Dual Whole House Water Filtration 1.5 CU FT OF GRANULAR ACTIVATED CARBON:
Carbon is a substance that has a long history of being used to absorb impurities and is perhaps the most powerful absorbent known to man. One pound of carbon contains a surface area of roughly 125 acres and can absorb literally thousands of different chemicals. Activated carbon which has a slight electro-positive charge added to it, making it even more attractive to chemicals and impurities. As the water passes over the positively charged carbon surface, the negative ions of the of the contaminants are drawn to the surface of the carbon granules. Activated carbon filters used for home water treatment typically contain either granular activated carbon or powdered block carbon. Although both are effective, carbon block filters generally have a higher contaminant removal ratio. The two most important factors affecting the efficiency of activated carbon filtration are the amount of carbon in the unit and the amount of time the contaminant spends in contact with it. The more carbon the better. Similarly, the lower the flow rate of the water, the more time contaminants will be in contact with the carbon, and the more absorption that will take place. Particle size also affects removal rates. The most common carbon types used in water filtration are bituminous, wood, and coconut shell carbons. While coconut shell carbon typically costs 20% more than the others, it is generally regarded as the most effective of the three. All of our activated carbon filters use coconut shell carbon. There are two principal mechanisms by which activated carbon removes contaminants from water; absorption, and catalytic reduction, a process involving the attraction of negatively-charged contaminants ions to the positively-charged activated carbon. Organic compounds are removed by absorption and residual disinfectants such as chlorine and chloramines are removed by catalytic reduction. Activated carbon filtration is very common in a number of home water treatment systems. It can be used as a stand alone filter to reduce or eliminate bad tastes and odors, chlorine, and many organic contaminants in municipal (pre-treated or chlorinated) water supplies to produce a significantly improved drinking water. Activated carbon filters remove/reduce many volatile organic chemicals (VOC), pesticides and herbicides, as well as chlorine, benzene, trihalomethane (THM) compounds, radon, solvents and hundreds of other man-made chemicals found in tap water.
1.5 CuFt. Catalytic Carbon
One of the key characteristics of activated carbon is not only the high surface area available relative to their mass, but also the ability to act as a substrate for other materials. Internal surface area in the range of 850-2000m2/g allows the concentrated loading of highly specialized reagents (for example platinum and rhodium for hydrogenation processes) to the carbon surface that can be used in synthesis and catalysis applications across a range of industries. Activated carbons Carbons are carefully engineered to have the correct physical properties to optimize their use in this duty, manufactured from coconut shell, coal or wood bases.
Many water utilities across the U.S. are transitioning to chloramine for disinfection as an alternative to chlorine. This change is in response to stricter U.S. Environmental Protection Agency regulations on disinfection byproducts (DBPs), which are created when chlorine reacts with organics in water. Chloramine, a combination of chlorine and ammonia, is more stable and does not create DPBs.
Removing chloramine at the point of use, however, is more difficult than removing chlorine. Standard granular activated carbon (GAC) and carbon gac products have limited capacity for chloramine reduction. Products known as “catalytic” or “surface-modified” activated carbon can provide a solution.
In general, the catalytic properties of carbon are measured by the rate at which carbon decomposes hydrogen peroxide. The resulting peroxide number, measured in minutes, estimates the carbon’s utility in any catalytic application, including chloramine reduction. Based on the comparative results obtained for different mesh size commercial carbons, the efficiency of chloramine reduction is discussed in the terms of peroxide decomposition capacity and further extended to the total life (volume) claims for corresponding GAC carbon.
Chemistry of Iron Oxidation:
A mineral found in soil, iron normally exists in an insoluble oxide form, namely ferric oxide. If acidic ~ or carbon dioxide ~ containing water passes through the soil, the insoluble ferric oxide is reduced to the very soluble ferrous form. When water is pumped from the ground, oxygen from air enters the water and is available for reaction with the ferrous iron. In the presence of oxygen the ferrous form is eventually oxidized to the insoluble ferric form, resulting in familiar red deposits that stain sinks and clothes.
Under normal conditions, the reaction rate of ferrous to ferric iron is fairly slow, even when excess oxygen is present. This slow reaction rate necessitates the use of large retention tank and sedimentation tanks to allow time for precipitation to occur. A separate filtration step is then required to remove the remaining particulate.
In treating iron-laden water, the catalytic properties of the form of granular activated carbon perform quite differently from standard activated carbon. The catalytic properties greatly accelerates the reaction time of iron to an insoluble form. By oxidizing iron from a soluble to less soluble state, catalytic carbon serves to simplify the removal.
The resultant increase in reaction rate that occurs by using catalytic carbon allows smaller pieces of equipment to be used. As with all oxidation techniques, oxygen is required ~ but a simple eductor or air injection pump is all that is required. As the reaction occurs, the precipitate is collected on the surface of the carbon, and a secondary filter is not required. Periodic backwashing is performed to remove this iron floc and return the carbon to a usable state.
Another benefit of the catalytic carbon is its proven performance in removing hydrogen sulfide (H2S) from water. Many iron-containing waters also contain H2S and same bed of catalytic carbon can be used to remove both.
Similarly, the unique reactive nature of the internal surface of activated carbon means that there is an inherent ability for the promotion of reactions between gases and liquids that would either proceed too slowly or generate uneconomic yields of final product. This is achieved without the need for the addition of a chemical reagent to the activated carbon and often true catalysis proceeds, without degradation of the surface or adsorbent.
2 - 1054 Tanks
2 - AQT-56 FT Timer Valve
2 - Bypass 1" pipe connection
Units are shipped preloaded with media