| Reverse Osmosis-Great System If You Need One-But Do You? | | Print | |
| Written by David Eastham | ||||||
| Friday, 21 November 2008 | ||||||
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That's right, reverse osmosis water units are hard to beat when you have a problem like salt in your drinking water supply. But most of us don't have that problem; we get our water from a municipal supplier or from a chlorinated well. And, for those people, I've got good news indeed. You will get a better result from selective filtration systems than you ever could with reverse osmosis. In today's article we will examine both systems and how they differ. Then you can decide which one is best for your situation.
That's right, reverse osmosis water units are hard to beat when you have a problem like salt in your drinking water supply. But most of us don't have that problem; we get our water from a municipal supplier or from a chlorinated well. And, for those people, I've got good news indeed. You will get a better result from selective filtration systems than you ever could with reverse osmosis. In today's article we will examine both systems and how they differ. Then you can decide which one is best for your situation. The RO system works by forcing water against what is called a semi-permeable membrane. The membrane's pores are so tiny that any object larger than a molecule of water will not pass through it. Often, water molecules cannot get through either and, usually, this water is simply discarded along with any minerals or contaminants that have been screened. In general, these systems reject two or three gallons of water for every filtered gallon produced. Hard water or water with excessive minerals is a problem in many water supplies and the fact that RO systems remove these minerals is another plus for these systems. However, it also has been found to cause another problem. The fact is we need some minerals left in the water because our bodies need them. The second largest component in our body after water itself is calcium. If we constantly drink water with no minerals we are drinking water that is slightly acidic and it wants to return to its neutral state. One way for it to do that is to swipe some calcium from our cells, bones or teeth to produce calcium carbonate, a neutralizing compound. Medical professionals also tell us cancer cells appear to always grow in environments which are slightly acidic, so, they think there can be an increased cancer risk for people drinking mineral-free water. When it comes to synthetic organic chemicals (SOCs), they usually have a smaller molecular structure than water, and will pass right through the membrane. These are compounds like herbicides, pesticides, etc. In order to get the dirty SOCs out of the water, RO systems must be used in combination with a carbon filter. RO systems requires adequate water pressure to force the water against the membrane and, for some users, this may call for the addition of an inline booster pump. If you want to have more than just drinking water from an RO system you will need to add a storage tank, since these systems only filter a gallon or so of water per hour. In order to keep a constant pressure on the system a tank with a diaphragm is normally used. As you can see, these systems with their filters, storage tanks, and, perhaps, an additional pump are sizeable and, as you might imagine, they are relatively expensive, somewhat difficult to install and subject to extra operating and maintenance costs. For most of us, using an RO system where you could use selective filtration is like using a backhoe to get a little crabgrass out of your yard. Sure, it'll get the job done, but the ensuing pain won't be worth it. Selective filtration is also called multi-stage filtration and it is a good alternative to reverse osmosis. Carbon is also used in these systems to take out any chemicals and drugs present in the water, however, this carbon has been blended with a filter resin that is chemically charged and the whole thing is extruded into a solid carbon block containing very fine, micron sized pores. One cubic foot of this activated charcoal that has been so tightly compressed has the adsorption area of five square miles, according to scientists. The tiny pores filter out tiny, chlorine-resistant, cysts like Cryptosporidium and Guardia and the rest of the surface area scrubs up the chemicals and drugs. What about the filter resin that covers the surface of the adsorption area? As water passes across the resin, positively charged heavy mineral ions in the water, like lead or mercury, for example, are forced to break their bonds with water, and attach to the chemically charged resin like little magnets. Lighter minerals like calcium and potassium stay put. There you have it, the water is cleaned but it still has its nutritious trace minerals. Selective filtration systems are quick, so there is no need for holding tanks with diaphragms. Nor is there any need for booster pumps, electricity, backwashing, etc., and, if installed correctly, they operate virtually maintenance free. If you have a really gross water condition to remedy, it is always wise to talk to a technical representative for any filter system you are considering. These techs are great and they almost always have a solution. And, please note, selective filtration is not designed to treat brackish or salty water. Article Author: David Eastham has done exhaustive research on such topics as reverse osmosis to discover the most economical way to provide good, clean drinking water. Here are his picks as the best dollar for dollar buys, and the best products overall, in home water filtration systems.
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