Solid Carbon Block Filters
This technology has combined the incredible adsorption capability of carbon discussed previously with the ability of a solid brick of material to selectively strain out particles from water forced through it. The density of the brick determines how finely the water is cleaned. The better brands of this type of filter have a three part filter and are designed to prevent any possibility of "bypass" due to high pressure failure.
The following list of features are what combine to create the type of filter that will remove the widest range of possible contaminants in the drinking water:
Mechanical straining: the block of carbon mechanically strains out dirt, sediment, rust, algae, bacteria, microscopic worms, cryptosporidia and asbestos. This is all accomplished by water pressure so no electricity is required -- such a filter even works on a simple hand pump in emergencies!
Chemical bonding: As explained earlier, activated carbon bonds to thousands of chemicals. In fact, carbon will bond to most chemicals known to man! When water is forced through the solid carbon block, it is forced to slow down and increase the contact time with the carbon, allowing the carbon bonding to take place to remove the chemical pollutants like toxics, pesticides, THM's, chlorine, bad tastes, odors, etc.
Health-providing trace minerals like dissolved calcium and magnesium do not bond to carbon and are allowed to pass through, thereby retaining the health quality and good taste of the water.
Heavy metals like lead do not bond to the carbon, but are strained out by the pore size of the block -- basically like trying to fit a basketball down a hole designed for a ping pong ball!!
Prevention of bacterial growth: Bacteria are strained out and remain on the outside of the carbon block. Therefore, because of the density and lack of oxygen and space inside the block, bacteria cannot breed in the medium and come out in the finished water.
Convenient: This type of system provides purified water on demand so there is no storage, nor running out at inconvenient times, no ordering bottles or picking bottles up from the store.
Inexpensive: This type of filter is a replaceable, self-clogging cartridge that lasts eight to 12 months (dependent on amount of sediment and dirt). The cartridge is designed to be replaced in minutes at home by the homeowner, just like screwing in a new light bulb. The cost of the units are relatively inexpensive -- over a ten-year period, the cost of the unit plus maintenance works out to a mere sixty bucks a year!! The cost of the water itself is from four to 8 cents per gallon. The units themselves are generally very easy to install and are designed to be a 45 minute installation for the handy homeowner or plumber. They can also be connected with refrigerators that have automatic icemakers and water dispensers so that all the water that a household consumes is purified!
The only drawback to solid carbon block systems is they will not remove nitrates or sulfides (byproducts of agricultural fertilization), and in these cases RO technology can take care of the problem. Nitrates and sulfides are found in relatively few areas however, so most consumers do not need to worry about them.
Salute!
