I think your getting Osmosis process confused with revers Osmosis. RO is good for you as it takes everything out you get enough calcium and other needed minerals through your healthy diet.
Milk, vegtables etc..
here is a link with FAQ about RO systems
RO FAQ
Drinking water is never pure. Water naturally contains minerals and microorganisms from the rocks, soil and air with which it comes in contact. Human activities can add many more substances to water. But drinking water does not need to be pure to be safe. In fact, some dissolved minerals in water can be beneficial to health. For example, the National Research Council (National Academy of Sciences) states that drinking water containing dissolved calcium and magnesium generally contributes a small amount toward calcium and magnesium human dietary needs. Fluoride, either naturally occurring or added to the water supply, can help protect against tooth decay. Whether or not drinking water is safe will depend on which impurities are present and in what amounts
To understand "reverse osmosis," it is probably best to start with normal osmosis. According to Merriam-Webster's Collegiate Dictionary, osmosis is the "movement of a solvent through a semipermeable membrane (as of a living cell) into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane." That's a mouthful. To understand what it means, this picture is helpful:
On the left is a beaker filled with water, and a tube has been half-submerged in the water. As you would expect, the water level in the tube is the same as the water level in the beaker. In the middle figure, the end of the tube has been sealed with a "semipermeable membrane" and the tube has been half-filled with a salty solution and submerged. Initially, the level of the salt solution and the water are equal, but over time, something unexpected happens -- the water in the tube actually rises. The rise is attributed to "osmotic pressure."
A semipermeable membrane is a membrane that will pass some atoms or molecules but not others. Saran wrap is a membrane, but it is impermeable to almost everything we commonly throw at it. The best common example of a semipermeable membrane would be the lining of your intestines, or a cell wall. Gore-tex is another common semipermeable membrane. Gore-tex fabric contains an extremely thin plastic film into which billions of small pores have been cut. The pores are big enough to let water vapor through, but small enough to prevent liquid water from passing.
In the figure above, the membrane allows passage of water molecules but not salt molecules. One way to understand osmotic pressure would be to think of the water molecules on both sides of the membrane. They are in constant Brownian motion. On the salty side, some of the pores get plugged with salt atoms, but on the pure-water side that does not happen. Therefore, more water passes from the pure-water side to the salty side, as there are more pores on the pure-water side for the water molecules to pass through. The water on the salty side rises until one of two things occurs:
The salt concentration becomes the same on both sides of the membrane (which isn't going to happen in this case since there is pure water on one side and salty water on the other).
The water pressure rises as the height of the column of salty water rises, until it is equal to the osmotic pressure. At that point, osmosis will stop.
Osmosis, by the way, is why drinking salty water (like ocean water) will kill you. When you put salty water in your stomach, osmotic pressure begins drawing water out of your body to try to dilute the salt in your stomach. Eventually, you dehydrate and die.
In reverse osmosis, the idea is to use the membrane to act like an extremely fine filter to create drinkable water from salty (or otherwise contaminated) water. The salty water is put on one side of the membrane and pressure is applied to stop, and then reverse, the osmotic process. It generally takes a lot of pressure and is fairly slow, but it works.
Reverse osmosis (RO) is used to reduce dissolved solids from feed waters with salinities up to 45,000 ppm TDS (total dissolved solids).
Municipalities and industrial facilities are able to use RO permeate as a consistently pure drinking water supply and to transform drinking water to high purity water for industrial use at microelectronics, food and beverage, power, and pharmaceutical facilities. The technology is also very effective at removing bacteria, pyrogens, and organic contaminants.
Reverse osmosis separation technology is used to remove dissolved impurities from water through the use of a semi-permeable membrane. RO involves the reversal of flow through a membrane from a high salinity, or concentrated, solution to the high purity, or "permeate", stream on the opposite side of the membrane. Pressure is used as the driving force for the separation. The applied pressure (P) must be in excess of the osmotic pressure of the dissolved contaminants to allow flow across the membrane.
GE Water & Process Technologies uses spiral wound membranes - tightly packed filter material sandwiched between mesh spacers and wrapped in a small-diameter tube - to desalt and demineralize process water. The membrane's operating conditions are fine-tuned to balance the flux, or the amount of water which passes through the membrane, with the specific rejection rates of contaminants to achieve up to 99.8% salt rejection at low pressures and high flux rates.
A one-stop source for platforms that serve your water purification needs
Reverse Osmosis systems from GE deliver high performance at the lowest life-cycle costs. Our pre-engineered systems are built with high-quality components designed specifically for water purification. They arrive at your facility ready to run with all filters, membranes, pumps, piping, controls and automation.
GE spiral-wound membranes are cost-effective thin-film elements used to remove salts and separate organic material, by molecular weight or particle charge. Our products cover a broad range of applications, including:
Desalination
Food/beverage process separations
Industrial process separations
Water equipment primary components
GE supports you with a wide range of RO system components:
Autotrol multi-port valves for sand filters, activated carbon filters and water softeners.
Tonkaflo Pumps, Sanitary stainless steel membrane housings
Sievers 400 ES Pharma and 900 Series TOC analyzers
Aquamatic valves
E-Series ozone disinfection systems
/www.allaboutwater.org/reverse-osmosis.html
