Water purification occurs on both small and large scales and water filtering can provide clean, potable water for industrial applications as well as individual households.

During the filtration process, contaminants like suspended particles, parasites, bacteria, algae, viruses and fungi are decreased in concentration.

Water Filters

Water filters remove impurities from water such as sediment, taste and odor, hardness, and bacteria, resulting in cleaner water.

The 5 Types of Filters

There are 5 types of water filters

Mechanical Filters
Absorption Filters
Sequestration Filters
Ion Exchange Filters
Reverse Osmosis Filters

Mechanical Water Filters

The basic idea behind mechanical filtration is to use a barrier to physically remove sediment, dirt, or other particles from water.

Mechanical filters can range from simple mesh filters that remove large debris to ceramic filters with extremely complex pore structures that allow for ultra-fine filtration of pathogenic organisms.

A filter that uses mechanical filtration is usually given a micron rating, which indicates how effective the filter is in terms of the size of the particles it can remove.

The following are some examples of common ratings:

5 microns – Most particles visible to the naked eye will be removed.
1 micron – Will remove too small particles to see without a microscope.
5 micron – Cysts will be removed (giardia and cryptosporidium).

Absorption Water Filters

The absorption water filter, also known as a carbon absorption filter, is one of the most common types of water filtration systems.

These filters are frequently used to eliminate chlorine in municipal water, which is a byproduct of the chemical treatment process.

Contaminants that cause unpleasant tastes and odors in your water will also be removed by absorption filters.

An absorption filter is made up of carbon-based minerals in a matrix with numerous microscopic pores and pits.

This matrix’s raw material is derived from organic carbon-rich materials such as coconut shells and coal.

The matrix’s various pores trap unwanted particles in the water as it flows through it.

Eventually, an absorption filter must be replaced, or it will become too clogged with the captured pollutants.

If you have an absorption filtration system in your home, you may notice a drop in water flow or the return of contaminants into the water supply at some point.

These are signs that you should replace the filter. If you are using an activated carbon filter, professionals can re-activate it when its performance lags.

Absorption filters will not affect several of the contaminants that can get into your water, such as some heavy metals and chemicals.

This is one of the reasons that you shouldn’t select and install a water treatment system on your own but instead call on professionals to test your water first.

They will know the right type of filter to use to see that you receive the purified water you want.

Sequestration Water Filters

The action of chemically isolating a substance is known as sequestration. In scale inhibiting filters, food-grade polyphosphate is commonly used to sequester the calcium and magnesium minerals that cause limescale and corrosion.

Polyphosphate, on the other hand, is typically introduced in very small amounts and only inhibits scale rather than eradicating it.

This means that polyphosphate does not soften the water but rather works to keep the minerals in the solution, preventing them from forming scale on any surfaces with which they come into contact.

Scale inhibition is not suitable for all applications due to the presence of hard minerals in the water.

Water softening using a process such as an ion exchange is usually recommended in areas with alkalinity levels of 180ppm or higher (very hard water) and applications where water is kept at a constant temperature of 95°C or higher.

Ion Exchange Filters

Ion exchange is a method of softening hard water that involves exchanging magnesium and calcium ions in hard water for other ions such as sodium or hydrogen ions.

Unlike scale inhibition, ion exchange physically removes hard minerals, reducing limescale and making the water suitable for applications where a constant high temperature is maintained, such as in commercial coffee machines.

Ion exchange is most commonly performed with an ion exchange resin, which is typically in the form of small beads.

A similar type of resin is used in some water softeners, and in the case of a water softener, the resin uses sodium ions, which must be recharged regularly to keep the resin from becoming ineffective.

Because water filters are typically sealed units, you simply replace the filter with a new one; however, Calcium Treatment Units (CTUs) can be returned to the supplier and regenerated.

Because the quantity of salt (sodium) that can be present in drinking water is legally limited to 200 milligrams/liter, resins that utilize sodium ions are not commonly used in drinking water filters. Because sodium ion exchange raises salt levels, filters should use a hydrogen-based ion exchange resin.

Reverse Osmosis Filters

The process of removing dissolved inorganic solids (such as magnesium and calcium ions) from water by forcing it through a semipermeable membrane under pressure so that the water passes through but most of the contaminants are left behind is known as reverse osmosis (RO).

Reverse osmosis is frequently paired with additional filters, such as a mechanical (sediment) filter and an absorption (activated carbon) filter, to return water with few pollutants.

Reverse osmosis systems employ water pressure to force water through the membrane, thus there is no need for electricity, albeit some effluent is created and must be disposed of.

The additional filters required in multi-stage water filtration can make a reverse osmosis unit more expensive than other filtration methods, but in applications requiring 99.9 percent pure water, RO offers the finest level of filtration available and is increasingly being used to treat water used in coffee.

Types Of Water Filter Systems for Domestic Use

Under Sink Water Filters

There are several different types of the under-sink water filter system, including:

The Water Gem

The Water Gem is Europe’s best-selling DIY under-sink water filter system, and it is made in the United Kingdom from WRAS-approved materials.

This system includes everything you need to connect to your main water supply as well as a tap of your choice.

Taste Great Drinking Water System

The Taste Great Drinking Water System is designed to be installed without the assistance of a plumber.

It improves the taste and odor of municipal water by reducing chlorine and other chemicals found in municipal water supplies using granular activated carbon or ceramic filters.

Doulton Water Filters

Doulton water filters are made of ceramic and can remove more than 99.99 percent of pathogenic bacteria, disease-causing cysts and particles while allowing beneficial minerals to pass through.

The outer shell of this product can be cleaned to extend its life.

Everpure Water Filters

Everpure filters are high-end systems that can be used in a wide range of applications, including food service, vending, coffee and ice machines.

While Everpure filtration systems are primarily used in commercial applications, they also provide the same advanced technology in your kitchen.

Counter Top Water Filters

Countertop water filters are portable water systems that do not require plumbing or installation and are ideal for transporting to areas with contaminated water.

A diverter pipe connects to a tap and directs water through a filter and out of the countertop system’s spout – simple but effective.

Water Filter Taps

Water filter taps are more expensive items that replace the existing faucet.

3-way filter taps designed for regular home use provide instant hot, cold and filtered water, offering an all-in-one solution for your domestic water needs.

Boiling water taps that save time and energy are ideal for use in situations where boiling water is required regularly.

Water Filter Housings

Water filter housings are long-lasting protective casings designed to house replaceable water filter cartridges.

We can provide housings suitable for reverse osmosis membranes in a variety of sizes and mounting options.

Calcium Treatment Units (CTUs)

Calcium Treatment Units, or CTUs, have been the industry standard for many years in commercial food service and vending applications for reducing limescale and improving taste and odor.

CTUs use a de-alkalization process and can be used in coffee machines, combination ovens, baking ovens and water boilers.

References

[1] Aqua Cure. n.d. Aqua Cure. [online] Available at: <https://www.aquacure.co.uk/knowledge-base/how-water-filters-work#mechanical_filters> [Accessed 14 March 2022].

[2] TUSSERSER, C., 2020. What is Water Filtering? [online] Water & Wastes Digest. Available at: <https://www.wwdmag.com/water-filtration/what-water-filtering> [Accessed 14 March 2022].

[3] The Trusted Plumber. 2015. What Are Absorption Water Filters? [online] Available at: <https://www.thetrustedplumber.com/blog/water-treatment-systems/what-are-absorption-water-filters/> [Accessed 14 March 2022].