Osmosis is the phenomenon of water flow through a semi-permeable membrane that blocks the transport of salts or other solutes through it. Osmosis is a fundamental effect in all-biological systems. Osmosis is applied to water purification and other chemical laboratory and industrial processes. When two water volumes are separated by a semi-permeable membrane, water will flow from the side of low solute concentration to the side of high solute concentration. The flow may be stopped or even reversed by applying external pressure on the side of higher concentration. This is called reverse osmosis. (R.O.) Reverse osmosis is only one stage of a typical R.O. system. Sediment and carbon filtration is normally included with an R.O. system, with each stage of filtration contributing to the purification process.
The first stage of filtration is the sediment filter, which reduces suspended particles such as dirt, dust, and rust.
The second stage of filtration is the carbon filter, or filters which reduce volatile organic chemicals, chlorine, and other taste and odor causing compounds.
The heart of Reverse Osmosis is the membrane. It is responsible for rejecting up to 98% of the total dissolved solids in the water. This is where the purification takes place.
In the natural cycle of water, water that began its life as rain and eventually found its way to your tap has come in contact with many sources of potential contaminant. The various minerals and salts that have been dissolved by the water during this cycle are called Total Dissolved Solids (TDS).
Faucet-Mount and Pitcher filtration systems on the market are able to reduce certain contaminates from your water based upon the use of granular activated carbon, or in some cases carbon blocks. Some units include additional filter media that will reduce some heavy metals as well. These type of devices are limited to the types of contaminates that they can effectively reduce from your water based upon the type and amount of carbon contained within the filter.
The Express Water Reverse Osmosis (RO) incorporates three different types of filtration technology in order to provide the best quality water to the user. The first stage is a sediment filter which reduces larger particles and sediment from your water. The second and third stage with in our RO is our carbon block filter. Express Water uses only high quality independently certified carbon blocks. This additional certification on our carbon blocks ensures the consistency and integrity of the carbon block in each system we sell. These carbon blocks are able to reduce many contaminants with in your drinking water. The work horse of our system, the RO membrane, is next and is where the main filtration takes place to reduce any remaining contaminates or up to 97.9% of impurities in the water. The RO membrane is responsible for reducing many of the difficult water contaminants such as lead, arsenic, chromium, radium and total dissolved solids. The fifth and final stage is a granular activated carbon filter which polishes your drinking water just prior to you drinking it. The combination of these technologies, mainly with the use of the RO membrane, is how the RO system can provide to you water that is bottled water quality.
While a health claim can not be made because of intangibles such as regular maintenance, these items are too large to pass through the TFM membrane. NSF's rating for reduction of Giardia Cysts and Cryptosporidium is 1 micron, and the TFM membrane filters down to 1/10,000th of a micron. That is 10,000 times smaller than these parasites.
A CTA (Cellulose Triacetate) membrane is a paper by-product membrane bonded to a synthetic layer. Due to its cellulose composition, a CTA membrane requires chlorine in the water source to keep bacteria from forming on it. A CTA membrane has a rejection rate of between 85-94%. CTA membranes have an average life expectancy of 18-24 months and are considered inferior to TFM membranes. Express Water only uses TFM (Thin Film Membrane) membranes, which are made of a synthetic material. A TFM membrane requires the chlorine be removed prior to the water entering the membrane. A TFM membrane has a rejection percentage between 95-98%, which is much higher than the CTA membrane. A TFM membrane will last between 2-5 years. Many hospitals use TFM membranes in their hemo-dialysis (kidney) machines because of the higher purity water they produce.
They are washed down the drain. Unlike filters, the R.O. membrane is self-cleaning. As the source water flows through the module, it is divided into two streams. One stream is forced through the membrane by osmotic pressure created due to the water pressure on each side of the semi-permeable membrane. The second stream carries the rejected salts, dissolved pollutants and contaminates to the drain. Therefore, there is a minimum accumulation of debris on the pressure side of the membrane. Charcoal or carbon filters, on the other hand, become less efficient with each glass of water drawn through them. Carbon filters only remove a limited number of contaminants, some odors, and some tastes.
There is a certain percentage of water from the system that goes to the drain. This water is carrying away the impurities. These particles are too small to be caught by the filters. Express Water has an automatic shut-off valve that shuts off the flow of water to the drain when the holding tank is full. This valve stops the R.O. system from continuously running water down the drain, thus conserving water via the R.O. system working only according to usage.
Yes. Most wastewater today is recycled for golf courses and artificial lakes. The drain water is slightly higher in TDS concentration than the incoming water, but as R.O. does not add anything to the water, it can be used to water your lawn or garden.
It is the pressure of water that forces the water through the membrane for purification and flushes the rejected solids away. Low water pressure will result in reduced production and premature fouling of the membrane. The ideal pressure for operating an R.O. system is 60 PSI. Pressure below 40 PSI is generally considered insufficient, and should be boosted using a pressure booster pump.
Yes. Iron will plug a R.O. membrane, as the membrane is not able to flush iron out. Trace amounts of iron (up to 2 PPM) can be removed by a water softener. If the water contains 1 PPM or less, there is no need for concern as the membrane will usually last 1-2 years. Note: This refers to clear water iron, not red iron. The difference is that clear water iron leaves no visible signs, whereas red iron leaves a reddish brown discoloration in toilet bowls, tanks, sinks and tubs. If red iron is present, steps to remove the iron will have to be taken, otherwise the warranty will be void.
Yes. It is highly recommended. The Express Water R.O. system has been designed to operate best to give high quality quality water with normal routine maintenance. By changing the pre-filters on a regular six-month basis, you will eliminate dirt and chemicals in the water that will plug the membrane. After six months of use, the carbon filters can have bacteria growing within the filter media. Your local water conditions may necessitate more frequent filter changes.
This topic has been brought up due to a change in technology regarding the membrane and standard systems. Before the invention of the in-line flow restrictor there was an enclosed flow restrictor that could not be cleaned. This flow restrictor was enclosed in a solid plastic casing and had to be changed every time you changed the membrane. With our new in-line flow restrictor it can be removed, cleaned and reinstalled without having to purchase a new one. This new flow restrictor makes it even easier to maintain your RO system. The following diagram demonstrates the differences.
Yes. The 1st stage sediment filter must be a 5 Micron, 10" cartridge. The 2nd stage filter is more crucial. A purification grade carbon must be used, also 10" length. Express Water recommends the customer use Express Water's G.A.C. 56 cubic inch carbon filter because our filters have more carbon than others, therefore, better filtration. The system's various components are designed to enhance each other, thus the system will work much better. You can use other carbon filters; however, you may need to replace them more often due to their smaller volume of carbon.
The module part of the R.O. system measures: 15 ¾" Tall x 14" Wide x 5 ¼" Deep on the Model #4SV and 15 ¾" Tall x 16 ¼" Wide x 5 ¼" Deep on the Model #5SV. The storage tank measures: 11" Diameter x 16" Tall.
Due to R.O. water being void from contaminants, it is what is known as "hungry water." R.O. water can leach the minerals out of the copper tubing and may cause a metallic taste in the ice cubes and over a period of time, the copper tubing can develop pinhole leaks.
You will be able to tell by the taste and clarity of the water. For example, ice cubes made with the R.O. water are harder, clearer, and last much longer. If you take two clean glasses of the same size and put ice cubes made with R.O. water in one and the same number of ice cubes made from tap water in the other, you will notice that it takes longer for the R.O. ice cubes to melt. Not only do ice cubes made with R.O. water last longer but juices and mixed drinks made with R.O. water taste better. When ice cubes made from tap water are melted in a glass, you will most likely see unsightly sediments on the bottom. This is not so with R.O. water. Another way of determining the amount of dissolved solids removed from tap water is by the use of a conductivity meter. This meter measures the conductivity the dissolved solids impart to the water. This is converted on the meter scale into parts per million of Total Dissolved Solids (TDS). Express Water offers a water sample kit for the testing of a customer's water to determine how the TFM membrane is working and when to replace the membrane.
No. A water softener reduces hardness - or calcium and magnesium from the water and is usually installed at the point-of-entry (P.O.E.) of the water to the house. A water softener is good for the home's plumbing and water related appliances, but does little to improve the taste or quality of your drinking water.
No. Calcium and magnesium (lime scale) are two of the hardest minerals for the R.O. membrane to remove. Sodium (added to the water by the softener) is much easier on the membrane and it will reject 98% of all sodium in the water. A water softener will help extend the life of the membrane.
Yes. R.O. water is softened through the reverse osmosis purification process; however hard water (above 7 grains of hardness) will shorten the life of the membrane. The harder the water, the shorter the life. Example: If you incoming water is 15 grains hard, you may only get 2-3 years of life from your membrane.
Faucets have a light to notify you when your filters need to be changed. Watts Premier offers two types of notification faucets.
Faucets with a TDS meter, measure the TDS (Total Dissolved Solids) in the water. This is accomplished by monitoring incoming water vs. Reverse Osmosis water, if the RO water falls below a preset standard the light changes color to notify you to change your filters. This type of faucet has wired probes attached to the water lines for monitoring.
Faucets with a time calculation. When you change your filters and remove the battery on the faucet this resets the clock to 0 months. When you re-instert the battery the timer starts a new timed count to 6 months. When the count equals 6 months the light on the faucet will change colors.
Older faucets displayed a green and red light for notification. All 2011 and forward will display a blue and red light indicator for notification.
California's Proposition 65 entitles California consumers to special warnings for certain products that contain chemicals above certain threshold levels.
The general Proposition 65 notice is as follows: WARNING: This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.
Proposition 65 notice for wood products is as follows: WARNING: Drilling, sawing, sanding or machining wood products generates wood dust, a substance known to the State of California to cause cancer. Use a respirator or other safeguards to avoid inhaling wood dust.
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