With today’s concerns over contaminants in household drinking water, a reverse osmosis water filter is a popular choice for many health conscious families. Not only do these filters take out substances that make your water taste and smell bad, they also can remove other contaminants that are a real threat to your health.
How do reverse osmosis water filters work?
The RO unit contains a water storage container, reverse osmosis membrane, particle filters, carbon filter, and treated tap-water.
The RO membrane is the focal point of a reverse osmosis system, but an RO system also includes other types of filtration, most of them are made up of 3, 4, or 5 stages of it.
Most of RO system uses a three-pronged filter system: a prefilter, a semipermeable membrane filter, and a postfilter.
These three filters work together to remove sediment, chemicals, and contaminants, ensuring the water you use is as clean as possible.
Each type of system contains one or more of the following filters:
- Sediment filter: Reduces particles like dirt, dust, and rust
- Carbon filter: Reduces volatile organic compounds (VOCs), chlorine, and other contaminants that give water a bad taste or odor
- Semi-permeable membrane: Removes up to 98% of total dissolved solids (TDS)
- Prefiltration typically includes a carbon filter and a sediment filter to remove sediment and chlorine that could clog or damage the RO membrane.
- Next, water goes through the reverse osmosis membrane where dissolved particles, even too small to be seen with an electron microscope, are removed.
- After filtration, water flows to the storage tank, where it is held until needed. A reverse osmosis system continues to filter water until the storage tank is full and then shuts off.
Once you turn on your drinking water faucet, water comes out of the storage tank through another postfilter to polish drinking water before it gets to your faucet.
How Does a Membrane Separate Substances?
Reverse osmosis, or hyperfiltration water filter uses extreme water pressure that moves the water through a semipermeable membrane with microscopic holes separate out any contaminant or additives, its tiny enough for a molecule of water to pass through but too small for anything larger.
Most of the actual technology uses a process known as cross flow to allow the membrane to continually clean itself. As the purified water passes through the membrane the rest continues downstream, cleaning the membrane.
The RO filter is capable of removing particles as small as individual ions and dissolved organic molecules from water, like some bacteria, salts, sugars, proteins, particles, dyes, and other contaminants, depending upon the type of membrane utilized and the level of water pressure within the system.
Every reverse osmosis water system contains a sediment filter and a carbon filter in addition to the RO membrane. The filters are called either prefilters or post filters depending on whether water passes through them before or after it passes through the membrane.
Why does reverse osmosis water taste different?
The only reason that water has any flavor is because of the minerals that are contained in it. Different minerals and combinations of minerals are why we find that water will taste different from one area to another.
- the sodium in the water that causes it to taste salty,
- magnesium that will give water a bitter taste
- and calcium which gives water a milky type taste
- Sulfur-rich water will have a rotten egg smell to it which makes most people forget the taste of the water because the smell is more prominent
Even the best reverse osmosis drinking water systems will not necessarily remove everything in the water that can give it some kind of taste.
Reverse osmosis drinking water systems will also remove most odors that may have been in the untreated water. Because our sense of smell greatly contributes to how we perceive taste and flavors in the things that we eat, the lack of odor in the water can make the water seem to taste even cleaner.
Reverse osmosis (RO) is so far the best way to improve the taste of your drinking water. It reduces the amount of chlorine, total dissolved solids, and organic and inorganic substances present in the water you get from your tap.A curiosity about pure water is that coffee and tea drinkers love reverse osmosis water because it allows the true flavor of the coffee or tea to come through without the salty or bitter tastes that can be in untreated water.
Why is reverse osmosis water bad for you?
By using a reverse osmosis drinking water system, you will be able to remove minerals and extra sodium that you do not want , even minerals in water are important for health, avoiding chemicals, bacteria and contamination is also very beneficial too.
Minerals are essential to our cellular metabolism, growth, and vitality, and we can get majority of them from eating food like fruits and vegetables, grains and nuts.
The solution isn’t to avoid reverse osmosis but instead adding minerals to the water.
Benefits of Reverse Osmosis Water Filtration
- One of the most apparent benefits of reverse osmosis water filtration is that it provides clean, refreshing and pure water directly from your kitchen sink, your water becomes safer and healthier to drink and cook with.
- Reverse osmosis technology filters out these chemicals and toxins commonly found in tap water:
- VOCs (volatile organic compounds)
- PFOS & PFAS (perfluorooctanesulfonic & perfluorooctanoic acid)
- Reverse osmosis systems remove these contaminants and many others to eliminate unpleasant tastes and odors from your water.
- Reverse osmosis systems are also cheaper and more environmentally friendly than bottled water.
- It can easily be installed under your kitchen sink, in a utility closet, or another convenient location.
What are the disadvantages of RO water?
The rate at which a reverse osmosis system is able to create drinking water is very slow. Because of this lack of production, a storage tank is utilized, so that the system can filter the water and store it for future use.
These tanks pose several challenges, after the chlorine has been removed from the water by the filtering process, the water is pumped into the storage tank, where it mixes with old water until it is needed.
This warm, dark tank is exactly the right environment for bacteria, viruses, algae, and other life forms to breed and multiply.
- A standard R.O. system wastes nearly five times as much water as it creates – with a system operating at 35 gallons per day wasting around 5 times that much.For this reason, it is typically not practical to use reverse osmosis as a whole house filtration system. Usually they are purchased as a unit that sits under the sink and treat only the drinking and cooking water.
- Many reverse osmosis systems remove the good with the bad. Iron, calcium, manganese, and fluoride are a few of the beneficial chemicals that may be removed, depending on your system fluoride is a substance used to prevent cavities.
- A reverse osmosis filter will usually be used with a carbon or some other type of mechanical filter which will remove dirt and sediment and keep the fine membrane from clogging. But as with any type of filter, the longer it is used, the more clogged it gets, and the less effective it will be; so the reverse osmosis filter must be changed periodically.
- Bacterial Contamination
- There can be defects in the membranes allowing the viruses or bacterias to pass through.
- Secondary contamination, where bacteria will move up the pure water stream and attach to the membrane.
- As some water filters remove biocides (substances that can control the growth of harmful organisms, such as chlorine), it is possible that bacteria will re-grow unless the filtered water is stored in a sterile container in a cool, dark place.
- Some water filters may also allow bacteria to multiply to great levels on the filter pads if they are not maintained regularly.
Can reverse osmosis remove bacteria?
Bacteria will be removed via reverse osmosis due to size exclusion.
The bacteria are larger than the pores in the reverse osmosis membrane so they can’t pass through.
But as we said before, even thought bacteria can be removed via reverse osmosis, these systems are rarely certified to be microbiological purifiers.
So what do I do if I already own an R.O. system?
- Before buying one, make certain your system has an automatic shut-off valve so that it does not continue wasting water even when the tank is full.
- Consider installing a Water Safe Pro UV Chamber only between the tank and your faucet. This allows you to utilize your current system while avoiding any possible microorganism exposure from your holding tank or which has passed through the membrane .
- Finally, if your source water Does Not contain harmful dissolved solids, consider the annual cost of maintaining your RO system combined with the amount you would save with a reduced water bill against the price of a Water Safe Pro UV system.
- Careful consideration should therefore be given to the quantity of water required, and the time it takes to filter, before you buy a water filter. Usually, water filters with a faster water flow are more expensive.