Carbon block filter plays an integral role in modern filtration systems.

That’s why at FilSon, we strive to help you get the best carbon filters by availing all the vital information you need.

Whether you want to learn about structural design, benefits, uses, classification or available alternatives in the market – the information you’re looking for is right here.

Let’s dive right in.

What is Carbon Block Filter?

A carbon block filter is a device that assists in the filtration process of water.

It is a barrier that will capture materials that contaminate drinking water.

In the past, it provided an effective technology in the Point of Use [POS] in the drinking water treatment firms.

It can work independently or with other filtration devices.

carbon block filter

Carbon block filter

What are the Advantages of Using a Carbon Block Filter?

There are several benefits to using a carbon block filter.

Some of them include:

Elimination of Contaminants

The porosity of carbon block filters is very high.

This implies that, almost like a sponge, carbon block filters will filter and wash water as it goes through it.

Also, carbon block filters do not use any chemicals.

They therefore may not strip the water of the naturally occurring salts and minerals.

These filters can eliminate impurities like:

  1. Asbestos
  2. Cysts
  3. Chlorine
  4. Lead
  5. Some pesticides
  6. Trihalomethanes
  7. Volatile organic compounds (VOCs).

Retention of Minerals

Carbon block filters not only filters the water but also retain all essential nutrients that exist in the water.

Also, it may add extra minerals like iron, magnesium, calcium, etc.

Ease of Use

Carbon block filters are very simple to manage.

In essence, there is practically no maintenance necessary.

Moreover, for every three months of usage, you may need to replace the filter.

This also depends on the average water intake.

Ease of Replacement

Replacing carbon block filters is simple.

Simply follow the user manual and you will have clean drinking water in no time.

There are several types of carbon block filters meaning you have a lot to choose from during replacement.


Carbon block filters are the most affordable filters on the market.

This is because the material occurs naturally.

Not only is this news good for your water, but it is also beneficial for your wallet.

Tasty Water

A natural filtration process leaves the flavor of water even stronger than it was.

Lots of people hate the flavor of tap water.

Carbon block filters adsorb harmful odors, making the water even more enticing.

Environmentally Friendly

By filling a reusable water bottle at home, you will end up saving a lot and help the environment in the long run.

On the other hand, buying water in a bottle will make you spend more and you will end up disposing of the bottle.

Try to imagine, one filter is equal to 300 bottles of plastic water.

Boost your Health

When you drink water that has undergone filtration, it provides a health benefit to your body.

This means your body will be free of diseases or infections that may come from dirty water.

Clean drinking water is important for your general wellbeing, from stomach problems to cancer.

Sustainable Resource Use

Carbon block filters do not need any extra energy or water pressure to operate.

Just a little bit of gravity is sometimes all it takes.

The water filters as it runs into the carbon block filter through to the other end, fresh and clear.


Several devices using a carbon filter are lightweight.

They make the ideal complement to a camping trip or a day out exploring in the wilderness.

Are you planning on taking a vacation?

You can easily bring a pitcher to your location, and breathe easy to know that your drinking water is clean.

How Does a Carbon Block Filter Compare to a Granular Activated Filter?

Here are some fundamental aspects you need to know:

Filtration Method

Carbon block filters will force water via a maze of carbon and then eliminates contaminants.

Granular activated filters have flow channels meaning water will easily bypass the filter.

Contact Duration

Water in carbon block filters spends a lot of time in contact with carbon.

On the other hand, there is less contact between water and granular activated carbon particles.

Filtration Efficiency

Carbon block filters will eliminate most of the contaminants in water thus more efficient.

However, granular activated carbon will remove only a few of the contaminants thus less efficient.


Both of these filters will filter out impurities out of the water making it clean and drinkable.

Design of the Filter

A granular activated filter comes from using ground carbon within a cartridge or container.

These granules form a loosely knit system.

On the other side, carbon block filters come from grinding activated carbon into a fine powder.

Thereafter, you will combine the powder with a food-grade binder.

Finally, you will heat and pack the mixture into a solid block.


It is expensive to manufacture carbon block filters.

On the other hand, it is affordable to manufacture granular activated filters.

How Does a Carbon Block Filter Operate?

There are three processes that a carbon block filter operates to eliminate contaminants from drinking water:

Mechanical Filtration

This method is similar to the working principle of a sieve.

Here, large contaminants that cannot pass through the pores will remain behind as water passes through the filter.

It is possible for carbon block filters to mechanically eliminate particles that have a size of one-half micron [submicron].

Electro Kinetic Adsorption

In this method, the carbon block filter uses a special outer wrap that is the electro kinetic adsorption.

Water will start by passing through this outer wrap.

In the meantime, material in the wrap will start acquiring a positive molecular charge.

This charge will bind on negative ions of some contaminants.

Physical Adsorption

In this process, the carbon block filter will attract the contaminants.

The large surface area of these filters will attract contaminants.

Also, there are special binders that will inhibit the masking on the surface of the carbon block filter.

This enhances its efficiency by lowering the level of contaminants in water.

What are the Water Purification Stages?

Here are the stages that water will undergo during the purification process:

Sediment Filtration

It is the first stage in the water purification process.

This stage eliminates most of the visible particles like silt, rust, dirt, and residue from pipes.

Pre-carbon Filtration

Here, the process will eliminate chlorine, pesticides, and chemicals from water.

RO/UF Membrane

This stage is responsible for eliminating all metals, solids, arsenic, etc. from water.

The RO filter size is 0.0001 micron while the UF filter size is 0.01 micron.

PH Filtration

Here, you will balance the acidity and alkalinity levels in the water.


This stage will eliminate all bacteria in the water.

Immune Detox

In this phase, you will add antioxidants.

Nutrient Boosting

Here, you will add minerals like magnesium and calcium.

Final Stage

In this stage, the final polish will add sparkle and a fresh taste.

water purification process

Water purification process

What Control Plans Does a Carbon Block Filter Adhere To?

The control plan will define the final carbon block filter.

It involves the product specification, mapping a plan from raw material acquisition, manufacturing, and inspection.

The control plan elements include:

Specifying the Final Product

Here, you will document the exact requirements of the final carbon block filter.

Some of these details include:

  1. Dimensions of the filter
  2. Capacity
  3. Contaminant removal efficiency levels, etc.

Testing and Evaluating the Methods

In this step, you will evaluate the attributes and type of tests during the production process.

Specification Limits

Here, you will record the allowable tolerances.

It enables you to guarantee that the final filter is within the parameters at every point of the process.

Control Location

In this stage, you will document the exact location where you did the tests.

Sampling Plans

Here, you will determine the statistical sample size concerning the production variables.

This ensures you collect data on each production step.

Reaction Plans

When the sample fails the evaluation test, you proceed by defining a clear guide that reacts to the results.

Evaluating and testing need extra attention.

Raw Material

Charcoal is a naturally occurring material.

There is considerable variability between sources of raw materials.

It is important to conduct a diverse sampling technique to acquire the best characteristics of carbon.

This influences how it will interact and perform in the production process.

The control plan will define the blending ratio of the raw materials.

Carbon Block Elements

The filter must meet all the specifications for it to work efficiently.

Some specifications you can measure include:

  1. Weight of the carbon block filter
  2. Length of the filter block
  3. Outside diameter [O.D.] of the filter
  4. Inside diameter [I.D.] of the filter
  5. Block porosity
  6. Permeability of the block
  7. Structural integrity

Final Filter

Several consumers want the complete carbon block filter.

Once you produce the filter, assemble it into a final product that one can start using immediately.

Extra specifications you can apply to the final product are:

  1. The flow rate of the filter
  2. Filter performance
  3. The dimension of wrap material
  4. Dimension of the end cap and the appeal


After you finish manufacturing the carbon block filter, you ship it to the consumers.

Also, user manuals are to accompany the filters.

What are the Types of Granular Activated Carbon?

There are two kinds of GAC filter systems and they are:

Point of Entry GAC

This system is at the main water supply unit.

It means water gets treatment before entering the housing unit.

Also, it eliminates contaminants before they get into the skin during washing or bathing.

Point of Use GAC

This filter system is at the water supply pipe where you will get water.

An example is an under-sink unit.

Here, water will pass via carbon filters and to another water tap.

Thereafter, it heads to the main faucet.

This water will undergo granular activated carbon treatment and that from the faucet will not undergo treatment.

Granular activated carbon

Granular activated carbon

Are all Carbon Block Filters the Same?

Activated carbon filters eliminate a high amount of contaminants than normal filters.

Also, some filters have a high amount of activated carbon than others.

This will affect the capacity of contaminants it can eliminate.

If you have a high number of activated carbon in filters, they will in turn eliminate more contaminants.

This is because they possess a faster and higher absorption rate.

Also, the more activated carbon a filter has, the longer its durability.

This means it needs fewer replacements yet they give out fresh water at all times.

The size of activated carbon filters will influence the filtration rate.

Besides, the smaller the particles, the higher the adsorption rate.

Some filters have additional compounds that can eliminate more hazardous contaminants.

Also, some are resilient to the buildup of bacteria thus increasing their lifespan.

What are the Types of Carbon Filters Present in the Market?

They include:

Granular Activated Carbon Filter

These particles in these filters are not compact.

This means water passes through them with ease.

Water will flow in one direction in the system as it contacts the carbon particles.

The advantage of this filter is that it is not restrictive as water flows through it quickly.

A disadvantage is that water can form channels thus allowing contaminants to flow through without filtration.

Carbon Block Filter

These have finer particles that bond together using a bonding agent.

The bonding agent occupies an average of 15% of its surface area.

Impure water flows via the side of the block then clean water leaves via the top area.

The finer the particles, the higher the surface area of the carbon block.

It has ten times more surface area than a granular activated carbon filter.

Also, its compact nature will prevent channeling from occurring.

Besides, the compact nature brings about a restrictive flow.

Radial Flow Granular Activated Carbon Filter

This filters the surface area of a carbon block filter and the rate of flow of granular activated carbon.

In this filter, water will flow into the filter via the sides of the cartridge like that of a carbon block filter.

Also, the rate of flow is high as it uses granular activated carbon mechanisms.

Are Carbon Block Filters Safe?

Yes, they are safe in addition to third-party ratings about their safety.

All of the carbon block filters have a CTO [Chlorine, Taste, Odor] rating.

This means it can eliminate these contaminants and some sub-micron filters will get rid of contaminants like cysts.

If a carbon block filter has a pore size of less than a micron, it will prevent cysts from passing.

What can Carbon Block Filter Remove?

Different carbon block filters come with different capabilities.

They can eliminate contaminants like:

  • Chlorine
  • Mercury
  • Lead
  • Bacteria
  • Pesticides
  • Herbicides
  • Bad taste
  • Foul odor
  • Trihalomethanes
  • Iron
  • Heavy metals

What are the Alternatives to Carbon Block Filters?

These are:

Carbon Filter Versus Sediment Filter

Sediment filters prevent dirt and debris from passing.

Carbon block filters can eliminate organic compounds that are responsible for bad taste and foul odor.

Sediment filters are mechanical filters that allow water to flow through and not contaminants larger than its micron rating.

Besides, carbon block filters cannot remove sediments but can remove particles through adsorption.

This means you require a sediment filter for this function.

Carbon Filter Versus Ceramic Filter

Ceramic filters are mechanical filters that can prevent some organic microorganisms from passing through.

One can enhance its efficiency by embedding carbon so that it can eliminate certain contaminants.

Incorporating carbon in ceramic filters enables it to remove chemicals and debris.

Carbon Filter Versus Reverse Osmosis

These two work in conjunction with one another.

Reverse osmosis will separate inorganic compounds and radionuclides that dissolve.

Chlorine can cause damage when it gets into contact with a reverse osmosis membrane.

For this reason, one incorporates a carbon filter to eliminate this damage.

Carbon filtration makes part of reverse osmosis at some stages in the water filtration process.

How long Does a Carbon Block Filter Last?

It is important to change carbon block filters after six months to a year.

Some only last for two to three months.

Not changing it does more bad than good as it can make the water even worse.

When the pores are full, the particles can start to break away and flow in the water.

How Does Compressed and Extruded Carbon Block Manufacturing Processes Compare?

Extrusion or using compression molding are the two processes that can manufacture carbon blocks.

Manufacturing extruded carbon blocks require a combination of carbon, binders, and some media materials.

One will force these media materials via a die which will form a continuous block.

Thereafter, you will trim the block to a sizeable chunk.

Also, you will manufacture compressed carbon block in molds under extreme pressures and high temperatures.

After that, you will also trim them to their sizes.

Using compression molding will require additional manufacturing labor at a low production rate.

Besides, compression molding makes the final product have a consistent filtration mechanism.

One can use different kinds of binders when making compression molding than extrusion moldings.

Compression moldings also require fewer binders than extrusion moldings.

Also, compression carbon blocks offer more variation in types of shapes thus adding extra design flexibility.

compressed and extruded carbon block

Compressed and extruded carbon blocks

What are The Carbon Block Filter Design Parameters?

These are:

Raw Materials

Different raw materials can make carbon block filters.

Some common sources of carbon include nutshells, wood, and bituminous coal.

Bituminous coal is cheap and in plenty.

Besides, coal-based carbon contains contaminants that can leach from water.

Wood-based carbon can lower certain contaminants.

It is a renewable, readily available source.

Nutshells that come from coconuts are the best when it comes to making filters for drinking water.

Coconut shell carbon contains several microspores that are porous and increase the surface area.

Also, activated coconut shell carbon has 50% extra microspores than bituminous coal carbon.

This means coconut shell carbon adsorbs more small molecules like VOCs.

The advantage of coconut shell carbon is that it is pure and thus enhances quality control.

Also, it is a renewable green source.

Filter Performance

One objective to consider is the target capacity of these filters.

The capacity is the number of liters the filter can handle before needing replacement.

Flow rate is the number of liters it can continuously filter per minute.

Also, pressure, which you measure in pounds per square inch [psi] is another vital parameter that determines performance.

Pore size will indicate the micron rating which is the smallest particle size it can mechanically filter out.

Contaminant reduction specifies the contaminants it can acceptably eliminate following treatment.

Performance Validation

One can perform this test in the laboratory with NSF standards and American National Standards Institute (ANSI).

NSF standards check the reduction of contaminants to lower than Maximum Contaminant Level (MCL).

Underwriters Laboratory (UL) and Water Quality Association (WQA) are some bodies that adopt NSF/ANSI test parameters.

For instance, standard 42 and 53 within NSF/ANSI highlights the following:

  1. Consistent manufacturing process.
  2. If the filter will add harmful elements to water.
  3. Accurate and truthful texts and labels on the product.
  4. Sound pressure vessel under extreme operating conditions.

Filter Configuration and Finish

This is the external, internal, and length of the filter.

Thickness is the difference between the outside and inside diameter and determines the contact time of water and carbon.

End caps will determine the force water goes through the carbon and the seals.

The outer wrap assists in pre-filtration and enhances the appeal of the filter.

Inner wrap prevents carbon fines from flowing with the final clean water.

Also, the housing should sustain the working condition of the filter.

Performance Indication

A Performance Indication Device [PID] assists consumers when it comes to maintaining the unit.

PIDs will measure water usage thus inform users when it is time to replace the filter.

NSF standard stipulates that the claims should not be more than 50% of the test capacity.

When using a PID, NSF allows the claim to be 80% of the test capacity.

PIDs provide more filter utilization and manage costs while making sure the filter remains within the design limits.

carbon block filter design

Carbon block filter design

What are the Advantages of a Custom Carbon Block Filter?

These filters have several advantages.

They can add flexibility when it comes to designing the housing unit.

This means you can adapt it to the environment depending on the water condition available.

Also, you can optimize it for certain performances and in the reduction of contaminants.

It will allow consumers to have more options when selecting raw materials.

Besides, it provides manufacturers with control when it comes to designing the final product.

It also gives control when it comes to revenue that comes from the replacement of filters.

Customization also gives exclusivity when it comes to the replacement of filters in the business.

Why is it Important to Certify a Carbon Block Filter?

Some manufacturers of carbon block filters may exaggerate their units.

This may mean that the lifespan, filtration rate, and effectiveness do not match up.

They may indicate that their filters offer a 99% reduction of lead or 95% elimination of chlorine which may be false.

The Water Quality Association [WQA] and NSF international assist with certifying these devices.

They will test these filters and their components.

After approval, they place their logos on carbon block filters to assure their quality.

NSF international will certify that a carbon block filter will eliminate certain contaminants.

When NSF certifies a carbon block filter, it means that:

  • It has a solid structure
  • The material construction is durable.
  • Also, it contains plastics and parts that will not leak into the water I.e. BPA.
  • Besides, the test results are 100% accurate.
  • The labels are 100% correct.

NSF certificates may approve some parts or the contaminants that it can minimize.

Some NSF certifications available include:

NSF Standard 53

This ensures the carbon block filter will reduce specific toxic elements.

These contaminants are:

  1. Lead
  2. Giardia
  3. Methyl Tertiary Butyl Ether (MTBE)
  4. Cryptosporidium
  5. Volatile Organic Compounds (VOCs)

The safety standards include structural principles, reduction of contaminants, and safe materials.

NSF Standard P473: PFOA/PFOS

This certifies the reduction of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate.

NSF Standard 58

This also is a safety standard relating to lead and other contaminants.

It looks at filters that use membranes such as reverse osmosis [RO].

NSF Standard P231

This will certify the removal of contaminants such as bacteria and viruses.

NSF Standard 42

This standard certifies the ability of carbon block filters to eliminate chlorine.

NSF/ANSI 42, 53, and 401 describe the aesthetic effects of these systems.

This standard excludes harmful by-products of chlorine

It indicates that these filters can remove:

  1. Chlorine
  2. Particulates
  3. Taste
  4. Odor
  5. Iron
  6. Zinc
  7. Manganese
  8. Total dissolved solids [TDS]

NSF Standard 401

This is a new standard that highlights the ability of these filters to minimize up to 15 various contaminants.

Also, it applies to carbon and reverse osmosis water filters.

It combats unnatural chemicals such as:

  1. BPA
  2. Pharmaceuticals
  3. Pesticides
  4. Herbicides

Can a Carbon Block Filter Remove Bacteria?

It will only trap the bacteria but cannot kill them.

A reverse osmosis filter is the only system that can eliminate bacteria.

One can eliminate bacteria from water by using chlorine or UV rays.

How can You Reactivate a Carbon Block Filter?

It is possible to reactivate this filter once they are full of impurities die to adsorption.

However, it requires one to heat the carbon at high temperatures of up to 900 0C.

Also, when you reactivate it, you will be releasing all the impurities that were in it.

These pollutants are toxic at these high-temperature levels.

As a caution, reactivation occurs inside an inert gas chamber.

What are the Physical Properties of an Activated Carbon Block Filter?

They are:


Hard and dense coconut-shell carbon makes it last for several months.

Ash Content

Ash content in coal and wood-based carbon varies between 10% and 15%.

In coconut-based filters, this ranges between 3% and 5%.

Ash will reduce the performance of the activated carbon.

Also, lower ash content makes the carbon block filter better.

Hardness and Density

Coconut-based filters contain a high density.

This provides a large area for filtration to take place.

Also, it is resistant thus protects attrition.

activated carbon block filter

Activated carbon block filter

How Can You Select the Best Carbon Block Filter?

The process involves the following:

  • Ensure the source of carbon is coconut
  • Examine the block externally
  • Review the performance metrics
  • Inquire about the iodine value
  • Examine quality certifications

How Frequent Can You Backwash Carbon Block Filters?

Chlorine is a good material for disinfecting water.

However, several people prefer to use non-chlorinated water when showering as it may irritate.

This is because they may be allergic to chlorine or they have sensitive skins.

Backwashing is the process of eliminating chlorine and sediments up to the size of 30 microns.

This backwash carbon filter has canisters with activated carbon media.

The activated carbon will eliminate chlorine via a chemical process that oxidizes the surface of the carbon.

During backwash, the carbon undergoes cleaning between 6 to 8 minutes and a rinse cycle time of 4 to 6 minutes.

Backwashing normally happens once a day normally in the middle of the night.

Can a Carbon Block Filter Lower pH?

It may absorb carbon dioxide which may increase the ph.

This filter has minimal effect on the pH value.

Can a carbon Block Filter Eliminate Unpleasant Smell?

Yes, it can assist in eliminating the bad smell.

There is some activated carbon that works with HEPA filters that can eliminate 99.9% of particles.

Virgin activated carbon is suitable for eliminating foul odor, pollutants, and VOCs.

This happens through absorption and adsorption.

How Can You Clean a Carbon Block Filter?

Ensure you clean it in a place with proper ventilation as you will use chemicals.

Wear gloves to protect your skin and wear a mask or goggles.

Fill a bucket with room temperature, half a gallon of clean water.

Gently add two cups of muriatic acid.

Stir carefully using a plastic stirrer.

Rinse off visible debris out of the filter using clean water and a pressurized hose.

After that, place it inside the solution.

Allow the filter to remain in the solution for at least five days.

Make sure the solution is at room temperature during this entire period.

Afterward, soak the filter in clean water for five minutes.

Rinse the filter with a hose.

Thereafter, reinstall it in place.

In short, before sourcing for carbon block filters, you should consider all information highlighted here.

However, in case you have any questions or inquiry, feel free to contact FilSon Filters team.