CARBON FILTRATION (See Products)
Carbon Filtration stand alone
Carbon block or Carbon Granular Activated Filters can be configured as part of an RO system or a UV system, or can stand alone for removal of chlorine, taste and odor (as in our Single and Dual Filter Assemblies, available at USPW.)
Carbon Block removes gaseous and low weight molecules such as chlorine, herbicides, pesticides and VOC's. As water is forced through the micro pores of the carbon filter, organics in the water adhere, or "hang on" to (or molecularly bond with) the carbon. This is known as "adsorption". Activated carbon has earned a name for its effectiveness in reducing chlorine and low molecular weight organics (VOCs), such as THMs, TCE, pesticides and herbicides and other chemicals found in industrial waste. Carbon also virtually eliminates bad taste and odor. Because carbon reduces light weight gaseous volatile chemicals (which are some of the most toxic), and not heavier weight contaminants (minerals and metals) we call this partial spectrum treatment.
Our carbon filter is manufactured using a method of extrusion that allows the free formation of the carbon in a highly uniform fashion. Because of the excellent porosity, permeability and uniformity of the media in these filters, contact with the media is assured, allowing a very thorough adsorption of chlorine, THM's, TCE, vinyl chloride, carbon tetrachloride, bad tastes and odors, pesticides, herbicides, VOCs (volatile organic chemicals), and more. As these molecules are some of the most toxic of the chemical contaminants found in tap water AND they are not removed by reverse osmosis (the molecules are too small to be removed by the straining action of the ultra filtration feature, and due to their light weight they are not repelled by the selective permeability feature of the membrane), it is important that carbon filtration be used in conjunction with reverse osmosis. The pore size of the carbon block filter is available in a range of 10 micron to sub-micron depending on your system and your needs.
Carbon Filtration combined with Reverse Osmosis
Because Reverse Osmosis does not thoroughly remove the lighter, low molecular weight volatile organics such as THM's, TCE, chlorine and it's by products, (they are too small to be removed by the straining action of the ultrafiltration ability of the membrane and not chemically suitable to be repelled by the membrane surface), it is important they be removed by a carbon filter added to the RO system. Combining RO and carbon filtration in a soundly designed purification system, compliments & enhances the actions of both and is an ideal formula for removing the entire spectrum of contaminants.
Carbon Block Filters vs. GAC ~ Granular Activated Carbon
Activated Carbon Filtration
Made from a variety of carbon based materials such as coal, petroleum, nut shells and fruit pits.
Activated carbon has been found extremely effective in and is the industry standard for reducing/removing organic chemicals, including chlorine, pesticides, industrial chemicals, THM's, PCB's and other similar halogenated organic compounds, as well as bad taste & odor.
Can be POE or POU; When used as POE it is effective at removing chlorine and many tastes and odors from household water. Recently, because of concern over health effects from inhaling toxic organic chemicals found in shower water etc. there is interest in more effective POE carbon treatment systems. When used as POU there is a vast range of types of systems and degrees of effectiveness.
Lower quality ones remove only chlorine, tastes and odors for a short time. High quality ones remove this plus a wide range of toxic organic chemicals (VOCs). Chlorine is easier to "hold on to" than VOCs, so if the manufacturer takes shortcuts on the processing or amount of carbon in the filter, the filter will not grab the VOCs, or will grab them initially, then let them go in favor of incoming chlorine.
Granular Activated Carbon (GAC)
Granular activated carbon is a form of charcoal that has been treated by high temperatures and steam in the absence of oxygen. This process produces small granules that are extremely porous with a high surface area. GAC filters remove organics from the water by holding them to its surface, a process known as adsorption. As water passes around each little particle of carbon, the organics adhere to the particles. One pound of granular activated carbon has a total surface area of about 125 acres, giving each filter the ability to handle large amounts of water before becoming "used up". When GAC is used in a tall column, most of the unwanted organic pollutants are adsorbed in the top layers, and as the water passes downward it progressively contacts cleaner and cleaner carbon. This in depth filtering "polishes" the water as it passes out of the column and provides a wide margin of organic removal.
While a wide variety of filters are made of GAC, not all will perform equally. Effectiveness varies with the kind of carbon used in the filter, the filter design, the way it is used and maintained, its age, and the condition of the water being treated.
Carbon Block Filters
Also referred to as Extruded Activated Carbon (EAC) or Compressed Carbon, very fine pulverized carbon is compressed and fused together with a bonding media. The intricate maze developed within the block insures contact with organic impurities.
Our carbon filters is manufactured using a method of extrusion that allows the free formation of porous solids (in this case, carbon) in a highly uniform fashion. Because extruded activated carbon parts are produced on a single tool rather than open large numbers of individual molds, dimensional uniformity of each piece is exceptional. Uniformity, strength, porosity, permeability, adsorbent capacity, and dimension accuracy are a few of the advantages to this technology.
Unlike the GAC carbon filter, where water flows around the carbon particles, the carbon block forces water to penetrate through it. This allows for a more complete contact with and subsequent adsorption of chlorine, THM's, bad tastes and odors, toxic metals, and more. The pore size of the carbon block filter is variable, and is usually available in a range of 10 micron to sub-micron (@.4). When used in tandem, usually with a 10 micron first and a sub-micron second, these filters can provide the most complete removal of organic matter available.
As with GAC filters, EAC filters do become "used up" as well, and should be replaced regularly.
Silver Impregnated Carbon
Also called Bacteriostatic or Oligodynamic carbon-Some manufacturers coat the surface of carbon granules w/ silver compounds which are supposed to inhibit the growth of bacteria within the carbon bed. Because silver is consi-dered a toxin these filters must be registered under the Federal Insecticide, Fungicide and Rodenticide Act. EPA sponsored testing of such filters have shown that they are "neither effective nor dependable in meeting their claims".
Limitations
The only real drawback associated with carbon filters is that they can grow bacteria and harbor other (usually harmless) matter on the carbon surface. The risk is that over time, this matter can break off and contaminate the water, defeating the whole purpose of water treatment. The carbon can also become "used up" as the adsorption of organic molecules saturates the media. Determining factors for the amount of time this takes are water temperature, sediment content, chlorine levels, organic chemical levels, and total amount of water treated.
Carbon filters will not remove dissolved solids, fluorides, heavy metals or mineral salts. If complete water purification is desired, the removal of these items can only be attained through reverse osmosis, de ionization or distillation.
One of the drawbacks of a GAC filter is its tendency to "channel", where water creates distinct paths through the media. This greatly reduces the available contact area, which shortens the effective life of the filter. It also means that additional prefiltering becomes necessary because the carbon is not at a uniform pore size for this purpose.
Filter Replacement
As mentioned, GAC and EAC cartridges should be replaced on a regular basis. Some determining factors for replacement time are water conditions and temperature, number of gallons treated, chlorine and other organic chemical content of the feed water, sediment and turbidity. For average household usage, depending on the size and type of the carbon filter combined with the family size and the factors listed above, expect to change out the filter every 2-6 months. For industrial and commercial use, every 2 weeks to 6 months, depending on the application. The replacement cost of carbon block filters is usually higher than GAC filters. Prices will vary, as will quality, and the two do not always go hand in hand. When you purchase a filter system, check with your dealer for the manufacturer's recommendations.
oCarbon block is more effective than Granular carbon for VOC adsorption for the same length of contact time. It is easier for the carbon to adsorb chlorine than VOCs. Important to have high quality filters.
RO/Filtration Combo
Our systems utilize a proven combination of reverse osmosis and carbon filtration. Nothing could be better for effective carbon filter absorption than having an RO membrane prior to it to remove practically all of the contaminants which would gradually impair the carbon's performance. RO & Carbon Block complement each other in their capacity for contaminant reduction, the combination of which removes the broadest spectrum of contaminants. At this time there is a very broad variation in the design and quality of RO. Configuration and quality of parts can determine whether unit is effective. (See 'Technical/RO Configurations')
Carbon block or Carbon Granular Activated Filters can be configured as part of an RO system or a UV system, or can stand alone for removal of chlorine, taste and odor (as in our Single and Dual Filter Assemblies, available at USPW.)
Carbon Block removes gaseous and low weight molecules such as chlorine, herbicides, pesticides and VOC's. As water is forced through the micro pores of the carbon filter, organics in the water adhere, or "hang on" to (or molecularly bond with) the carbon. This is known as "adsorption". Activated carbon has earned a name for its effectiveness in reducing chlorine and low molecular weight organics (VOCs), such as THMs, TCE, pesticides and herbicides and other chemicals found in industrial waste. Carbon also virtually eliminates bad taste and odor. Because carbon reduces light weight gaseous volatile chemicals (which are some of the most toxic), and not heavier weight contaminants (minerals and metals) we call this partial spectrum treatment.
Our carbon filter is manufactured using a method of extrusion that allows the free formation of the carbon in a highly uniform fashion. Because of the excellent porosity, permeability and uniformity of the media in these filters, contact with the media is assured, allowing a very thorough adsorption of chlorine, THM's, TCE, vinyl chloride, carbon tetrachloride, bad tastes and odors, pesticides, herbicides, VOCs (volatile organic chemicals), and more. As these molecules are some of the most toxic of the chemical contaminants found in tap water AND they are not removed by reverse osmosis (the molecules are too small to be removed by the straining action of the ultra filtration feature, and due to their light weight they are not repelled by the selective permeability feature of the membrane), it is important that carbon filtration be used in conjunction with reverse osmosis. The pore size of the carbon block filter is available in a range of 10 micron to sub-micron depending on your system and your needs.
Carbon Filtration combined with Reverse Osmosis
Because Reverse Osmosis does not thoroughly remove the lighter, low molecular weight volatile organics such as THM's, TCE, chlorine and it's by products, (they are too small to be removed by the straining action of the ultrafiltration ability of the membrane and not chemically suitable to be repelled by the membrane surface), it is important they be removed by a carbon filter added to the RO system. Combining RO and carbon filtration in a soundly designed purification system, compliments & enhances the actions of both and is an ideal formula for removing the entire spectrum of contaminants.
Carbon Block Filters vs. GAC ~ Granular Activated Carbon
Activated Carbon Filtration
Made from a variety of carbon based materials such as coal, petroleum, nut shells and fruit pits.
Activated carbon has been found extremely effective in and is the industry standard for reducing/removing organic chemicals, including chlorine, pesticides, industrial chemicals, THM's, PCB's and other similar halogenated organic compounds, as well as bad taste & odor.
Can be POE or POU; When used as POE it is effective at removing chlorine and many tastes and odors from household water. Recently, because of concern over health effects from inhaling toxic organic chemicals found in shower water etc. there is interest in more effective POE carbon treatment systems. When used as POU there is a vast range of types of systems and degrees of effectiveness.
Lower quality ones remove only chlorine, tastes and odors for a short time. High quality ones remove this plus a wide range of toxic organic chemicals (VOCs). Chlorine is easier to "hold on to" than VOCs, so if the manufacturer takes shortcuts on the processing or amount of carbon in the filter, the filter will not grab the VOCs, or will grab them initially, then let them go in favor of incoming chlorine.
Granular Activated Carbon (GAC)
Granular activated carbon is a form of charcoal that has been treated by high temperatures and steam in the absence of oxygen. This process produces small granules that are extremely porous with a high surface area. GAC filters remove organics from the water by holding them to its surface, a process known as adsorption. As water passes around each little particle of carbon, the organics adhere to the particles. One pound of granular activated carbon has a total surface area of about 125 acres, giving each filter the ability to handle large amounts of water before becoming "used up". When GAC is used in a tall column, most of the unwanted organic pollutants are adsorbed in the top layers, and as the water passes downward it progressively contacts cleaner and cleaner carbon. This in depth filtering "polishes" the water as it passes out of the column and provides a wide margin of organic removal.
While a wide variety of filters are made of GAC, not all will perform equally. Effectiveness varies with the kind of carbon used in the filter, the filter design, the way it is used and maintained, its age, and the condition of the water being treated.
Carbon Block Filters
Also referred to as Extruded Activated Carbon (EAC) or Compressed Carbon, very fine pulverized carbon is compressed and fused together with a bonding media. The intricate maze developed within the block insures contact with organic impurities.
Our carbon filters is manufactured using a method of extrusion that allows the free formation of porous solids (in this case, carbon) in a highly uniform fashion. Because extruded activated carbon parts are produced on a single tool rather than open large numbers of individual molds, dimensional uniformity of each piece is exceptional. Uniformity, strength, porosity, permeability, adsorbent capacity, and dimension accuracy are a few of the advantages to this technology.
Unlike the GAC carbon filter, where water flows around the carbon particles, the carbon block forces water to penetrate through it. This allows for a more complete contact with and subsequent adsorption of chlorine, THM's, bad tastes and odors, toxic metals, and more. The pore size of the carbon block filter is variable, and is usually available in a range of 10 micron to sub-micron (@.4). When used in tandem, usually with a 10 micron first and a sub-micron second, these filters can provide the most complete removal of organic matter available.
As with GAC filters, EAC filters do become "used up" as well, and should be replaced regularly.
Silver Impregnated Carbon
Also called Bacteriostatic or Oligodynamic carbon-Some manufacturers coat the surface of carbon granules w/ silver compounds which are supposed to inhibit the growth of bacteria within the carbon bed. Because silver is consi-dered a toxin these filters must be registered under the Federal Insecticide, Fungicide and Rodenticide Act. EPA sponsored testing of such filters have shown that they are "neither effective nor dependable in meeting their claims".
Limitations
The only real drawback associated with carbon filters is that they can grow bacteria and harbor other (usually harmless) matter on the carbon surface. The risk is that over time, this matter can break off and contaminate the water, defeating the whole purpose of water treatment. The carbon can also become "used up" as the adsorption of organic molecules saturates the media. Determining factors for the amount of time this takes are water temperature, sediment content, chlorine levels, organic chemical levels, and total amount of water treated.
Carbon filters will not remove dissolved solids, fluorides, heavy metals or mineral salts. If complete water purification is desired, the removal of these items can only be attained through reverse osmosis, de ionization or distillation.
One of the drawbacks of a GAC filter is its tendency to "channel", where water creates distinct paths through the media. This greatly reduces the available contact area, which shortens the effective life of the filter. It also means that additional prefiltering becomes necessary because the carbon is not at a uniform pore size for this purpose.
Filter Replacement
As mentioned, GAC and EAC cartridges should be replaced on a regular basis. Some determining factors for replacement time are water conditions and temperature, number of gallons treated, chlorine and other organic chemical content of the feed water, sediment and turbidity. For average household usage, depending on the size and type of the carbon filter combined with the family size and the factors listed above, expect to change out the filter every 2-6 months. For industrial and commercial use, every 2 weeks to 6 months, depending on the application. The replacement cost of carbon block filters is usually higher than GAC filters. Prices will vary, as will quality, and the two do not always go hand in hand. When you purchase a filter system, check with your dealer for the manufacturer's recommendations.
oCarbon block is more effective than Granular carbon for VOC adsorption for the same length of contact time. It is easier for the carbon to adsorb chlorine than VOCs. Important to have high quality filters.
RO/Filtration Combo
Our systems utilize a proven combination of reverse osmosis and carbon filtration. Nothing could be better for effective carbon filter absorption than having an RO membrane prior to it to remove practically all of the contaminants which would gradually impair the carbon's performance. RO & Carbon Block complement each other in their capacity for contaminant reduction, the combination of which removes the broadest spectrum of contaminants. At this time there is a very broad variation in the design and quality of RO. Configuration and quality of parts can determine whether unit is effective. (See 'Technical/RO Configurations')