What is the process for recycling drinking water?

Will Reverse Osmosis remove sodium and residue from softened water?

• OK I am, once again - bringing my question to "The Smart Ones" at Google Answers. HELP! We have recently moved to a high-rise condo building on Clearwater Beach that softens all the water (both hot and cold) that runs into each of the individual units. A reverse osmosis system has been installed under the kitchen sink for drinking water. Of course, the water going into this system is soft water. I have tried to find out if this type of a system really has the capacity to remove the sodium in the soft water. In fact, I have tried to find out if reverse osmosis is even effective. I have tried researching this but have found that only those trying to sell reverse osmosis say it works well to remove the sodium and other residue from the water softening process. This question will be answered if you can lead me to some articles addressing soft water and affective filter systems to remove the sodium and make the water healthy to drink. Is there a test strip or kit we can get to test our water for sodium levels? Also, if there is a better type system to clean softened water, some article references on this would be much appreciated. Perhaps softened water and sodium residue in drinking water is not even something to be concerned about. (I drink lots of water) Do any of you have any opinions on this?

• Answer:

  Hello again, Carolyn! A Google search on this subject turns up many sites that are selling something. I am always reluctant to rely on information acquired from a commercial site, so I did not include that kind of material in my research. Unfortunately, search engines are not yet smart enough to automatically eliminate commercial sites from search results, so this was a filtration process that relied upon my mind as a filter, rather than Google's estimable artificial intelligence. Come to think of it, that's what Google Answers is really designed for: to place a human mind into the search effort. I've found several articles that discuss reverse osmosis and sodium. For reasons of copyright, I am posting only brief excerpts below. You may want to read these articles in their entirety, since they contain quite a bit of information that may be of use to you. "A technique used in processes requiring high-quality, purified water, such in semiconductor processing or biochemical applications, is reverse osmosis. It can be used to treat boiler feedwater, industrial wastewater, or process water. Reverse Osmosis is a water purification technique that reduces the quantity of dissolved solids in solution... It is necessary to establish feedwater quality guidelines to optimize system performance and prevent the three main problems associated with RO: scaling, fouling, and degradation of RO membranes... Rensselaer Polytechnic Institute: Introduction to Reverse Osmosis http://www.rpi.edu/dept/chem-eng/Biotech-Environ/MISC/biotreat/reverseo.html "Reverse osmosis (RO) has become a common method for the treatment of household drinking water supplies. Effectiveness of RO units depends on initial levels of contamination and water pressure. RO treatment may be used to reduce the levels of: 1. Naturally occurring substances that cause water supplies to be unhealthy or unappealing (foul tastes, smells or colors). 2. Substances that have contaminated the water supply resulting in possible adverse health effects or decreased desirability. RO systems are typically used to reduce the levels of total dissolved solids and suspended matter. The principal uses of reverse osmosis in Minnesota and the Dakotas are for the reduction of high levels of nitrate, sulfate, sodium and total dissolved solids. RO units with carbon filters may also reduce the level of some SOCs (soluble organic compounds) like pesticides, dioxins and VOCs (volatile organic compounds like chloroform and petrochemicals). An RO unit alone may not be the best solution for these types of contaminants, but installing a properly design-ed RO unit to reduce the levels of other contaminants may provide a reduction in SOCs and VOCs." North Dakota State University: What impurities will reverse osmosis remove? http://www.ext.nodak.edu/extpubs/h2oqual/watsys/ae1047w.htm "Reverse osmosis (R/O) is a water treatment process in which water is forced through a semi-permeable membrane that has very small holes or 'pores'. Clean water passes through and impurities that are too big to pass through the membrane are left behind and flushed away... Reverse osmosis can remove dissolved solids, salts, minerals that cause hardness, organic chemicals and other impurities. It can improve the taste of water for people who do not like the taste of dissolved mineral solids. Treated water will not produce scale in kettles and coffee makers. Because sodium and potassium are removed, people on a medically prescribed sodium- or potassium-restricted diet may benefit. R/O units may also remove contaminants such as chromium, mercury and nitrates... R/O units will not operate efficiently at water pressures below 40-45 psi. If the pressure is too low, as in the case in many rural private systems; in an apartment on a higher floor of a building; or at the end of a long water line serving several units, a booster pump should be installed to increase pressure." Canada Mortgage and Housing Corporation: Reverse Osmosis - Water Treatment http://www.cmhc-schl.gc.ca/en/burema/gesein/abhose/abhose_068.cfm "Q. Is there a household water treatment device which will remove the potentially dangerous, health-related metal impurities from water for drinking and cooking? A. Yes. Several systems are small enough to be installed under a kitchen sink to supply a special faucet, ice cubers, etc., with highly purified water for cooking and drinking. These systems operate on well-known water purification principles, such as demineralization and reverse osmosis, and will substantially remove not only the metals, but laxative sulfates, sodium and other minerals from the water... If you suffer from hypertension or are on a sodium-restricted diet, you should consult your doctor about the proper water for drinking. Since most hard waters also contain sodium, your doctor may recommend that you drink sodium-free packaged or bottled water, or remove sodium from your water by demineralization or reverse osmosis." Canadian Water Quality Association: Soft Water and Your Health http://www.cwqa.com/html/consumer6.html "Will Reverse Osmosis remove sodium from water? Yes. The initial application of the reverse osmosis process was removal of salt (desalinization) from sea water for use as drinking water aboard naval vessels. This application has been expanded to include large, land-based facilities supporting entire communities. This may prove to be very beneficial to someone on a low sodium diet." The Whole Truth: Reverse Osmosis F.A.Q. http://www.thewholetruth.org/Res_WP_RO_FAQ.htm#9 In conclusion, reputable reference sources indicate that reverse osmosis will remove sodium and many other minerals from water. The main caveats are that the membrane and pre-filters must be kept in good condition, and that the water pressure must be kept above 40 pounds per square inch. The consumption of water is increased significantly by an RO unit, which may be a concern in areas where water is rationed, or is costly. Water purification is not my research specialty, but, in my layman's opinion, RO seems to have many more pluses than minuses. I would love to have a reverse osmosis unit for my household, and I fully intend to purchase one (as well as a water softening unit) when my budget permits it. Regarding the matter of testing your water, there are numerous labs that can do this for you. Here is a list of water testing laboratories in the Clearwater Beach area. Some of these firms have websites that can provide more info on the services that they offer: Superpages: Water Testing Laboratories, Clearwater Beach http://phonebook.superpages.com/yellowpages/C-Water+Testing+Laboratories/S-FL/T-Clearwater+Beach/ There are salt test strips which are designed for swimming pool owners, but they are only accurate at detecting rather large amounts of sodium (in the vicinity of 1000 ppm and up, which is VERY salty from the standpoint of drinking water - most tap water contains 100 ppm or less). I don't think test strips would be useful for your purposes. To be honest, unless you have reason to suspect the integrity of your RO membrane and/or filters, I doubt that testing is really necessary, since a reverse osmosis unit, if it is doing its job, can be counted upon to remove sodium from your water. Google search strategy: Google Web Search: "reverse osmosis" + "remove OR removes" + "sodium" ://www.google.com/search?hl=en&ie=UTF-8&q=%22reverse+osmosis%22+remove+OR+removes+sodium Google Web Search: "clearwater beach" + "water" + "testing" ://www.google.com/search?hl=en&ie=UTF-8&q=%22clearwater+beach%22+water+testing Google Web Search: "home" + "water test OR tests" + "sodium" ://www.google.com/search?hl=en&ie=UTF-8&q=home+%22water+test+OR+tests%22+sodium I hope this helps! If I'm off target, or if anything additional is needed, please let me know, and I'll get back to you as soon as I can. Best always, Pink