Different Types of Water Filters

A water filter removes any impurities from water, such as bacteria, waste, sediment and odour, lowering the contamination of water in order for it to be drinkable. If you’re thinking about investing in a water filter, here are the five different types of water filters you can consider.

Mechanical filters

A mechanical filter removes the impurities from water by physically removing any sediment, dirt or other harmful particles by using a barrier. They can be in the form of a mesh that filters out any debris, or a ceramic filter with a complex pore structure that filters out pathogenic organisms which can cause illnesses. Mechanical filters will usually have micron ratings. This indicates the effectiveness of the filter, which will depend on the size of the particles it is capable of removing. These are the common ratings you might see:

• 5 micron – this means the filter will remove particles that are visible to the naked eye.
• 1 micron – this means the filter will remove particles that you can only see with a microscope.
• 0.5 micron – this means the filter will be able to remove cysts, such as giardia – a  tiny parasite that causes a diarrheal disease called giardiasis.

Absorption filters 

Absorption will usually be carried out by carbon – an element that is highly effective in catching water-borne contaminants. This is due to carbon having a large internal surface capable of trapping chemical impurities like chlorine. If you have a domestic filter, they will usually have a GAC, which stands for granular activated carbon. By using absorption, the GAC will reduce unwanted tastes and odours. There are also filters that use carbon block elements – these are more effective but are also more expensive.

Sequestration filters

Sequestration filters chemically isolate a substance. It’s also known as a scale inhibiting filter, which uses food grade polyphosphate to isolate the calcium and magnesium minerals that cause limescale and corrosion. However, the polyphosphate is only released in small amounts and only isolates substances instead of removing them completely. This means that the minerals are kept within the solution but are prevented from forming as scale on surfaces they might come in contact with. Due to these minerals being present in the water, scale inhibition is not suitable for every appliance.

Ion exchange 

Ion exchange is a process that exchanges the calcium and magnesium ions found in water with sodium and hydrogen ions, which softens water. Unlike a sequestration filter, ion exchange filters will remove the hard minerals present, reducing limescale. It will also enable water to be suitable for appliances where water has to be kept at a high temperature, such as commercial coffee machines. Ion exchange filters will usually use a resin in the form of small beads.

Reverse osmosis filters 

Reverse osmosis filters force dissolved inorganic solids, such as calcium and magnesium ions, through a semipermeable membrane. These ions are usually forced out by water pressure and are left behind when water flows through. These filters are highly effective in purifying water and is usually a combination of a mechanical filter and an absorption filter. Since these filters utilise water pressure, they don’t use electricity, but they can produce waste water.

These are the five different types of water filters you can consider if you’re thinking of investing in one. For any enquiries or if you’d like to know more about water filtration, don’t hesitate to contact any of our water experts here, as well as our plumbing services here.