Water filtration systems remove harmful contaminants such as toxic metals, disease-causing microorganisms, and organic and inorganic chemicals from the water supply, improving human and environmental health.
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While community water treatment facilities are useful, they cannot guarantee complete control over the contamination of water sources. Natural materials such as carbon, ceramics, and sand are some of the most efficient water filtration systems to protect against disease and water contamination.
Recent innovations in materials and water filtration and treatment technology have positively impacted the health of human populations worldwide and on remediating industrial pollution. This article will explore some of the most common water filtration materials and methods, providing an overview of how they are central to mitigating damage to health and the environment from human activities.
Carbon Water Filtration
Activated carbon is the most common type of material used for water filtration, particularly in domestic applications. Factors such as molecular weight, particle size, pH, surface area, and flow rate determine the purification ability of this material. Activated carbon is commonly produced from charcoal.1
Contaminants in the water adhere to the surface of activated carbon. This adherence is made possible by the carbon’s large surface area. Harmful compounds such as chlorine, organic pollutants, and volatile organic compounds (VOCs) can be efficiently removed using a carbon filter.2
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Toxins not successfully removed by carbon can include arsenic, copper, fluoride, and some viruses. Due to these restrictions, carbon filters can incorporate iron, manganese, hydrogen sulfide, or a sediment pre-filter to enhance the removal of certain harmful particles within water.
Ceramic Water Filtration
Ceramic water filters are inexpensive, versatile, and effective water filtration technology. Many types of ceramic filters exist on the market today, made of ceramic cartridge filters containing millions of minuscule holes. Contaminants are trapped in the half-micron pores within the filter as water passes through it. The technology was invented in the early 1800s, making it one of the oldest types of water filters.
The water filtration efficiency of a ceramic filter can be further improved by combining it with activated charcoal. Colloidal silver can also be used to prevent the growth of pathogenic microorganisms on the filter media.3
Ceramic filters have significantly affected the health of populations in developing nations, preventing harmful health conditions such as early childhood diarrhea, which is responsible for around 9% of worldwide annual childhood deaths.
Sand Water Filtration
There are two types of sand filtration: rapid sand filtration and slow sand filtration. Most often used in conjunction with other water purification methods, rapid sand filtration uses physical straining to trap large particles between the sand grains.
Within the slow sand filter, microorganisms such as bacteria, viruses, and parasites can travel through the sand and be absorbed into the sand particles. Often referred to as a bio-sand filter for its biological activity, a slow sand filter contains very fine sand, allowing for the removal of particles smaller than the spaces between the sand grains.
The term “bio-sand filter” comes from the dense biological zone within the sand's top layers following water filtration. While slow sand filtration is often used to treat groundwater, its principal use is in removing pathogenic organisms and organic matter in surface waters.4
Membrane Filters
This type of water filtration technology uses thin, semi-permeable materials to remove contaminants from drinking water to make it potable. Water is passed through minuscule pores in the material. Methods include reverse osmosis, ultrafiltration, and nanofiltration.5
Each method has different advantages and disadvantages. Reverse osmosis effectively removes contaminants and produces purified water, but removes beneficial nutrients, requires high water pressure, and generates wastewater. Ultrafiltration can effectively remove microorganisms but is less effective at removing smaller contaminants such as dissolved chemicals.5
Finally, nanofiltration is a balanced membrane filtration method. It can remove bacteria, organic chemicals, heavy metals, and requires less pressure than reverse osmosis. However, it is less effective than reverse osmosis at removing extremely small particles from water.5
How Different Materials Affect the Quality of Water Filtration
The water filtration material or method that should be chosen depends on the specific needs of the water filtration system. Multi-stage filtration methods are the most robust choice, but different materials can be employed in isolation in specific circumstances.
Simple systems can be employed for sediment removal using a sand/gravel pre-filter with an activated carbon or ceramic filter. This improves the taste and clarity of filtered water.5
A more robust system is required for municipal water treatment. One of the best options is to use a gravel/sand pre-filter, activated carbon filter stage, and final ultrafiltration stage to remove a wide range of dissolved and undissolved contaminants.
Some water sources can be highly challenging to treat, containing many complex contaminants. In this case, a multi-stage and multiple method filtration system is required. Filtration systems used for these water sources include pre-filtration, activated carbon, membrane methods such as nanofiltration or reverse osmosis, and can even incorporate remineralization methods.5
Conclusion
Each type of water filtration system has advantages and disadvantages depending on certain factors, such as the cost and efficacy of removal or the type of contaminants present in the water source.
Regardless of the chosen method, water filtration is a crucial technology that has improved the quality of life for billions of people worldwide and will continue to do so.
References and Further Reading
- Water Tech Advice (2022) Guide to Activated Carbon Filtration [online] Available at: https://watertechadvice.com/activated-carbon-filters/
- NEWater (2025) What Does a Carbon Filter Take Out of Water? [online] Available at: https://www.newater.com/what-does-a-carbon-filter-take-out-of-water
- Campbell, B (2024) What is a Ceramic Filter and How Does it Work? [online] Water Filter Guru. Available at: https://waterfilterguru.com/ceramic-water-filters/
- Dream Civil (2023) Slow Sand Filter | Working, Efficiency, Advantages & Disadvantages of Slow Sand Filter [online] Available at: https://dreamcivil.com/slow-sand-filter/
- Enviroliteracy Team (2024) Which filtration material leads to the best drinking water? [online] enviroliteracy.org. Available at: https://enviroliteracy.org/which-filtration-material-leads-to-the-best-drinking-water/#Membrane_Filters_Reverse_Osmosis_Ultrafiltration_Nanofiltration
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