An activated carbon water filter, or sometimes called activated charcoal, is a form of a water filtration process that uses a filter that is produced using ground carbon with increased surface area to remove impurities and contaminants in water. The activated carbon filters are mainly used to remove carbon-based organic chemicals/compounds and chlorine as well as bad taste, odors, and some heavy metals whilst other impurities or constituents are able to pass through.
The main components of a carbon water filter system include an inlet system through which water flows into the vessel prior to treatment, a vessel in which the extremely porous activated carbon media is housed, a riser tube through which treated water flows before getting out of the vessel via the outlet pipe. The activated carbon water filter system also has a backwash pipe used to flush out the trapped silt and to eliminate carbon fines that are suspended solids arising from the friction between the carbon granules. At this point, it is important to know how a water filter works.
The main advantage of using an activated carbon water filter is its ability to eliminate organic compounds, chlorine, chlorine by-products, bad odor, taste, some heavy metals, and high turbidity. Conversely, the activated carbon filters are not able to remove all impurities like inorganic compounds, some microorganisms, and dissolved solids
What is an Activated Carbon Filter?
An activated carbon water filter is a water filtration system that uses a highly porous carbon-based medium to retain impurities and let clean water pass through the physical process of adsorption. The carbon medium can be granular, carbon blocks or radial flow carbon filters in nature. Due to the highly porous nature of activated carbon media, it is estimated that 1 gram of activated carbon has a surface area ranging between 300 and 2000 m2. Consequently, impurities and constituents get attached to the activated carbon surfaces such that the activated carbon with higher surface areas have also a higher capacity of adsorbing contaminants and also a higher capacity of water filtration.
Frederick Lipscombe was the inventor of the carbon water filter for potable water treatment. It is different from other types of water filtration systems like reverse osmosis, sediment filter, or ultrafiltration in that it uses the process of adsorption to retain contaminants. The Activated Carbon Filtration System for Home use is one of its most popular applications.
The activation of the carbon filters can be done through one of the following 2 mechanisms:
1. Thermal Activation
Thermal activation is the process of burning carbon at extremely high temperatures of between 800 and 1000 oC without oxygen, but using steam resulting in water–gas reactions thus gasifying the carbonized material. With the introduction of air, gases are burnt out without burning the carbon, thus, resulting in extremely porous and activated carbon that is graded, screened, free of dust, and generally having fine pores.
2. Chemical Activation
Chemical activation is the process of exposing raw carbon to strong dehydrating agents like powerful chemicals mainly acids, strong bases or salts for example phosphoric acid or zinc chloride before exposure to heat in the range of 500 and 800 oC which activates the carbon. In contrast to thermal activation, chemical activation results in bigger pores spaces such that it is ideal for activating the carbon filters used in the adsorption of larger pore molecules or contaminants.
How Does an Activated Carbon Filter Work?
Activated carbon filters work by using the principle of physical adsorption to treat water. The water under treatment flows through the extremely porous activated carbon filters and the intermolecular forces draw molecules into the millions of pores on the surface of the activated carbon. As a result, contaminants get physically adsorbed onto the surface area of the activated carbon and the treated water flows out of the filter ready to be used or treated further.
The higher the surface area, the more impurities activated carbon can capture. Once all the surface area is occupied, then the activated carbon filter stops working as there will be no more surface area for adsorption to take place. Under those circumstances, the carbon filter needs to be replaced with a new one otherwise the contaminant laden water will get used with the belief that it is treated. Therefore, it is very critical that carbon filters get replaced on time.
What is Chlorine Removal?
Chlorine removal is the process of eliminating residual chlorine in the water which is always associated with a poor taste and odor of the treated water. Activated carbon filters can remove the residual chlorine. When water rich in chlorine gets in contact with activated carbon, molecules from both chlorine and carbon react to form a new product, namely chloride ions, thereby removing chlorine from the water. Some good quality activated carbon filters have been recorded to remove 95% or more of residual chlorine in the water. Due to the fact that the process of chlorine removal is quite fast, this needs a huge surface area of the activated carbon to prevent fast filling up of pores that reduce the effectiveness of the activated carbon filter or warrants an early replacement of the carbon filter.
The process of chlorine removal is important because chlorine by-products in the water value chain include the formation of trihalomethanes (THMs) which are compounds that are formed when chlorine reacts with organic matter in the water being treated. Many of the THMs are environmental pollutants and also a major public health concern as they are carcinogenic. Activated carbon is also effective in the removal of chlorine by-products.
The removal of chlorine using activated carbon has its own downside. As chlorine is removed from the uppermost layer of the carbon media, the activated carbon creates a moist environment that promotes the growth and abundance of bacteria which can create secondary bacterial infection and treatment challenges in the water treatment process.
What is Removal of Organic Matter?
The removal of organic matter and compounds is a process through the physical mechanism of adsorption. As water flows through the highly porous activated carbon media, intermolecular forces draw molecules into the millions of pores on the surface of the activated carbon. As a result, contaminants get physically adsorbed onto the surface of the activated carbon and the purer water flows out of the filter ready to be used or treated further. Activated carbon has been documented to remove all 32 identified common organic contaminants including TMHs, all listed 14 common pesticides, the most popular herbicides, nitrates, phosphate, pharmaceuticals, and microplastics.
The rate of adsorption of organic matter depends on several factors including the physical properties of the activated carbon, the chemical composition of the carbon source, the chemical composition of the contaminants, the temperature and pH of the water as well as residence time of the water in contact with the carbon media.
The removal of organic matter in water is important because although at low concentrations, most of the organic compounds pose little threat to human health, at higher concentrations the risk increases. Likewise, a lot of the contaminants have a bearing on the environment if not adequately treated.
The History of Activated Carbon Filters
The invention of activated carbon filters can be traced from the Ancient Egypt era when charcoal was used to smelt ores to create bronze around 3750 B.C. and to eliminate unpleasant odors around 1500 B.C. In the water sector, around 400 B.C. activated carbon was recorded to have been used in the purification of water by the Ancient Hindus and the Phoenicians.
In 1773, chemist Carl Wilhelm Scheele quantified the adsorption forces for porous carbon using gases. In 1862 Frederick Lipscombe made a breakthrough by making inroads into the commercial application of the concept of activated carbon in the treatment of potable water.
The first production of activated carbon on an industrial scale was at the beginning of the 20th century with a chemical plant being built in 1909 to produce carbon for commercial use. In the present day, the biggest use of activated carbon is in the municipal treatment of water through the removal of organic compounds and chlorine.
What’s Inside a Carbon Filter
There are 3 different types of activated carbon filters depending on the source of the carbon medium used namely the bituminous coal, peat or coconut shells. The most common carbon source is coconut shells as they are renewable and are made from the shell (and not the inside of the coconut), thus, eliminating the risk of allergic reactions or flavored water. The use of bituminous coal is now less due to the occurrence of arsenic in some of its carbon media, thus, exposing the risk of arsenic contamination. The carbon can also be sourced from wood that would have been burnt and ground into granules.
The carbon particles can be very small and fine with fine pores which are good at treating water with small contaminant molecules. Conversely, the bigger carbon particles leave bigger pore spaces and are good at treating water with contaminants with bigger molecules.
Types of Carbon Filters
There are 3 types of carbon filters namely Granular Activated Carbon Filters, Carbon Block Filters, and Radial Flow GAG Carbon Filters.
1. Granular Activated Carbon (GAC) Filters
Granular activated carbon filters are filters with large and loose granules of carbon whose external surface area is smaller as compared to the other activated carbon types. Due to the loose nature of the carbon granules, they allow water to flow through the media easily and are common in water treatment.
The advantage of granular activated carbon filters is that they are granular in nature and hence easily and quickly allow the movement of water under treatment through the media. The disadvantage of granular activated carbon filters is that they are prone to channeling because of the loose nature of the carbon granules resulting in water creating well-defined paths through the carbon media and thus allowing contaminants to pass through without being retained on the surface of the carbon granules. Furthermore, GAC filters have lower quality filtration due to the fact that there is less residence time and larger pore sizes compared to other filtration types.
Granular activated carbon filters can be used as whole house or point of entry filtration systems but excluding outside faucets or can be used as a point of use filtration systems where they can be installed as an under-sink system, as a filter pitcher, or as filters that come installed in refrigerators. In order to procure the correct GAC, one needs to consult the Granular Activated Carbon Filter Buying Guide.
2. Carbon Block Filters
Carbon block filters are filters with much finer carbon particles that are held together using a binding agent to form a block through which water can pass during filtration. As a result of the fact that the carbon particles are smaller and densely packed, leaving smaller pore spaces, although the surface area of the carbon particles (through which water flows) is higher. As such the residence time is longer and is able to retain more impurities compared to GAC.
The advantages of the carbon block filters are that they are able to remove more constituents resulting in purer water than other carbon filters like GAC. The high residence time means that the carbon block is able to conduct a more thorough filtration process that can eliminate bad odors and other constituents of more health concerns compared to GAC. On the other hand, the high contact time makes the filtration process slower and makes the system unsuitable where high flow rates are needed. Additionally, due to the small pore sizes, the carbon blocks are prone to a build-up of organic matter and sediment, thus, need regular cleaning of the accumulated filtrate. Due to the wide range of carbon block filters, one needs to refer to the Carbon Block Water Filter Buying Guide.
3. Radial Flow GAC Carbon Filters
Radial flow GAC filters are filters that combine the best features of both the GAC and the carbon block by having a high surface area of the carbon block and the filtration rates of the GAC. The radial flow GAC filter is uniquely designed in such a way that water flows to the filter through the side of the cartridge in a radial manner like a carbon block but contains granules for increased flow like the GAC. The radial flow GAC filter is able to achieve high flow rates with little or no carbon fines in the treated water.
The advantage of the radial flow GAC filter is that the filter is able to treat water to a better quality than the GAC and yet still maintain a higher flow rate that is characterized by little or no pressure drops. For more information on the available options, refer to the Radial Flow GAC Carbon Filter Buying Guide.
Advantages of Activated Carbon Water Filters
The advantages of activated carbon water filters are as follows:
- Residual chlorine removal: Activated carbon water filters are effective in the removal of 95% or more of residual chlorine in treated water.
- Taste and odor improvement: As a result of the carbon filters’ ability to remove the residual chlorine in water, they effectively eliminate the poor taste and odor associated with residual chlorine in the water.
- Elimination of chlorine by-products: Activated carbon filters significantly reduce the health hazards associated with the by-products of chlorine in the water. The main by-products of health concern are THMs which are linked with being carcinogenic.
- Increase in surface area for adsorption: During the carbon activation process, the carbon particles become extremely porous just significantly increasing the surface area over which adsorption/treatment can take place. As such the vessels in which carbon media will be put might be small, but the surface area over which adsorption will take place can be thousands of square meters thus improving the effectiveness of the water treatment process.
- Wide range of carbon filter applications: Carbon filters can be used in different setups including point of entry use and widely in point of use systems like refrigerators, pitcher filters, and under sink systems.
- Removal of most contaminants: In general, activated carbon filters are effective in removing over 80 chemicals and reducing over 50 chemicals during the water treatment process. Furthermore, it is the only filtration system that removes all 12 identified herbicides and 14 pesticides as well as all 32 organic contaminants.
- Retainment of healthy minerals: Activated carbon filters are able to remove the undesired pollutants in water whilst leaving out useful minerals like calcium, magnesium, and sodium in the water under treatment.
- Recycling of carbon filters: Some of the activated carbon filters can be recycled. Under these circumstances, the used adsorbed carbon filter is desorbed and re-activated thus permitting the carbon to be used repetitively.
- The small footprint of the water filter: The GAC has a small footprint making the system very suitable for setups with limited space.
What Does an Activated Carbon Filter Remove?
Activated carbon filter systems can effectively remove the following groups of contaminants from water at industrial, municipal, and household levels:
- Chlorine: Chlorine is removed through the chemical reaction with carbon resulting in the formation of chloride.
- Bad taste and odors of water: By eliminating residual chlorine which is associated with bad taste and odor, such undesirable characteristics of water are removed in the process.
- Chlorine by-products: The most common chlorine by-product that carbon filters eliminate are trihalomethanes (THMs) which are potentially cancerous.
- Chloride: Activated carbon can eliminate chloride in water. This can be natural or can be elevated by the conversion of chlorine.
- Pesticides: Activated carbon filter systems are able to remove the 14 most common pesticides
- Herbicides: activated carbon is one filtration system that can remove all 12 of the most common herbicides.
- Phosphate: Good quality charcoal filters are able to remove 70 to 90% of phosphates in water.
- Nitrate: Activated carbon filters can remove between 50 and 70% of nitrate in water. Nitrate is one of the problematic nutrients in the water and can cause methemoglobinemia.
- Pharmaceuticals: High-quality carbon block filters are able to remove about 95% of pharmaceuticals that might have entered the water system from poorly managed production sites.
- Microplastics: Some carbon block filters are able to remove microplastics that are as a result of plastic waste which when exposed to environments like the sun or oxygen can cause them to break down and can potentially cause human health problems.
- Heavy metals: Some filter pitchers are certified to remove specific heavy metals for example lead or mercury or reduce arsenic that is poisonous to human health.
Can Activated Carbon Remove Bacteria?
Traditionally activated carbon filters cannot remove bacteria because of the primary mechanism of adsorption in which carbon filters work. Bacteria do not react with carbon and get physically adsorbed on the carbon filter surface as other contaminants do. As such bacteria are generally able to pass through most of the pore spaces of the carbon filters and therefore are not effective in removing bacteria.
However, some of the recent developments especially for carbon blocks have enabled the filters to remove some bacteria types. This is purely based on the pore size of the filters and not primarily on the mechanism through which activated carbon filters are designed to work. Such carbon blocks that have much smaller pore sizes result in some bacteria types becoming too big to pass through the pore spaces and therefore getting trapped and eliminated for example the Multipure solid carbon blocks that have pore spaces of 0.5 microns thus making some bacteria about 10 times bigger than the pore size. This phenomenon will not be applicable for GAC because of the bigger pore spaces.
Do Carbon Filters Remove Viruses?
No, carbon filters cannot remove viruses because viruses do not react with carbon and get physically adsorbed on the carbon filter surface as other contaminants do. Some of the best solid carbon blocks have pore spaces of about 0.5 microns, yet, viruses have sizes ranging between 0.01 and 0.1 microns. This makes it possible for viruses to pass through the smallest pores of the carbon filters hence carbon filters are not able to remove viruses.
Why is Activated Carbon Beneficial?
The following are health benefits of using activated carbon:
- Activated carbon can be used as an emergency treatment for poisoning.
- Activated carbon may promote kidney function.
- Reduces symptoms of fish odor syndrome.
- Activated carbon helps digestion.
- Helps cure bug bites.
- Activated carbon can strengthen one’s hair.
- Whitens teeth.
Does Activated Carbon Waste Water?
Yes, activated carbon wastes water in a sense. The GAC system has regular backwashing is an integral part of the system. This process will flush out the trapped silts and eliminate carbon fines arising from the friction between the carbon granules. The water that is used to conduct the backwash is taken out of the vessel and disposed of.
The wastage of water by activated carbon water filtration systems can be prevented through re-introducing the flushed water into the system after undertaking some settling and filtration to minimize introducing the filtrate into the activated carbon system again.
Is Activated Carbon Good for the Environment?
The activated carbon system has some advantages and disadvantages from an environmental perspective. The advantages of activated carbon for the environment include the fact that it is able to eliminate some contaminants that would otherwise end up polluting the water system like pesticides, herbicides, nitrate, and pharmaceuticals. The activated carbon water filtration system, therefore, has some benefits for the environment from a pollution prevention perspective.
However, as indicated above, the process of backwashing generates water with some wastes. In order to prevent environmental pollution, this wastewater needs to be properly disposed of or recycled to avoid those wastes entering the water system again. Instead of disposing of the backwash via the wastewater system, it can be separated to avoid re-contamination and properly pre-treat the water before reuse or disposal.
Is Activated Carbon Water Good for Health?
Yes, activated carbon water is good for health. The health benefits of activated carbon water include:
- The water is devoid of chlorine by-products that prevent the formation of THMs that are linked to cancer.
- The harmful products like herbicides, pesticides, pharmaceuticals, microplastics, and nitrates are removed from the water under treatment thus making sure that humans consuming that water will not ingest these contaminants.
- Some specific carbon filters like carbon blocks are able to remove microbial cysts, bacteria, heavy metals, and asbestos which is all harmful to human health.
- Due to the fact that activated carbon filters do not eliminate inorganic minerals like magnesium, potassium, sodium, and calcium, the treated water is not devoid of the healthy minerals that human bodies get in the water.
Are Carbon Water Filters Safe?
Carbon filters are safe if they have been certified by independent associations. The filters are certified by different and neutral associations e.g. the National Sanitation Foundation (NSF) and the American National Standards Institute (ANSI). As such the results that are published about the carbon filters performance, safety, rating (for chlorine, taste, and odor), and the removal of contaminants. This means that the results published by the manufacturer on the specifications of the activated carbon filter are true, meet the set standards, the design is safe, and that there is no addition of harmful constituents by the filter system to the treated water.
Where Should One Use a Carbon Water Filter?
Activated carbon water filters can be used either as a point of entry or point of use systems. If one wants clean water for the whole home, an activated carbon system is ideally installed as a point of entry system at such a point that it filters all the water that gets into the house and excludes water that will be used outside for example in the garden or for the lawn to avoid unnecessary filtration of non-potable water. Alternatively, the carbon filter can be installed at the point of use depending on where one wants the water to be filtered for example as an under sink system, at different faucets, or on shower heads.
However, carbon filters can be used in different environments where clean and safe water is needed. These include use in:
- Water and wastewater treatment works
Should You Change Your Carbon Filters?
Yes, one should change the carbon cartridges of the carbon filter as per the manufacturer’s recommendation because, during water treatment, contaminants get attached to the filter surface. Once all the surface area is occupied, then the contaminants will flow with the water into the water supply, thus exposing the users to the different impurities. Therefore, it is very critical that filters get replaced on time to avoid contaminated water being used.
How Often Should You Change Your Carbon Filter?
The carbon cartridges need to be replaced every 6 to 12 months. Some of the activated carbon blocks can be recycled such that the used adsorbed carbon filter is desorbed and re-activated thus permitting the carbon to be used repetitively without replacing it.
What is the Lifespan of Activated Carbon Filters?
The lifespan of activated carbon filters is 6 to 12 months. A person should not use the filter beyond 12 months without recycling it. To prolong the lifespan of an active carbon filter, one needs to recycle the activated carbon through desorption and re-activation.
How to Choose a Quality Carbon Water Filter?
There are several factors that one needs to consider when choosing a quality carbon water filter:
- Target contaminants to be removed by the carbon filter: Although generally, most activated carbon filters are able to remove similar impurities, some filters have additional contaminants that they are able to remove for example lead, chromium as certified by different associations e.g. the National Sanitation Foundation (NSF), American National Standards Institute (ANSI). Some filters are not able to remove some contaminants therefore it is important to carefully consider that factor.
- Filter lifespan: It may be ideal to select an activated carbon with a filter that does not have a very long lifespan to prevent the accumulation of bacteria and other microbes that can end up contaminating the water.
- Cost of carbon filter: This has a bearing on the affordability of the activated carbon filter by the user.
- Cost of filter replacement: This has a bearing on the cost of operating the carbon filter system.
- Filter indicator: Some of the best activated carbon water filters now have inbuilt filter indicators to assist the user to know when to change the filter cartridge. This will help in preventing a scenario where contaminated water goes through to the tap when the surface of the filter is all occupied by retained impurities.
- Presence of meter: Some best activated carbon water filters have meters like TDS, pH meter which help the user in monitoring the water being consumed.
What are the Activated Carbon Water Filter Brands?
The brands that produce activated carbon water filters are listed below:
- Lake Industries
- Golden Icepure
What are the Activated Carbon Water Filter Products?
Some of the most common activated carbon water filter products include:
- Point of entry carbon filter
- Under-sink carbon filter
- Countertop carbon filter
- Pitcher filter
- Compact dispenser carbon filter
- Faucet carbon filter
- Shower head carbon filter
Can You Wash and Reuse Carbon Filter?
Yes, some activated carbon filters can be cleaned and reused, thus recycled, a couple of times except for powdered filters. This is achieved through the removal of the used adsorbed carbon filter that is desorbed via running water so as to remove the impurities. After rinsing the media, one can place an ear next to the carbon media and listen for any sound. If there is some popping or cracking sound, it means that the carbon can be reused whereas if there is no sound, the carbon media needs to be replaced with fresh carbon. After rinsing the carbon media, it is vital that it gets reactivated with a rotary kiln, if available. The re-activated carbon can be used a number of times.
Which Activated Carbon Filters Should be Preferred?
The following are some of the most popular activated carbon filters:
- Frizzlife Under Sink Water Filter System
The average price of a Frizzlife Under Sink Water Filter System is $75. The benefits of using the Frizzlife Under Sink Water Filter System are that it removes over 99% of contaminants, is easy to install, and that it is NSF/ANSI Certified. The Frizzlife Under Sink Water Filter System can be used as an under sink water filtration, for the refrigerator, bathroom, and for icemaker.
- Omnipure K2333-KK 3/8″ Quick Connect
The Omnipure K2333-KK 3/8″ Quick Connect inline water filtration on average costs $10. The benefits of using the Omnipure K2333-KK 3/8″ Quick Connect include that it is cheap, is easy to install, and is NSF Certified.
- Aquasana EQ-600-AMZN
The Aquasana EQ-600-AMZN on average costs $700. The benefits of using this water filter are that it is a whole house water filter, removes most contaminants, is easy to install, has a high flow rate, and is NSF Certified.
- iSpring US31 Stage Under Sink Water Filtration
The iSpring US31 Stage Under Sink Water Filtration roughly costs $110. The benefits of using the iSpring US31 Stage Under Sink Water Filtration include the fact that it is easy to install, is NSF/ANSI Certified, and has a high flow rate.
- Camco 40043 Taste Pure RV Carbon Water-Filter
The Camco 40043 Taste Pure RV Carbon Water-Filter on average costs $20. This is an inline water filtration system. The benefits of using the system are that it is cheap, easy to install, NSF/ANSI Certified, and can be fitted on many facilities like home, hose, trailer, or a caravan.
- Pentair Pelican PC600-P Water 10 GPM Whole House Carbon Water Filtration System
The Pentair Pelican PC600-P Water 10 GPM Whole House Carbon Water Filtration System costs about $980. The advantages of using the Pentair Pelican PC600-P Water 10 GPM Whole House Carbon Water Filtration System are that it is a whole house water filter, removes most contaminants, is easy to install, is NSF/ANSI Certified, and has a high flow rate
- iSpring WGB21B 2-Stage Whole House Water Filtration System
The iSpring WGB21B 2-Stage on average costs $150. It is a whole house filtration system that can be installed as an under-sink system. The benefits of using the iSpring WGB21B 2-Stage Whole House Water Filtration System are that it is a whole house water filter that removes most contaminants, is easy to install, has a high flow rate, and is NSF/ANSI Certified.
- Lake Industries Stainless Steel Countertop Water Purifier Filter
The Lake Industries Stainless Steel Countertop Water Purifier Filter costs about $65. The benefits of using the Lake Industries Stainless Steel Countertop Water Purifier Filter are that it is easy to install, removes most contaminants, and is NSF Certified.
- APEX EXPRT MR-2050 Dual Countertop Drinking Water Filter
The average APEX EXPRT MR-2050 Dual Countertop Drinking Water Filter costs $115. The benefits of using this water filter are that it is easy to install, removes most contaminants, adds healthy inorganic nutrients, and is NSF/ANSI Certified.
- Aquaboon 2-Stage 20″ Whole House Water Filtration System
The Aquaboon 2-Stage 20″ Whole House Water Filtration System costs about $170. The benefits of using the Aquaboon 2-Stage 20″ Whole House Water Filtration System are that it is easy to install, is NSF Certified, removes most contaminants, and that it has a high flow rate.
What are the Other Water Filter Types That are Similar to Activated Carbon Water Filter?
The following are some of the water filtration systems that can be used as alternatives to Activated Carbon Filters, their similarities, and differences.
The similarities between reverse osmosis and activated carbon filters are that both filtration systems are able to remove suspended solids. Additionally, both reverse osmosis and activated carbon filters can remove chlorine and heavy metals. Furthermore, both treatment systems result in the production of wastewater. In contrast, reverse osmosis removes all constituents in water including all healthy minerals (dissolved solids) like calcium, magnesium, sodium whereas activated carbon filters are unable to remove those minerals. Also, reverse osmosis is able to remove all microbiological organisms like viruses, all bacteria, and parasites, unlike a few activated carbon filters that can remove some bacteria and parasites but are unable to remove all viruses from the water.
The kinetic degradation fluxion filters and the activated carbon filters are both water filter types that are able to remove chlorine and lead. Their main differences are that kinetic degradation fluxion filters use the process of redox (reduction-oxidation reaction) whilst activated carbon filters use adsorption to treat water.
Sediment filters and activated carbon filters are similar in that they can be used as point of entry water treatment systems. However, sediment filters and activated carbon filters differ in that sediment filters rely mainly on filtration of sediments and activated carbon filters use mainly adsorption and ion exchange to treat water. Sediment filters are mainly used to trap big sediments and particles whilst in contrast activated carbon filters can remove smaller contaminants, herbicides, pesticides, and some bacteria. Furthermore, sediment filters are mainly used as a pretreatment for other water filter types that can remove more contaminants like activated carbon filters.