Technical Talk: Activated Carbon vs. Carbon Block

I wanted to take a look at point of use drinking water filters. A standard filter housing is compatible with hundreds of 10 inch replacement filter cartridges so you have a lot of options on what to use.

Carbon based filters rely on activated carbon to remove impurities from water. Activated carbon filters attract dissolved chemicals causing them to stick to the carbon surface as the water passes through the filter. This is often referred to as the adsorption process and effectively removes chlorine, particles and volatile organic chemicals (VOCs).

So when it comes to drinking water you should definitely use a carbon based filter cartridge to remove chlorine and other chemical contaminants. Carbon filters come in two types, granular activated filters (GAC) and extruded carbon block filters.

GAC filters have a porous structure allowing for a wide surface area and are best for slower flow rates to allow for more contact time with the filter media. GAC filters are often used for large scale filtration because it is cheaper while still having effective contaminant reduction.

Extruded carbon block filters are made by taking activated carbon and grinding it into a very fine dust before reforming it into a solid carbon block. Carbon block filters are stronger than GAC filters and will not collapse under pressure change. This means that a carbon block filter will not allow changes in water pressure to create channels where water can pass through unfiltered. Carbon block filters are the best choice for point of use drinking water filters due to their ability to remove contaminants more consistently throughout the life of the filter.