- Activated carbon filters for water how do they work?
- What is activated charcoal?
- How does activated carbon work in water filters?
- Types of activated carbon filters
The use of the activated carbon filter is the most suitable for drinking safe water. When the water passes from the filter, it attracts all the impurities and filters them out. The only downside of this filter is its price. Usually, the cost of two activated carbon filters is $20. But you can enhance the lifespan of the filter with its cleaning. The cleaning makes the filter more effective for the removal of contaminants. This article will show you how to clean an activated carbon water filter.
The cleaning of a carbon filter is similar to cleaning of RO filters. But it needs more attention with full care. In the cleaning of activated carbon filters, we use different chemicals. Therefore, it requires a well-ventilated place.
Steps to clean wet activated carbon water filter
These steps help you in the cleaning of the wet activated carbon filter. With the following steps, you will quickly clean the carbon water filter.
Step 1: Use Caution
Safety precautions should be your priority. No matter what kind of acid use with water, always adopt the safety measures. Always choose a well-ventilated area or go outside. The breathing in of any chemical will lead to burning of the nasal cavity or cause vomiting.
The protection of yourself from harmful chemicals is essential. It is good to wear rubber gloves that protect your hands. Also, wear a facemask with safety goggles for the protection of the face. Further, it is also a great idea to wear old clothes. The cleaning of the activated carbon filter is a little tricky. So, always follow the preventive measures for safe cleaning.
Step 2: Mix the Chemicals
For the cleaning, you will need two buckets. Take all the materials with buckets outside the house. Now, fill one bucket with clear tap water. Fill the bucket with half-gallon water. Now leave the water for a short time to match with the outside temperature. Furthermore, you will need a glass measuring cup for the measuring of chemicals.
We used muriatic acid for the cleaning process. So, we recommend you to use this acid because it is very efficient in its working. You have to use a plastic stirrer for the stirring of acid in the water. So, keep the plastic stirrer aside before start to make a chemical solution. After that, add the muriatic acid gradually to the bucket of water.
Continuously stir the acid in the water with the help of the plastic stirrer. It is critical to know that never add more water when you add acid in the water’s bucket. Otherwise, it causes dangerous fumes and also may cause an explosion. Thereby, mix the chemical in water carefully.
Step 3: Remove Debris
Over time, the activated carbon filter becomes too dirty. The dirty filter will not able to produce filtered water very well. For the washing of the carbon filter, you will require a hose with high-pressure. The high-pressure of water enables to wash the filter accurately. You have to spend extra time in those areas where there is severe build-up of calcium.
Also, give attention to rusting part of the filter. The tap water removes all the debris & particles from the filter. The removal of debris from the activated carbon filter makes the filter more efficient. Wash all sides of the filter to get the maximum effect of the cleaning of the filter. The carbon filter becomes highly efficient with the removal of dust and debris.
Step 4: Using the Acid
With a hose, you can only remove calcium and debris from the carbon filter. After the removal of debris, now it’s time to use acid for the cleaning. The use of muriatic acid is the final step for the cleaning of the filter. After this step, the filter is almost ready to use.
Place the carbon filter in the bucket of a chemical solution (acid & water). The filter should sink in the bucket’s bottom. This bucket should present in a good ventilation area. Leave the filter in this bucket for 1-week. With time, the filter becomes cleaner in the chemical solution. Never allow children to go near this bucket.
Step 5: Final Cleanse
After some days, the acid shows you its high-quality performance. This acid will remove calcium and other materials from the filter. Besides, the acid will refresh the inside of the carbon filter. At that point, take a second bucket fill it with half gallon water. The water should clean. Take out the carbon filter from the bucket of acidic solution with the help of tongs.
Then, place the filter in the bucket of clean water. After that, leave the filter in the clean water for 5-minutes. The purpose of leaving the filter in clean water is to remove acid from the filter. At last, rinse the activated carbon filter with the hose. The carbon filter becomes clean. And it becomes more enabling to make filtered water.
Steps to Clean, dry activated carbon filter:
The cleaning of a dry activated carbon filter is different from a wet filter. These steps show you how to clean a dry carbon filter.
First of all, take the carbon filter from the filter system’s housing.
The second step involves the attaching of the crevice tool to the vacuum’s hose. After that, vacuum carbon filter’s one side in the horizontal motion. In this way, it will remove all dust & dirt from the carbon filter. You can easily vacuum an activated carbon filter from its top side towards the bottom. Then, repeat this process on another side of the filter.
The third step involves the vacuuming of the housing of the filter. The air grate of the filter housing should clean from any damp cloth. Then, wipe the housing with a different cloth.
Lastly, put the activated carbon filter again in its housing.
The rinsing of the activated carbon filter is also acceptable. But remember one thing that the cleaning of the filter will never eliminate toxins or other build-ups. However, cleaning is necessary for the maintenance of the activated carbon filter.
Activated carbon filters for water how do they work?
First, we would like to explain what activated carbon is to later explain how it works in home and industrial water filters.
What is activated charcoal?
Activated charcoal is made from carbon-rich organic materials that burn at high temperatures. These carbon-rich materials go through a high-temperature carbonization process (between 600 and 900 degrees Celsius or 1110 and 1650 degrees Fahrenheit).
The result of this carbonization is activation , it gives a more porous charcoal than the normal charcoal that we know for grilling food. So the term “activated carbon” could also be called “ porous carbon ”.
Any carbon in nature has the ability to adsorb organic compounds on its surface, but by activating it or creating more pores in it, that surface area is increased to trap these substances. That is why it is a good purifier for organic pollutants .
Raw materials with which activated carbon is produced.
The choice of materials to make activated carbon is due to its abundance in the world, there are practically three abundant and carbon-rich natural elements with which activated carbon is manufactured:
1 Wood : it is the softest material of the three, so it makes larger pores and retains large organic compounds (color, proteins …) Used to discolor liquids and oils. This charcoal is typically applied in powder form.
2 The coconut shell or other hard shells , is the hardest material with which activated carbon is produced, so the activation generates micro pores, and makes it more suitable for water purification, since it retains smaller organic compounds. Also applications for air and gas treatment.
3 Coals of mineral origin . These are created by nature over hundreds of years, so they have softer sections than others, and generate a range of pores from micro to macro pores. which makes this coal very versatile from water purification to tertiary wastewater treatment.
One way to measure the degree of activation of carbon is to measure its surface area . The approved laboratory test is the iodine number test . Iodine is an element that carbon traps in a monolayer and the iodine solution that is adsorbed by carbon indicates the amount of surface area that it can have. The greater the amount of iodine adsorbed, the greater the active surface area that a carbon has.
Typical granulometries used in activated carbon and how it affects its size.
In general, activated carbon works better the smaller the carbon particle . This means that a powdered activated activated carbon will work faster and more efficiently than a larger grain, due to kinetics , a small variation in the size of the carbon particles can have a significant impact on the water flow and on the performance for the trap pollutants.
For home water filters, 20 x 50 mesh (0.84 to 0.29 millimeters) granular activated carbon is used. Being a small cartridge where the contact time is relatively short, a small grain is used, with it we ensure that the chlorine is removed correctly and the contaminants, maintaining an acceptable pressure drop.
The industrial systems use a mesh size range 12 x 40 (1.68 to 0.42 mm) or 8 x 30 (2.38 to 0.59 mm). This larger particle size still allows fast kinetics and acceptable pressure drop, smaller carbon particles are not used due to pressure drop and material can escape from manifolds or nozzles. In addition, these coals once depleted can be thermally reactivated later, with cost savings and also environmental benefits from waste.
This could mean that a powdered activated carbon with a low iodine number may outperform a granular activated carbon with a higher iodine number.
How does activated carbon work in water filters?
The most widely used purification application of activated carbon is in water treatment, commonly after disinfection during which chemical reactions can occur. In addition, the water is usually disinfected before it passes through the activated carbon adsorbents to prevent bacterial growth. Activated carbon works as a granular filter medium to remove organic compounds that are considered undesirable in drinking water.
What does activated carbon remove from water?
Eliminate organic pollutants in the water.
Organic contaminants in water can give the taste and smell to water , such as detergents, pesticides, some fats and oils, toxins, organic chemicals, compounds caused by the decomposition of vegetables and plants, or by animal waste.
Remove chlorine from the water.
This is the easiest application for activated charcoal in water. The destruction of chlorine is by a reduction process, because activated carbon is a reducer of any oxidant (chlorine, ozone, hydrogen peroxide …) Except chlorine dioxide.
Where the chlorine when making contact with the coal this generates a reduction reaction and converts the chlorine into hydrochloric acid at very low concentrations (not harmful to humans).
What does activated charcoal NOT remove from water?
It does not eliminate inorganic compounds such as: arsenic, student, calcium, iron, fluorine, lead, mercury, phosphates, sodium … Some also called heavy metals.
It also does not eliminate microorganisms such as viruses and bacteria . So it is necessary to use another type of treatment to eliminate them. What can happen is that when an activated carbon retains organic matter, it could have some bacterial contamination, which would become a fertile bed for the proliferation of bacteria. In those cases where it is necessary to change cartridges with certain frequency or in industrial applications a programmed sanitization protocol is necessary .
Activated carbon impregnated with silver to prevent the growth of bacteria
There is a process in the manufacture of activated carbon in which silver can be impregnated with a chemical method. Silver is a bacteriostatic agent , that is, it prevents bacteria from developing in the place where there is silver , but not to be confused with a bactericidal agent, since it does not kill the bacteria, it only prevents them from remaining and developing in the place.
As we saw the coal bed sooner or later, it can become contaminated with bacteria that come from an un-disinfected point. Bacteria reproduce, turning the coal bed into a source of contamination.
In order to inhibit bacterial growth, the surface of the carbon is impregnated with metallic silver.
This method can make activated carbon more expensive, since silver has a high market value, activated carbon is normally impregnated with silver for domestic or low-volume carbon applications, for example in cartridges. For industrial use it is not common.
Types of activated carbon filters
• Cartridge filters
The Activated Carbon Cartridge is made for home, restaurant, or low flow industry applications. It is a closed cartridge that can contain from 300 grams to 4 kg of activated carbon, depending on the size.
The cartridges are used for water purification, which is why they normally use coconut shell charcoal as raw material.
There are two main types : the granular activated carbon (GAC) cartridge and the extruded or block activated carbon cartridge “Carboblock”.
1 Granular Activated Carbon Cartridge Filter
This is filled in an empty cartridge with activated carbon grains , and sealed at both ends of the casing, the two ends of the cartridge are respectively placed in a filter mesh or cloth, to prevent the carbon grains from leaving the cartridge. Depending on the customer’s needs, the cartridge end caps can be made on different types of connectors, the most typical being flat connections for standard cartridges, but there are lance or double gasket terminations for industrial or laboratory applications.
The granulometry used in the granular cartridges is 20 × 50 US sieve mesh.
2 “Carboblock” extruded or block activated carbon cartridge
The block or extruded activated carbon filter cartridge uses powdered carbon and this is formed into a block with the help of a food grade binder. This compacted carbon block is covered with a layer of filter cloth, to prevent the carbon core from shedding dust or warping. The carbon cartridge has a nitrile rubber cap at its ends so that it is well sealed.
The filter mesh that covers this cartridge can act as a sediment filter, normally it filters at 5 or 10 microns.. So it can be considered that it performs two functions in a single step. We always recommend placing a cartridge to retain additional sediment, before the bulk cartridge, because its filtration area is very small and could be plugged prematurely before the activated carbon has to be changed.
Applications for Cartridge Activated Carbon Filters
In addition to being used in our home water purifiers, activated carbon cartridge filters are suitable for process water purification and solutions in the semiconductor industry, electronic devices, ink printing machines, the electroplating industry. and the food and beverage industry. It is applicable to the following industries:
1. Chemical and petrochemical industry: solvents, paint, detergents and liquid wax, etc.
2. Pharmaceutical and pharmaceutical industry: hospital water, pharmaceutical injections, medium liquids, etc.
3. Electronic industry: electric liquid, printing line, etc.
4. Food industry: food, beverages, drinking water, alcohol, etc.
Activated carbon fish tank filters, this cartridge uses a larger special type of carbon pelletized to 3 or 4 millimeters.
These cartridges go inside a cartridge holder or filter holder that channel the flow so that the water passes through the cartridge, made of polyethylene that meets NSF standards. With 1/4 ″, 1/2 ″ 3/4 ″, 1 ″ and 1.5 ″ inlets.
• Activated carbon bed filters (and industrial and municipal applications)
Industrial activated carbon filters, as we have already seen, have the same purpose, to eliminate chlorine, taste, odor and color, either with activated carbons of bituminous mineral origin or coconut shell carbon.
We also saw in the section on granulometry that for this application we are going to use sizes (mesh), 12 x 40 or 8 x 30.
When we decide that an industrial activated carbon water system is necessary, it is essential to know the characteristics of the water . In the case of municipal or well water from a reliable source, we can expect that there will be a minimal amount of contaminants and we can use a coconut shell activated carbon . In the event that the water source has a high turbidity, more amount of total organic compounds (TOC), which are found in surface water of a river or lake, in these cases we see that the use of activated carbon of bituminous mineral origin.
Components of industrial activated carbon water filters.
1. Control valves: (mounted on the top or side) their function is to channel the flow of water through the activated carbon bed to treat it and deliver the already purified product, but a primary function is the cleaning of the granular medium (in this case coal). What the valve does to clean excess sediment and impurities is to change the direction of the water flow to expand the carbon bed and expel the retained sediment. Some valves are manual and others are automatic , so in the latter this self-cleaning or backwashing will be done automatically with prior programming.
The valve can be configured to operate as a single stand-alone unit or as multiple filters operating in parallel or in sequence, depending on the application.
Smaller filters can have valves while there are larger filters that cannot carry a poppet valve, and can be configured with air-actuated or electric (Aquamatic) diaphragm valves that carry a controller. digital.
2. Filter media: Gravel and activated carbon). ACFs are available in different media volume and flow capacities. We must ensure that the minimum backwash flow is (10-12 GPM / ft2) to ensure that it is operating in optimal conditions and to prolong the life of the charcoal.
The activated carbon in the tank should have a maximum of 50% of the total volume, to allow the activated carbon bed to expand (30% – 40%) during the backwash. The activated carbon bed should be replaced when the effectiveness to remove the contaminants is exhausted or every 2 years at most.
3. Pressure tank: The cylindrical element that will contain the activated carbon, is typically made of polypropylene, covered with fiberglass. There are industry applications that require carbon steel or stainless steel tanks.
4. Nozzles or distributors and central tube: The nozzles are an essential element in the system, it is a slotted element that prevents the granular medium from leaving the filter with the flow of water. Made of PVC or stainless steel with aperture measurement slots between 0.18 to 0.20 millimeters, with which we prevent the smallest carbon 12 × 40 mesh (1.68 to 0.42 mm) from escaping from the filter.
The central tube collects the treated water and carries it to the outlet of the system.
Industrial activated carbon water filter systems are used as a pretreatment for reverse osmosis systems, as reverse osmosis membranes cannot have chlorine in the feed water. Chlorine chemically attacks membranes, degrading and damaging their composition.
Applications for activated carbon bed filters.
1. Drinking water for industrial use or production lines.
2. Purification of water for human use in sanitary services.
3. Treatment of water for the food industry and bottled beverages.
4. Pretreatment for reverse osmosis systems.
5. Tertiary treatment of industrial and sanitary wastewater.
Water is one of the most valuable resources in the world. As the world’s population grows, efficient water treatment will continue to grow as well. Activated carbon offers an effective solution in many water treatment applications, whether it is to ensure that drinking water is safe for human consumption, to protect river bodies from potentially contaminated effluent discharge , or to help manufacture premium products. quality.