recovered as fresh water, though lower recoveries may reduce membrane fouling and energy consumption." appears to be incorrect. Was the author trying to say that membrane fouling causes lower recovery and higher energy consumption? As written, it says that one of the effects is the cause. Could someone with a background in this please read and correct? — Preceding unsigned comment added by 155.95.80.243 ( talk) 19:45, 31 July 2015 (UTC)
"In the normal osmosis process, the solvent naturally moves from an area of high solute concentration (high water potential), through a membrane, to an area of low solute concentration (low water potential)." This is exactly backwards. In a normal osmosis process, the solvent moves from lower solute concentration to higher concentration until equilibrium is reached. — Preceding unsigned comment added by 192.234.111.8 ( talk) 19:49, 10 September 2015 (UTC)
While I'm not qualified to add the info, I'd like to see a little bit more detail regarding the efficiency of RO systems and the water costs involved (my understanding is that RO uses a large quantity of source water to 'produce' a small qty of clean water)..
Addition to note on RO design 1: the RO membrane are size to recover only 15% permeate per "membrane unit" that is correct but it also can connect to series and do water recycling to mark up the flow rate and yield overall water recovery of 70-80%. Recovery rate must be design according to the inlet salinity and Silt density ie. from sea water then the overall recovery will be only 10% for the whole unit while 70-80% recovery can be produce from average ground water. I believe the statement that the disadvantage on small water recovery of 15% for household membrane may not be accurate. It could obtain a lot more information especially on design criteria from membrane maker.
Addition to note on RO design 2: If there is anything disadvantage on RO I would say the maintenance cost. For Ion exchanger the running cost is direct varies with water quality and less maintenance cost but for RO the running cost is low but with high maintenance cost. At high productivity of demin water the RO show advantage but if it is low productivity then the Ion exchanger become more favorable.
Addition to note on RO design 3: Regard waste water... It can't state that waste water from RO is actually more than Ion exchanger because the waste water from RO can easily pass as municipal waste water but for DI, it had high TDS and require neutralization and dilution which make overall waste water in similar figure. —Preceding unsigned comment added by 203.147.18.37 ( talk) 02:03, 8 October 2009 (UTC)
I can't find any information on the types of membrane materials typically used, neither directly in the article nor through links. This is a very significant deficit since they are the essence of the the technology! — Preceding unsigned comment added by 150.227.15.253 ( talk) 09:20, 25 May 2011 (UTC)
Based on size of pores, particles that can and can not pass through can be discussed here. Ashishfa ( talk) 14:24, 26 February 2016 (UTC)
![]() | This edit request by an editor with a conflict of interest was declined. |
Hello everyone. As indicated above, I have a conflict of interest for this article. I work for the company Desalitech, which is paying me to request that Wikipedia's reverse osmosis page be updated to mention our technology among the new developments. It's my honest belief that the article will be stronger if it acknowledges the unique reverse osmosis configuration being commercialized by Desalitech. I think it makes the most sense to mention it in the existing New Developments section. However, I am hoping that an experienced Wikipedian will work with me to ensure that so my suggestions do not violate Wikipedia's principles. Thank you in advance to any Wikipedians for taking the time to work with me. Vezina H2O ( talk) 20:48, 7 November 2017 (UTC)
I suggest adding the following sentence to the end of the article.
In 2016, the Global Water Award for Breakthrough Water Technology Company of the Year was awarded to the creators of the proprietary Closed Circuit Desalination (a.k.a. Closed Circuit Reverse Osmosis) reverse osmosis configuration, Desalitech. The rationale for the award was excitement at the 2015 International Desalination Association World Congress over the potential for Closed Circuit Desalination to provide a practical solution to the build-up of salinity in aquifers and waterways. [1]
The "Salt Ions" (as the sodium and chlorine ions are referred to in this article) have diameters on the order of 2.40 and 3.40 pm, respectively (diameters, not radii). The water molecule itself has a diameter of about 1.5 Angstroms, smaller than the diameter of either of the ions that are being "filtered out." I do not understand the mechanism well enough to explain it to you or rewrite the article, but it is clear from their relative sizes (as given by wikipedia) that filtration is not at work in the macroscopic sense, and that this is not made abundantly clear in the article (which it should be.) See also "RO Models and Structure," Below Juneappal ( talk) 06:47, 9 February 2009 (UTC)
Until I read the entry, I was sure that RO was just a marketing term for filtration. It sounds better to say that the water is RO vs. just filtered. Does filtration not apply to removal of solute? Is RO a subset, superset, or alternative compared to filtration? Thanks!
I understand that Fluoride is a very small molecule that can cross the blood brain barrier and so doubt that the RO membrane will stop it from passing and I would like someone to address with greater knowledge than I. There are RO systems advertising that they remove fluoride but I am skeptical.
Fluoride, an industrial waste from the Aluminum and Fertilizer industry is added to municipal waters for tooth decay prevention and there it great objections to this process of medicating the public with a non FDA approved medication.
Many compensate by buying RO water or, better, distilled water for drinking which is certainly free of this chemical. Tampasailor ( talk) 22:59, 31 August 2019 (UTC)
I was looking at this page for some more reading material and it looks like someone named "WaterScienceProf" has added (what I assume is) their own citations in various articles about this topic. (E.g., currently the first citation on the page.) I'm not sure what should be done about this, but it's definitely annoying for someone trying to learn the material. kuzutsu ( talk) 20:22, 7 August 2018 (UTC)
hi hoppp=[iho — Preceding unsigned comment added by 219.89.228.73 ( talk) 23:45, 1 May 2020 (UTC)
I am not a biologist, can anyone give a good description of what Reverse Osmosis is on the top of the article? it also needs to be wikified.. -- Rotem Dan 10:40 Apr 14, 2003 (UTC)
its a pity when they cant speak plain english eh? what it says is the membrane works like a sieve... its really just like any filter but it is a sheet with tiny holes in it that only allow the water to pass through... i think people need to make it sound complicated to try to justify the money the industry is making off of it... i pay $1 a gallon for it... gas is about $2 milk $2... so i guess like i said they want to make it sound like high tech water so they can justify making you pay for it.. or what ever — Preceding unsigned comment added by Majorheadrush ( talk • contribs) 21:22, 19 March 2017 (UTC)
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page doesn't exist Geoffreyiy1 ( talk) 08:47, 6 April 2021 (UTC)
This article was the subject of a Wiki Education Foundation-supported course assignment, between 19 January 2021 and 6 May 2021. Further details are available
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Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT ( talk) 08:06, 17 January 2022 (UTC)
It seems that an older theory (described here on Wikipedia) was recently proven incorrect. Jarble ( talk) 05:42, 9 May 2023 (UTC)
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