Carbon Block filters can be fabricated by molding or extruding a mixture of activated carbon, other special adsorbents, filter aids, and binders into a stable, unmovable structure of nearly any size, shape and porosity with a variety of possible claims. Since the grains of media are held in place by binders, carbon blocks are much less susceptible to hydraulic failure due to channeling and dumping than ordinary granular media. However, that also assures that they cannot avoid total clogging, eventually. The thickness of blocks allows the entrapment and adsorption mechanisms of depth filtration to dominate the removal of fine particles, so that they often achieve considerably greater hydraulic capacity than that predicted by their filtration surface area and the hydraulic equations discussed above. Thus, the 30 : 1 theoretical advantage of precoat filters noted in the previous paragraph should be revised to some lesser factor, say, 15-20 : 1. Carbon block filters can also have excellent adsorptive ability and capacity, since they may contain large amounts of media, sometimes exceeding that of GAC filters of the same size. Thus, unlike precoat filters, they have significant capacity for reduction of “combined chlorine” (monochloramine) and VOCs (Volatile Organic Chemicals) such as THMs and industrial solvents, and it is a simple matter to include special adsorbents for heavy metals in the media mixture.