| Reverse osmosis is a separation process used in | | | | great job in cleaning up brackish water, or hard |
| everything from the food processing industry, to | | | | water, i.e., water with excessive minerals such as |
| concentrate fruit juices, to water filtration and | | | | calcium, iron, lead, magnesium, sulfates, etc. |
| dialysis, where it is used to remove contaminants. In | | | | Disadvantages include the fact they remove all |
| this article we will discuss reverse osmosis, and | | | | minerals, even the trace minerals our bodies need, |
| osmosis, in order to answer the question, "What | | | | and water without minerals is slightly acidic and stale |
| does reverse osmosis do," by following the process | | | | or flat tasting. |
| as it filters pollutants from drinking water. | | | | Also, since cancer seems to thrive in an acidic |
| To answer the question, "What is reverse osmosis?", | | | | environment, many doctors advise against drinking |
| we need first to look at osmosis. | | | | de-mineralized water. Anyone using one of these |
| Let's say you have a container with two | | | | systems might want to look into taking mineral |
| compartments, separated by a very fine screen, and | | | | supplements. |
| there is pure water on one side of the screen and | | | | Another disadvantage is they do not remove |
| salt water on the other side. The screen is so fine | | | | pollutants having a molecular size smaller than water. |
| the salt molecules cannot pass through it, but the | | | | If there is chlorine in your water, for example, it will |
| water molecules can. If normal osmosis takes place, | | | | not be removed by reverse osmosis because its |
| the salt water concentration will slowly become | | | | molecules are too small. All of the carcinogenic |
| diluted by the fresh water. | | | | by-products of chlorine, and many synthetic organic |
| In reverse osmosis, pressure is applied to the salt | | | | chemicals, will not be removed either. |
| water side, forcing the water out, but leaving the salt | | | | The EPA recommends activated charcoal filters to |
| molecules behind the filter. Since the process is going | | | | remove such contaminants and one should definitely |
| against the normal inclination of the water, it is | | | | be used in combination with a reverse osmosis |
| referred to as reverse osmosis. | | | | system. |
| In the case of reverse osmosis used in filtering | | | | Even if the water is not chlorinated, a carbon |
| water, the screen is called a semi-permeable | | | | pre-filter is recommended to remove any volatile |
| membrane. The membrane is about as thick as a | | | | organic chemicals for health reasons and to protect |
| piece of cellophane with pores so small only particles | | | | the membrane. |
| the size of a water molecule, or smaller, can pass | | | | So, there you have it. A short explanation of what |
| through. | | | | reverse osmosis is, how it works, and what it |
| As the water squeezes through, contaminants are | | | | removes. |
| left behind to be flushed from the system. To speed | | | | The Good: As you have seen, reverse osmosis |
| up the process, it may be necessary to increase the | | | | systems will do wonders in cleaning up brackish water |
| amount of water pressure by adding a booster pump | | | | and water with excessive mineral content and, when |
| to the water line. Even with adequate pressure, | | | | used in combination with a carbon filter, delivers very |
| however, an appreciable amount of water will still not | | | | clean water. |
| pass through the membrane and will be lost as | | | | The Bad: The process is also bulky, prone to |
| waste. | | | | maintenance issues, is more expensive than other |
| Reverse osmosis systems are very slow producers | | | | filtering technology and delivers a "flat" tasting |
| and, in order to have enough clean water for bathing | | | | product some have deemed unhealthy for long term |
| and doing laundry, a storage tank (with a diaphragm | | | | consumption. |
| to maintain pressure) is needed. | | | | For information on Consumer Reports' top rated filter |
| One advantage of these systems is that they do a | | | | system, see my website below. |