Filtration

There are several main types of water filtration that include reverse osmosis, distillation and carbon absorption.

Reverse Osmosis
This process uses a semipermeable membrane to remove ions, molecules and other larger particulate from drinking water. This is done by applying pressure to overcome the osmotic pressure on one side of the membrane forcing the water through and to the opposite side. This process can remove many types of bacteria and can be used in a wide range of commercial and domestic areas.

In larger RO systems, many of these semipermeable membranes are contained within pressure vessels and run in sequence with each other, with one stage feeding into another to produce clean drinking water.

This membrane rejects ions by a charge phenomena action, the larger the charge the greater the rejection by the membrane.RO is highly effective at removing TDS, turbidity, asbestos, lead, other heavy metals, chlorinated pesticides and heavy VOCs.

Benefits:

Low maintenance costs
Effective removal of many common and potentially dangerous virus, bacteria and chemicals

Distillation
One of the oldest forms of water purification is the distillation process. Water is heated to boiling point, next the vapour is cooled and condenses into a collection area. Most of the undesirable parts of the water are left behind, such as salts. However, Herbicides and Pesticides with boiling points lower than 100 degrees Celsius cannot be removed and will be present in the evaporated water. The process also kills off any harmful organisms such as viruses and bacteria, however distilled water tends to be more acidic and usually lacks oxygen giving the water a flat taste, this leads the water to be used in more industrial processes.

Benefits:

Removes a large variety of contaminates and kills bacteria and viruses
Relatively simple concept

Carbon Adsorption
Carbon adsorption is a type of filtration that many people will be familiar with due to its commonality within the household. Carbon filters are used in many portable water filtration containers such are Brita. Carbon absorption works through and is controlled by the size of the pores within the carbon filter and how fast the water is passed through the filter. These pores trap contaminants and impurities removing them from the water.

Carbon filters can be effective against a range of contaminates such as chlorine, odour and has the potential to remove lead, asbestos, cysts and coliform. However, this is dependent on the type of carbon used.

Activated carbon which is made from organic matter that is high in carbon, can remove microorganisms, pesticides, THMs, Trichloroethylene and PCBs this again depends on the type of carbon used, the flow of water and the frequency of use.

Benefits:

Removes organic particulate and chlorine effectively
Long life

In reality most of these processes are used in conjunction with one another, having a carbon filter come before the RO membrane reduces the strain on the membrane, prolonging the lifespan of the system. Other types of filtration are Microporous Basic Filtration, Ion Exchange and Ultraviolet (UV). In many cases, these are used in combination with the other filtration methods that have been discussed above.

​Filtration

Filtration