EL USO DEL CARBON ACTIVO EN FILTRACION DE AGUA (EN INGLES)

Activated Carbon in Water Filtration

Among other applications, activated carbon is often used to filter contaminants out of drinking water. After water testing, filtration can be manipulated to remove specific contaminants so the water can meet EPA National Drinking Water Standards. Specifically, activated carbon filters are useful for removing organic compounds, which are often the cause of changes in the taste, smell, and appearance of water. Because organic compounds are comprised of hydrogen and carbon, carbon filters work well with these types of contaminants. Filtration can remove harmful chemicals, such as trihalomethanes (THMs), pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). If these chemicals are present in quantities above EPA standards, the water is potentially dangerous to drink.

 

Despite active carbon filtration’s ability to remove several types of harmful chemicals, it is not effective in the removal of all contaminants. Heavy metals, such as lead, can be removed using active carbon filtration, but require a special kind of filter. Microbes, nitrates, and fluoride are examples of contaminants that cannot be filtered effectively using active carbon.

 

The Filtration Process

 

In order to efficiently remove contaminants, active carbon filtration depends on active carbon’s highly porous properties. The contaminants are adsorbed by the high-surface area carbon, which consists of multiple carbon atoms clumped together. The adsorption of contaminants is contingent on several other properties, such as the size of carbon pores, and the amount of hydrogen and carbon the carbon sample contains. Contaminant adsorption largely depends on the carbon’s pore size, as well as the size of the contaminant itself. Generally speaking, contaminants with larger pores are easier to filter out, but other factors, such as water pH, temperature, overall concentration of the contaminant, and nature of the carbon certainly come into play. (See page here).

 

Types of Filtration Systems

 

 Not all types of filtration systems work the same way. Some systems are easily incorporated into the home, whereas others are reserved for on-site water treatment at a plant. For do-it-yourself filtration, there are three common models of carbon activated filters.

 

Pour-Through Filters

Pour through activated carbon filters are common and simple in design. In a process somewhat akin to that of a drip coffee maker, water is poured in through the top of the filter, and drains out using gravity as the driving force. Because these filters are relatively slow, they are not recommended for use with high volumes of water. Instead, they are commonly used inside water-pitchers and included in at-home water filtration systems.

 

Faucet-Mounted Filters

Faucet-mounted filters are attached to the end of the faucet-head and filter the water as it flows through. Their small size and overall easy use makes them popular, but they need to be changed relatively frequently to ensure efficiency.

High-Volume Filters

High-volume filters make sense for treating large volumes of water. They contain a significantly high amount of activated carbon and are installed under the sink so as to filter the water before it even emerges from the faucet. If all water for the entire household needs to be filtered a carbon activated filtration unit can be installed at the water pipe where it enters the household. Generally, the systems are installed under sinks to provide filtered water solely for cooking and drinking.

 

Considerations

 

Many of the organic compounds which active carbon filtration removes encourage the presence of bacteria. Harmful disease-causing bacteria, such as cholera and typhoid, feed off bacteria a filter removes. In public water systems, the water is pre-treated for disease-causing bacteria, so water that enters the home or is used as public drinking water is unlikely to contain such bacteria.

 

It is common, however, for a fair amount of non-pathogenic bacteria to build up inside the active carbon filter. Although these types of bacteria don’t cause disease outright, it’s a good idea to change the filter or clean it on a regular basis. Common exposure to bacteria means that the human immune system is well-equipped to protect against basic bacteria, but those who have weaker immune systems are more susceptible—either way, regular cleaning of the filter is important in maintaining an effective active carbon system.