While local water supplies are usually treated to reduce the presence of contaminants, such as bacteria, lead, mercury and pollutants there is a room to improve water quality. First, these contaminants can sometimes enter water through accidents or through the improper disposal of certain materials. Second, certain chemicals are intentionally added to warter, for example for desinfection, such as chlorine.
In order to make sure you're well-protected from these, water purification is a must. The purification process helps remove contaminants that might have entered your drinking water. Here are some of the top reasons as to why you need water purification.
Chemicals and other toxic materials from agricultural fields, industrial exhausts, automobiles, landfills and other sources of pollution of modern world can make their way into water sources, which increases the risk of getting some types of cancer. Eliminating these through water purification might help lower your risk of getting cancer that is associated with exposure to these chemicals.
Some contaminants do more than pose a health risk. They can also affect the flavor of drinking water, such as giving it a metallic taste or another unpleasant taste. Purifying water helps get rid of these contaminants, which can improve the flavor of drinking water.
Chlorine in drinking water is known to cause a wide range of serious health issues. These include the following:
Using water purification systems helps get rid of chlorine in drinking water, which reduces your risk of these health problems. This helps keep you and your family safe from illnesses and can improve your overall quality of life.
Boiling water before using it helps remove some contaminants (not all!), but this is also a time and energy-consuming process, especially when larger amounts of water are needed. Water purification systems offer a convenient way to get rid of contaminants while also saving time.
Regular bottled water purchases obviously require either hiring a service provider or making an extra effort to carry heavy bottles from your grocery store.
Pipes and plumbing system can introduce copper and other contaminants into your water supply. Even though your local water supply is treated, these contaminants are able to enter your home as water flows through old, corroded pipes. Purifying your water helps keep these materials out of your drinking water.
E.coli and other bacteria can cause serious illnesses when you're exposed to them in your drinking water. While some of these bacteria might cause mild symptoms, such as nausea, others can be life-threatening, especially in children, older adults and those with conditions that lower their immunity. A water purification system helps ensure that your drinking water is free of these potentially dangerous types of bacteria.
Purchasing bottled water usually provides your household with water that does not contain contaminants, but the cost of buying these bottles can add up significantly over time. Investing in a water purification system leads to a lower amount of money spent on having clean water. This can add up to considerable cost savings in the long run.
While bottled water looks a good way of getting safe water please remember that plastic bottles may contain a compound named BPA, or bisphenol A, which is often found in disposable water bottles. Small amounts of it can dissolve into the water inside these containers. A host of studies have shown that BPA can mimic the actions of oestrogen, a human hormone which is normally involved in breast development, regulating periods and maintaining pregnancies. Animals exposed to BPA develop abnormal reproductive systems, and there are indications that same may be applicable to humans.
Using a water purification system can reduce your carbon footprint and help protect the environment. Having purified water available in your home at all times means you don't have to use plastic water bottles, which harm the environment as they sit in landfills. You're also helping by reducing the need for bottled water that contributes to environmental damage through carbon emissions as it's transported from one place to another.
Water purification systems do more for you than just provide you with drinking water that does not have contaminants. It also gives you a steady supply of purified water that can be used for other purposes, such as rinsing off vegetables, preparing meals, brewing coffee or tea, and even making ice cubes. This can help your foods and beverages taste fresher and provide you with peace of mind that what you eat and drink is free of potentially harmful contaminants.
Water purification doesn't just benefit you. It also benefits your pets and plants. Using purified water when you fill your pets' water bowls helps lower their risk of exposure to pollutants that might affect their health. Watering your plants with purified supplies of water also helps reduce their risk of being harmed by certain kinds of chemicals that can enter your water supply.
Reverse osmosis (R.O.) is a water purification technology that uses a semipermeable membrane to remove ions, molecules and larger particles from drinking water. Reverse osmosis can remove many types of dissolved and suspended species from water, including bacteria, and is used in both industrial processes and the production of potable water.
In reverse osmosis, an applied pressure is used to overcome osmotic pressure. The result is that the solute is retained on the pressurized side of the membrane and finally goes down the drain, and the pure solvent (water) is allowed to pass to the other side.
In the normal osmosis process, the solvent naturally moves from an area of low solute concentration, through a membrane, to an area of high solute concentration. Applying an external pressure to reverse the natural flow of pure solvent, thus, is reverse osmosis.
There are several widely used technologies and types of filters for home or office use. Without going much into detail a few can be named:
Reverse osmosis systems are the most advanced water filtration machines because:
Most conventional reverse osmosis systems must use water storage tank as a buffer water container. They need the tank because they are usually equipped with tiny R.O. membranes typically of 50 gallons per day production rating, and often even without a pump. Such low production setup is not capable of producing pure water in real time with acceptable flux. Instead, such systems slowly accumulate produced clean water in the storage tank and deliver it from there when you turn on the faucet.
On the contrary, a direct flow R.O. system is capable to produce acceptable water flux directly, in real time, immediately after the faucet is open, mainly thanks to the large high production membrane and much higher pressure developed by powerful pump. Such systems don't need intermediate water storage tank, and also have multiple other benefits.
Major Benefits of the Direct Flow R.O. Systems:
It is water purified by reverse osmosis membrane. It is free from most contaminants including dissolved solids, metal ions, bacteria and viruses but usually contains natural air gases from atmosphere such as oxigen and nitrogen.
Permeate can be further processed by post-filters for conditioning, thus becoming finally the drinking water of highest quality.
It is water that did not pass through the reverse osmosis membrane. It contains high concentration of contaminants that were rejected by the membrane. Usually, this waste water goes down the drain. Never use concentrate for drinking or cooking.
Total dissolved solids (TDS) is a measure of the combined content of all inorganic and organic substances contained in a liquid in molecular, ionized or micro-granular (colloidal sol) suspended form. Reverse osmosis membrane reduces TDS significantly, thus making water pure and safe.
TDS is often measured by a conductivity meter in ppm (parts per million). In such a method, contaminants concentration (ppm) is calculated from electrical conductivity based on calibration on model solutions.
TDS level measured by conductivity meter is a good way to know how reverse osmosis membrane is performing. But this method doesn't normally work for other types of filters, escpecially with ion-exchange resins. This is due to the fact that electrical conductivity measrement is not sensitive to neutral chemicals, gases or suspended particles, including bacteria, in the water. Neither it may tell one type of ions from others, so it doesn't "see" the ion exchange occured. While filter may still perform exceptionally well and continue to produce pure water, conductivity meter may not be able to sense this. In other words, if measured TDS is reduced after the water filter then it is good, and is a direct indication that filter works. However, for filters without R.O. stage TDS is not informative, and measured TDS level may not decrease even if filter is performing well.
In simple words the R.O. membrane rejection rate is the percentage of contaminants the membrane removes, i.e. it shows how effective the RO membrane is removing contaminants.
Using TDS meter (conductivity meter), one may estimate the rejection rate as follows. If measured TDS of the source water, say, is 300ppm, and permeate TDS is 6ppm, then the rejection rate is (300-6)/300=98%. In R.O. filtration, contaminants to be removed by the membrane are routinely called salts. It's worth noting that such conductivity method takes into consideration all salts combined. Actual rejection rate is specific for each particular contaminant. In the example above salt passage is 2%, salt concentration drop is 50 times (from 300ppm to 6ppm), and salt rejection is 98%. If we'd measured permeate TDS to be 15ppm, then salt rejection would be 95%, and salt passage 5%. Here one can understand what a big difference is between rejection rate of 95% and 98%: it means 2.5 times difference in actual contaminants concentration remained in the water after filtration (15ppm vs 6ppm). The membrane with rejection rate of 98% is doing 2.5 times better job than the one with 95% rejection rate. Harmful contaminants concentration drops 50 times thanks to the former membrane, and only 20 times thanks to the latter.
Recovery rate is the amount of water that is being 'recovered' as good permeate water. Another way to think of recovery rate is the amount of water that is not sent to drain as concentrate, but rather collected as permeate or product water. The higher the recovery % means that you are sending less water to drain as concentrate and saving more permeate water.
For example, if the recovery rate is 25% then this means that for every 10 gallons of feed water that enter the R.O. system, you are recovering 2.5 gallons as usable permeate water and 7.5 gallons are going to drain as concentrate.
Sometimes more exact term is used: instant recovery rate which means the recovery rate of the membrane alone during R.O. process only, not taking into consideration waste of drainage water during service operations like flush, back-washing and the like, or saving more water by multi-stage reverse osmosis. To describe the recovery percentage of the system as a whole in typical operation conditions another term then used: efficiency rate.
Conventional R.O. systems with a tank recover only 5 to 20% of the water entering the system. On the contrary, direct flow R.O. systems may recover 50% and more of influent water, thus leading to several times less water waste and significant savings on costs and water resources.
Efficiency rating means the percentage of the influent water to the system that is available to the user as R.O. treated water under operating conditions that approximate typical daily usage.
Conventional R.O. systems with a tank recover only 5 to 20% of the water entering the system. On the contrary, direct flow R.O. systems, such as Expert MOD600, may recover 50% and more of influent water, thus leading to several times less water waste and significant savings on costs and water resources.