The Science Behind Water Filtration: How Does a Water Filter Work?

One of the most significant elements in the world, water makes up 71% of the Earth’s surface and can make up as much as 75% of a person’s body. Agriculture, science, medicine, transportation, heating, recreation, food processing, washing, and perhaps the most important of all – drinking!

The technical details of water filtration

Water filtration is the process of removing impurities and contaminants from water to make it safe and suitable for consumption. Water purification typically consists of several stages, which may differ depending on the specific contaminants present in the water and the desired level of filtration.

Here are some of the technical details of water purification:

  • Screening and Pre-treatment: Water from its source is screened to remove large debris and materials such as leaves, sticks, and large sediment. After that screening, the water is often treated with chemicals like chlorine to disinfect it and prevent the growth of bacteria.
  • Coagulation and Flocculation: This process involves adding chemicals to the water to cause small particles to come together and form larger clumps, called floc.
  • Sedimentation: The water is then allowed to settle so that the floc can sink to the bottom of the container.
  • Filtration: Once the floc has settled, the water is passed through various filtration systems to remove any remaining particulates and contaminants.
  • Disinfection: After filtration, the water is disinfected to kill any remaining bacteria, viruses, and other harmful organisms. Common disinfectants include chlorine, ozone, or ultraviolet (UV) light.
  • pH Adjustment: Finally, the pH of the water may be adjusted to ensure it is at a safe level for consumption.

It’s important to note that some water sources may require additional purification steps, such as reverse osmosis, distillation, or activated carbon filtration, depending on the level and type of contaminants present.

Various methods used in water filters

Water filter is a device that removes impurities from water by physically or chemically removing contaminants. There are several methods used in water filters, and here are some of the most common ones:

Reverse Osmosis

This is a highly effective method that forces water through a semipermeable membrane that separates impurities from the water. It can remove up to 99% of impurities, including minerals and heavy metals.

Ultraviolet Purification

UV light can be used to destroy bacteria, viruses, and other microorganisms in the water. This method is commonly used in combination with other filtration techniques.

Activated Carbon Filters

These filters use activated carbon to adsorb impurities like chlorine, organic compounds, and other chemicals that can affect the taste and odour of the water.

Ceramic Filters

Ceramic filters use porous ceramic to filter out impurities like bacteria and sediment.

Ion Exchange

Ion exchange filters use resin beads to remove minerals like calcium and magnesium from the water. This is especially useful in areas with hard water that can cause mineral buildup in appliances and pipes.


Distillation is a process that involves heating water until it turns into steam, which is then condensed back into the water. This method is effective at removing impurities, but it can be time-consuming and energy-intensive.

Gravity Filters

These filters rely on gravity to force water through a filtering material. They are often used for outdoor activities like camping and hiking.

There are many other methods used in a water filter, and the best method for you will depend on the type and amount of impurities in your water. It’s important to do your research and choose a filter that is certified by a reputable organisation to ensure its effectiveness.

Most popular water filtration methods – RO, UV and MF

RO (Reverse Osmosis), UV (Ultraviolet), and MF (Microfiltration) filters are all different types of water filtration methods that are commonly used to purify water.

RO filters use a semi-permeable membrane to remove dissolved solids and impurities from water. Water is forced through the membrane under high pressure, leaving behind contaminants and impurities. RO filtration is highly effective at removing contaminants such as arsenic, lead, fluoride, and nitrates.

UV filters, on the other hand, use ultraviolet light to kill bacteria and other microorganisms in the water. When water is passed through a UV chamber, the UV light disrupts the DNA of bacteria and viruses, rendering them harmless. UV filtration is highly effective at killing harmful microorganisms in the water, but it does not remove dissolved solids or other impurities.

MF filters are a type of physical filtration that uses a membrane to remove particles, bacteria, and other impurities from water. These filters have a pore size of 0.1 to 1 micron, and can effectively remove bacteria, cysts, and some viruses. However, MF filters are not effective at removing dissolved solids or other chemicals from the water.

Each of these filters has its unique benefits and drawbacks, and the best option for you will depend on your specific needs and the quality of your water supply. In some cases, a combination of these filters may be used to provide comprehensive water purification.

The best combination is considered to be a RO+UV water filter. RO+UV water purifiers are devices that use both reverse osmosis (RO) and ultraviolet (UV) technologies to purify water. Reverse osmosis is a process that removes dissolved impurities, such as heavy metals, salts, and chemicals, from water by forcing them through a semipermeable membrane. UV technology, on the other hand, uses ultraviolet light to kill bacteria, viruses, and other microorganisms that may be present in the water.

Combining these two technologies in a single purifier can provide more thorough purification and ensure that the water is safe and free from impurities. Pureit Ultima Eco Mineral RO+UV+MF Water Purifier with 10L Storage, for example, uses RO+UV technology to remove dissolved solids, bacteria, viruses, and other harmful contaminants from the water.

In conclusion, RO+UV water purifiers are commonly used in homes, offices, and other settings where clean and safe drinking water is essential. Some advanced models also feature additional filters, such as activated carbon filters, to further improve the taste and odour of the water. However, it is important to note that a RO+UV water filter may not be effective in removing certain contaminants, such as volatile organic compounds (VOCs) and heavy metals, and may not be suitable for purifying very hard water.

For more water filter-related information you can follow the official of Pureit India.

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