Choosing an activated carbon filter for liquid filtration typically offers two options: carbon block and granular activated carbon (GAC). In a carbon block filter, the carbon is ground into a fine powder and is compressed to form a solid block. A granular carbon filter, on the other hand, is made up of loose granules of carbon. The compact nature of solid carbon provides better purification whereas the looser nature of GAC provides a higher flow rate.
Both carbon block and GAC filters are made of activated charcoal. Carbon-based filters filter contaminants through absorption. They play a significant role in removing components like trihalomethanes (THMs), solvents, gasoline, pesticides, industrial cleaners, and chlorine. Carbon filters also play a role in improving the odor and taste of the water.
This article discusses three critical points of distinction between a carbon block filter and a granulated carbon filter.
Filter Design
Carbon block filters are made of carbon that is ground into smaller sizes. This powder is then blended with a food-grade binder. The resulting combination is converted into a solid block through heat and compression. The compact nature of carbon block requires more time for the water to flow through the filter.
Granular block filters are made of small, loose granules of carbon that are held together within a filter housing. The size of carbon in GAC filters is typically 5 to 20 times larger than that of carbon block filters. The loose granules of carbon in GAC filters allow the water to flow easily through the filter channel.
Filter Effectiveness
Carbon block filters come with a larger surface area because they contain more carbon particles than GAC filters. Their compact nature allows them to absorb more contaminants and remove the minutest particles, heavy metals, and other contaminants from the water. The filtration process can be slower since the water is required to force through the tightly packed carbon particles. As a result, carbon block filters have a longer contact time with water. Factors like lower flow rate, more contact time, and the compact nature of carbon block filters help them achieve maximum filtration efficiency.
Granulated carbon filters are more loosely packed. Due to a lower surface area, GAC filters are less effective in filtering contaminants. Since the water flows much faster through loose granules, there is a lower contact time between the water and the filter. This causes the filter’s absorbability to decline while the high flow rate remains intact. As a result, GAC proves less effective in terms of contamination removal when compared to carbon block filters. Although they have a lower purification rate, GAC filters have the capacity to last longer than carbon block filters.
Filter Costs
Carbon block filters go through time-consuming manufacturing processes that make them more expensive. However, these filters are the best choice when it comes to achieving a near-perfect filtration efficiency.
Granulated carbon filters, on the other hand, come with lower manufacturing costs which makes them a cheaper option.
Conclusion
Aside from the fact that both a carbon block filter and a granular carbon filter are made from ground-activated charcoal, they offer distinct filtration capabilities. Many water purification systems make use of both filters based on the different stages of filtration. Ultimately, buying the right filter comes down to what the filtration requirement is: higher purification or higher flow rate.
Regardless of the type of filter that is needed, it’s critical to note that both filters need timely replacement. Carbon media can be a breeding ground for bacteria. When the liquid leaves behind too many contaminants, it gets easier for bacteria to replicate. For this reason, individuals handling the system must ensure the water goes through a thorough pre-treatment process before passing through the filter.
Specific water sources require specific carbon filters. The filter needed for a municipal water source, for instance, might not be the best fit for water sourced from a well. If unsure about the right filter choice, the best approach would be to seek the help of a professional. Commercial Filtration Supply offers a variety of carbon block and GAC filters that are high-performing and economical. We have a team of experienced specialists to help select the right filter for your company's needs. Contact us today for a quote!