What are filters for water?
Water filters improve the quality of water by removing undesirable contaminants such germs, hardness, taste and odor, and sediment. We provide an extensive selection of filters and cartridges to address a wide variety of water-related problems, from creating better-tasting drinking water to more specialized uses like brewing coffee and creating crystal-clear ice.
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The Five Filter Types
There are five different kinds of water filters, depending on your application, or what you’re attempting to eliminate or, in certain cases, stop:
Filters that are mechanical
Filters for Absorption
Filters for Sequestration
Filters for Ion Exchange
Filters for Reverse Osmosis
Each of them tackles a distinct water issue, and many filters combine these techniques to carry out many filtration stages.
How Do They Operate?
One of the most significant materials on Earth is water, which makes up 71% of the planet’s surface and may make up up to 75% of the human body. Numerous industries, including agriculture, science, medicine, transportation, heating, recreation, food processing, washing, and—possibly most importantly—drinking, depend on water.
Most of us get our drinking water from a treated municipal supply, which is safe to drink but frequently has tastes and smells that are unpleasant due to chemicals like chlorine used to disinfect the water and keep bacteria and germs out. Additionally, depending on where you live, limescale deposits may accumulate in your mains water, which can clog pipes and harm appliances. Limescale buildup and chlorine taste/odor are only two of the many frequent water problems that may be resolved with water filtration. However, what is the real mechanism of water filters?
Mechanical
The primary principle of mechanical filtration is to use a barrier to physically remove any particles in the water, such as silt or debris. A ceramic filter with an incredibly complicated pore structure for ultra-fine filtering of pathogenic organisms is an example of a mechanical filter, as is a simple mesh filter that removes big trash.
A micron rating is often assigned to a mechanical filtration filter, indicating the filter’s effectiveness in terms of the size of the particles it can remove. Typical ratings that you may encounter include:
The majority of particles that are visible to the human eye will be eliminated by 5 micron.
Particles too tiny to be seen without a microscope will be eliminated by a 1 micron filter.
Giardia and cryptosporidium cysts will be eliminated at 0.5 micron.
Absorption
Carbon is most frequently used in water filters for absorption, and it is quite good at removing pollutants from the water. Carbon has a large interior surface that is crammed with cracks and crevices that may trap chemical impurities like chlorine, which is why it absorbs toxins so easily.
Granular activated carbon (GAC), which is included in the majority of household filters, absorbs and lessens undesirable tastes and odors. Carbon block elements, which are often more effective and typically have a micron rating for particle removal, are used in more costly filters.
Wood and coconut shell are two examples of materials that may be used to create carbon for filters; the latter is more costly but more efficient.
Sequestration
Chemically isolating a material is known as sequestration. In order to block the calcium and magnesium minerals that lead to corrosion and limescale, food-grade polyphosphate is frequently utilized in scale-inhibiting filters. However, scale is just inhibited rather than completely eliminated by polyphosphate, which is often only added in very tiny amounts. This indicates that rather than softening the water, polyphosphate keeps the minerals in the solution and stops them from scaling any surfaces they come into touch with.
Not all applications can benefit from scale inhibition since the hard minerals are still present in the water. Water locations with alkalinity levels of 180 ppm or above (extremely hard water) and applications where water is maintained at a constant temperature of 95°C or higher are often better served by water softening utilizing a technique like ion exchange.
Exchange of Ions
Ion exchange is a technique that softens hard water by substituting other ions, like sodium or hydrogen ions, for the calcium and magnesium ions present in hard water. Ion exchange, as opposed to scale inhibition, physically eliminates the hard minerals, lowering limescale and preparing water for uses requiring a steady high temperature, such as commercial coffee makers.
The most popular way to perform ion exchange is via an ion exchange resin, which often takes the shape of tiny beads. Some water softeners employ a similar kind of resin, and in the case of a water softener, the resin uses sodium ions, which must be refilled on a regular basis to keep the resin from losing its effectiveness. Water filters are typically sealed components, thus replacing the filter with a new one is easy. However, it should be mentioned that
It is possible to return and regenerate Calcium Treatment Units (CTUs) to the provider.
Since the legal maximum for the amount of salt (sodium) that can be in drinking water is 200 milligrams per liter, resins that employ sodium ions are often not used in drinking water filters. A hydrogen-based ion exchange resin is the recommended choice for filters as sodium ion exchange raises salt levels.
Osmosis in reverse
By pushing water through a semipermeable membrane under pressure, reverse osmosis (RO) removes dissolved inorganic solids (such calcium and magnesium ions) from the water while leaving the majority of the pollutants behind.
In order to return water with few impurities left, reverse osmosis—a very effective method of purifying water—is typically used in conjunction with several additional filters, including an absorption (activated carbon) filter and a mechanical (sediment) filter.
Although some waste water must be delivered to the drain, reverse osmosis systems employ water pressure to push water through the membrane without the need for energy. Although the additional filters needed for multi-stage water filtration can make a reverse osmosis unit more costly than other filtration techniques, RO provides the best level of filtration available in applications requiring 99.9% pure water and is increasingly being used to treat coffee water.