reverse osmosis


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reverse osmosis
reverse osmosis
reverse osmosis
reverse osmosis
Reverse Osmosis Systems
reverse osmosis
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Reverse Osmosis Connector Systems
reverse osmosis

reverse osmosis

Water Treatment by
Filtration, Conditioners, Distillation,
Deionization, And Reverse Osmosis.
By David F. Walling

 

Your city water department has a growing population of people to serve and most do a fine job of treating the water, (making it sanitary to drink). Some of the smaller water treatment plants in this country however have problem water to begin with and are out of compliance with the federal drinking water standards. If you believe that you live in an area with unsafe drinking water I recommend that you have an independent water analysis done by a company that is not going to try to sell you something after the test is done. Remember an independent laboratory makes money on doing the water tests not on the sale of water treatment equipment and they usually do not make recommendations. Once you have your lab results then you can shop around for the best method of treatment for your particular water problem.

Most tap water has aesthetic problems bad tastes, smelly, or cloudy water. This problem usually is the result of the distribution systems effect on the water after it is treated. A good example of this is to take a brand new 50-foot vinyl garden hose and drink the first 8 ounces that comes out of it. Taste pretty bad right, you have to remember that the pipes that carry the tap your water to your house is buried in the ground and can be miles long and some are very old. Contamination can come from old pipes that extend through a piece of ground that has been contaminated. There are chemicals that can penetrate the walls of pipe and contaminate the water flowing inside. This is not the only way that contamination can take place and it is a chemical form of contamination you can also have bacterial contamination but it is kept mostly under control in the presence of chlorine.

Filtration systems can remove particles down to a size of about .5 microns. If your tap water has sediment present then you will have to start with a higher micron rating and then filter down in stages 30, 10, .5 so that your final stage fine filter is protected from the larger particles that will fowl the .5 micron stage. Just for reference a human hair is about 10 microns thick. Ceramic filters can actually filter out bacteria and viruses but need to be protected from sediment. .5 micron rated filters can remove the relatively large coliform bacteria, e-coli, giardia cysts but has no effect on inorganic Total Dissolved Solids (TDS). These filters by themselves have little effect on bad taste unless they are accompanied by granular activated carbon (GAC). This media acts like a parking lot for organic contaminants but just like a parking lot when full, are no longer usable so they must be changed regularly. You should also consider sediment will greatly effect the ability of GAC to trap organic material. GAC filters rely on contact time with the water so the incoming water cannot flow to fast through the carbon bed a slower flow rate is preferred.

Water conditioners also have no effect on TDS. Conditioning works by trading soft sodium or potassium ions for the harder calcium carbonate or magnesium ions. To regenerate the resin in the treatment tank an ion exchange takes place in the treatment tank an eye for an eye in this case ion for an ion excuse the pun I couldn’t resist. This effect on the water is permanent and is considered in the water treatment industry as the most effective way to get hardness out of the water. One draw back is the added presence of sodium in the softened water. Many doctors warn their patients of the health risks of to much sodium in your diet. Water conditioners do not have any other effect on the water other than a "softening" effect, (the removal of calcium carbonate). These systems can be modified to treat iron and hydrogen sulfide, but the resins in the treatment tank must be modified. High TDS levels in the incoming water can greatly reduce the effectiveness of a water conditioners ability to condition the water. Tap water with TDS levels higher than 1500 parts per million will fowl the resin in your treatment tank. You will have to weigh the benefit of treating your water with a softener if your tap water falls into this category.

The EPA considers water containing more than 500 parts per million of TDS to be unhealthy for drinking water. There are three ways to reduce TDS levels in water. First you have distillation which vaporizes the water into a gas and then recondenses it into pure water. This method uses electricity to heat the untreated water to a boiling temperature therefore the system must be placed in a location with an electrical outlet nearby. Water is stored in an unpresurized storage tank witch flows by gravity to the faucet. This method of storing the water can allow your treated water to be recontaminated by airborne contaminants. Some organic contaminates have a boiling temperature that is less than that of water so they will end up in your condensing chamber as well, unless your distiller has a carbon filter to remove organics before the water enters the boiling chamber. It is impractical to represurize the water in the holding tank so it can flow to other appliances such as icemakers or instant hot water heaters. This is a major problem for distillers, although they can produce very high quality water.

Dionization (DI) is also very effective at reducing TDS but is generally used in commercial applications because the resin contained in the treatment tanks is considered hazardous and needs to be regenerated by professionals that can dispose of the toxic chemicals used to regenerate the resin. The size of the treatment tanks is determined by the amount of DI water needed therefore space must be a consideration when placing a system. DI is generally used to produce water that is not intended for drinking because bacteria can colonize in the treatment tanks at an alarming rate.

That brings us to Reverse Osmosis (RO) by far the most popular of the three there are many benefits in using RO over the other methods. It is a clean system no toxic materials are needed to service the RO system the only by-product of the process is water that can be used for other purposes. Water is forced through a semi permeable membrane very similar to cellophane food rap. In most residential applications no electricity is needed. Residential RO systems can reduce all waterborne contaminants organic and inorganic far below the recommended levels. RO systems compared to a normal filters micron rating are in the .001 micron range. This enables sea-going ships to use RO for desalinization (seawater purification) it is also the way that most kidney dialysis clinics treat city water for patient use. For the money spent on a water treatment system, consumers get the biggest bang for their buck. More contaminants removed for the money with RO than any other treatment method. One draw back of RO can be servicing the system this must be done on a regular basis like every 6 to 12 months or sooner depending on the quality of your tap water and the style of membrane used. The RO systems product water quality will be directly effected by the quality of the systems service. If service of an RO system is left unattended, then their can be total failure of the system witch can result in contamination of the product water. You will be drinking tap water. Like any other hi-tech gadgetry service is the name of the game. Sometimes just getting the RO system out from under the sink can be harder than the actual service of the system. I recommend using a quick connect manifold system so that all of the RO systems primary connections feed line, product line, drain line are located in the front of the undersink cabinet so that any time the system needs attention or in case of a plumbing problem the RO system can be easily turned off or removed by the homeowner or service person. The icemaker by-pass valve can also be incorporated into this manifold.

Most of the water treatment plants in this country have the ability to deliver potable water. The burden of making the water pleasant to drink is not in the hands of the water treatment facility. We have to remember that water treatment systems are built and maintained by people, and this unfortunately can lead to human error. An in home water treatment system or point-of-use equipment can act as a safety net in times that the water quality is in question but it must be maintained and not relied on with blind faith. These systems are only as good as the people that maintain them.

For more information, please contact R/O CONN at (602) 432-5402 or fax (602) 942-1451. Or you can E-mail us at roinfo@roconn.com.

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