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Water is important to your body. Approximately 70% of your body is water; 85% of the gray matter of the brain is water. Water is important in equalizing the temperature throughout the body. Water serves as a lubricant for moving surfaces such as joints, the heart and intestines. Water dissolves or holds in suspension other materials in your protoplasm. The sense organs of equilibrium depend upon the presence of water. Sound is conducted through the inner ear. The transparency of the media of the eye to light is maintained by water. Water (cerebrospinal fluid) serves as a cushion for the brain and spinal cord. Water moistens the surface of the lungs for gas diffusion. Water is the medium for digestion, absorption, metabolism, secretion and excretion. (These processes can only take place in the presence of water.) Doctors recommend drinking 8 glasses of water daily for good health. Chemicals and other impurities in our drinking water can attack and damage our vital organs. With all these important functions of water in your body… Doesn't it make good sense to put only high quality conditioned water into your body? The Benefits of Chlorine: Chlorine kills bacteria, fungus, algae and mold in municipal water delivery systems. Chlorine kills and inhibits algae and bacteria growth in swimming pools. It is most commonly known as bleach. Chlorine makes your drinking water appear to be pure and refreshing. The Disadvantages of Chlorine: It does not remove harmful metal contaminates present today in most water systems. Chlorinated water affects the taste of everything it's mixed with. Examples: Coffee, Tea, Juices, Soups & all concentrated or powdered food products. But worst of all… There is overwhelming evidence that prolonged and continued ingestion of chlorine and harmful metals (such as lead) causes serious health problems and increases the risks of cancer. Why You Shouldn't Drink Chlorinated Water Chlorine added to water acts as a disinfectant to kill disease-causing microorganisms that can infect humans. Fifteen years ago it was discovered that chlorine reacts with naturally occurring organic material and synthetic organics to produce by-products called trihalomethanes (THM's). The THM's have been found to be highly mutagenic and carcinogenic (cancercausing). The National Cancer Institute recently published a study showing that trace amounts of THM's increase our risk for bladder cancer which inflicts over 40,000 people a year. They found that long-term exposure, 40 to 60 years, to chlorinated drinking water could increase your risk for bladder cancer by 40 to 80 percent. This is pretty serious considering that according to the EPA about 75% of the U.S. population drinks chlorinated water. How Can the Problems be Solved? By Point of Entry and Use Filtration. This type of filter lets the chlorine stay in the delivery system to do the good for which it is intended. The chlorine is removed immediately on demand at the time of point of entry or use. Harmful metals and other contaminates can also be removed at the same time, if the filter is designed to do so. We recommend THREE GRADES of water for our homes. 1) Utility Grade for outside use, lawns, fighting fires, etc. 2) Conditioned Grade for washing clothes, dishes, cars, showers, etc. 3) Food Grade for cooking and drinking. If your water has over 2 grains of hardness, you need conditioned water. Each year we waste $1.8 billion on cleaning supplies, $2.7 billion on plumbing damages, $1 billion replacing washables and linens and $800 million on fuel bills because of hard water. With conditioned water you can save up to 80% on laundry soap and clothes stay brighter, fluffy and last longer. Reduce the need for expensive hair conditioners, conditioned water leaves no soap curd that results in dry, flaky scalp. Hard water impurities and soap scum will clog the pores of your skin. Your skin will become dry, flaky, itchy, wrinkled and begin to show premature age. Conditioned water will help unclog your pores and aid in keeping your skin healthy. Conditioned water is a natural moisturizer, it leaves skin soft and healthy without the aid of expensive creams and lotions. Conditioned water will also give you a clean, smooth shave and your razor blades will last longer. Save time; an Ohio State university Study showed that conditioned water will save 10 eight-hour days of housework per year. Hard water creates build up in plumbing that requires 22% more electricity to heat water and eventually requires replacement. |
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What Carbon Can Reduce or Remove
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| Diethyl phthalate | Alpha Naphthol | |
| 4-Dimethylaminoazobenzene | beta-Naphthol | |
| N-Dimethylaminoazobenzene | Alpha-Naphthylamine | |
| 2, 4-Dimethylphenol | Beta-Naphthylamine | |
| Dimethyl (phenethyl) carbinol | P-Nitroaniline | |
| Dimethyl phthalate | Nitrobenzene | |
| 4.6 Dinitro-o-cresol | 4-Nitrobiphenyl | |
| 2.4 Dinitrotoluene | 2-Nitrohenol | |
| 2.6 Dinitrotoluene | 4-Nitrophenol | |
| Diphenylamine | N-Nitrosodiphenylamine | |
| 1.1 Diphenylhydrazine | N-Nitrosodi-n-propylamine | |
| 1.2 Diphenylhydrazine | p-Nonylphenol | |
| Endrin | PCB 1221 | |
| Ethylbenzene | PCB 1232 | |
| Ethylenediaminetetraacetic acid (EDTA) | Pentachlorophenol | |
| Bis (2-ethylhexyl) phthalate | Phenanthrene | |
| Fluoranthene | Phenol | |
| Fluorene | Phenylmercuric acetate | |
| 5-Fluorouracil | Styrene | |
| Guanine | 1,1,2,2-Tetrachloroethane | |
| Heptachlor | Tetrachloroethane (tetrachloroethylene) | |
| Heptachlor epoxide | 1,2,3,4-Tetrahydronaphthalene | |
| Hexachlorobenzene | Thymine | |
| Hexachloro-1, 3-butadiene | Toluene | |
| Hexachlorcyclopentadiene | 1,2,4-Trichlorobenzene | |
| Hexachloroethane | 1,1,1-Trichloroethane | |
| Hydroquinone | 1,1,2-Trichloroethane | |
| o-Inisdine | Trichloroethane (trichloroethylene) | |
| Isooophorone | Trichiorofluormethane | |
| Methylene chloride | 2,4,6-Trichlorophenol | |
| 4.4 Methylenebis (2-Chloroaniline) | Uracil | |
| Naphthalene | p-Xylene | |
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What Contaminants Do Activated Carbon Filters Remove From Water? |
Activated carbon (AC)
filtration is most effective in removing organic contaminants from water.
Organic substances are composed of two basic elements, carbon and hydrogen.
Because organic chemicals are often responsible for taste, odor, and color
problems, AC filtration can generally be used to improve aesthetically
objectional water. AC filtration will also remove chlorine. AC filtration is
recognized by the Water Quality Association as an acceptable method to maintain
certain drinking water contaminants within the limits of the EPA National
Drinking Water Standards (Table 1).Table 1. Water contaminants that can be reduced to acceptable
standards by activated carbon filtration.
(Water Quality Association, 1989)
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Primary Drinking Water Standards Contaminant *MCL, mg/L Inorganic Contaminants Organic Arsenic Complexes 0.050 Organic Chromium Complexes 0.050 Mercury (Hg+2) Inorganic 0.05 0.050 Organic Mercury Complexes 0.002 Organic Contaminants Benzene 0.005 Endrin 0.002 Lindane 0.004 Methoxychlor 0.100 1,2-dichloroethane 0.005 1,1-dichloroethylene 0.007 1,1,1-trichloroethane 0.200 Total Trihalomethanes (TTHMs) 0.100 Toxaphene 0.005 Trichloroethylene 0.005 2,4-D 0.100 2,4,5-TP (Silvex) 0.100 Para-dichlorobenzene 0.075
Secondary Drinking Water Standards
Contaminant **SMCL Color 15 color units Foaming Agents (MBAS) 0.5 mg/l Odor 3 threshold odor number
---------------------------------------*Maximum Contaminant Level**Secondary Maximum Contaminant LevelAC filtration does remove some organic chemicals that can be harmful if present in quantities above the EPA Health Advisory Level (HAL). Included in this category are trihalomethanes (THM), pesticides, industrial solvents (halogenated hydrocarbons), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs).
THMs are a byproduct of the chlorination process that most public drinking water systems use for disinfection. Chloroform is the primary THM of concern. EPA does not allow public systems to have more than 100 parts per billion (ppb) of THMs in their treated water. Some municipal systems have had difficulty in meeting this standard.
The Safe Drinking Water Act mandates EPA to strictly regulate contaminants in community drinking water systems. As a result, organic chemical contamination of municipal drinking water is not likely to be a health problem. Contamination is more likely to go undetected and untreated in unregulated private water systems. AC filtration is a viable alternative to protect private drinking water systems from organic chemical contamination.
Radon gas can also be removed from water by AC filtration, but actual removal rates of radon for different types of AC filtration equipment have not been established.
Water Contaminants Not Removed by AC Filtration
Similar to other types of water treatment, AC filtration is effective for some contaminants and not effective for others. AC filtration does not remove microbes, sodium, nitrates, fluoride, and hardness. Lead and other heavy metals are removed only by a very specific type of AC filter. Unless the manufacturer states that its product will remove heavy metals, the consumer should assume that the AC filter is not effective in removing them. Refer to the other circulars in the Treatment Systems for Household Water Supplies series for information on systems that do remove the contaminants listed above.
Water Testing
Regular water testing is recommended to reduce the risk of consuming contaminated water. Many contaminants are not detected by the senses. Even if contamination can be detected by color, smell, or taste, only a laboratory test can tell you the quantity of contaminant actually present. Testing should always be done by a reputable or certified laboratory. Prior to sending in your water sample, determine what you want your water tested for. Contact the laboratory to find out how to take a proper water sample. Remember, there are thousands of substances that can contaminate your water, and they all have slightly different chemical behavior. Proper sampling and handling for one type of contaminant may cause erroneous results for other types of contaminants.
Once you have the laboratory results in hand, make sure you understand the numbers. If you don't fully understand the results, don't assume anything. The testing laboratory will be able to answer any questions you may have regarding your test results. Understanding the laboratory results will help you select the best and most economical water treatment system. Sometimes just a single piece of equipment, such as an AC filter, is all that is necessary to treat the problem. Other times you may need completely different equipment or possibly a combination of equipment. It all depends on the type and amount of contaminants present in your water.
The Activated Carbon Filtration Process
AC works by attracting and holding certain chemicals as water passes through it. AC is a highly porous material; therefore, it has an extremely high surface area for contaminant adsorption. The equivalent surface area of 1 pound of AC ranges from 60 to 150 acres.
AC is made of tiny clusters of carbon atoms stacked upon one another. The carbon source is a variety of materials, such as peanut shells or coal. The raw carbon source is slowly heated in the absence of air to produce a high carbon material. The carbon is activated by passing oxidizing gases through the material at extremely high temperatures. The activation process produces the pores that result in such high adsorptive properties.
The adsorption process depends on the following factors: 1) physical properties of the AC, such as pore size distribution and surface area; 2) the chemical nature of the carbon source, or the amount of oxygen and hydrogen associated with it; 3) chemical composition and concentration of the contaminant; 4) the temperature and pH of the water; and 5) the flow rate or time exposure of water to AC.
Physical Properties
Forces of physical attraction or adsorption of contaminants to the pore walls is the most important AC filtration process. The amount and distribution of pores play key roles in determining how well contaminants are filtered. The best filtration occurs when pores are barely large enough to admit the contaminant molecule (Figure 1). Because contaminants come in all different sizes, they are attracted differently depending on pore size of the filter. In general AC filters are most effective in removing contaminants that have relatively large molecules (most organic chemicals). Type of raw carbon material and its method of activation will affect types of contaminants that are adsorbed. This is largely due to the influence that raw material and activation have on pore size and distribution.
Figure 1. Molecular screening in the micropores of an activated carbon filter. (after G. L. Culp and R. L. Culp)
Chemical Properties
Processes other than physical attraction also affect AC filtration. The filter surface may actually interact chemically with organic molecules. Also electrical forces between the AC surface and some contaminants may result in adsorption or ion exchange. Adsorption, then, is also affected by the chemical nature of the adsorbing surface. The chemical properties of the adsorbing surface are determined to a large extent by the activation process. AC materials formed from different activation processes will have chemical properties that make them more or less attractive to various contaminants. For example chloroform is adsorbed best by AC that has the least amount of oxygen associated with the pore surfaces. The consumer can't possibly determine the chemical nature of an AC filter. However, this does point out the fact that different types of AC filters will have varying levels of effectiveness in treating different chemicals. The manufacturer should be consulted to determine if their filter will adequately treat the consumer's specific water problem.
Contaminant Properties
Large organic molecules are most effectively adsorbed by AC. A general rule of thumb is that similar materials tend to associate. Organic molecules and activated carbon are similar materials; therefore there is a stronger tendency for most organic chemicals to associate with the activated carbon in the filter rather than staying dissolved in a dissimilar material like water. Generally, the least soluble organic molecules are most strongly adsorbed. Often the smaller organic molecules are held the tightest, because they fit into the smaller pores.
Concentration of organic contaminants can affect the adsorption process. A given AC filter may be more effective than another type of AC filter at low contaminant concentrations, but may be less effective than the other filter at high concentrations. This type of behavior has been observed with chloroform removal. The filter manufacturer should be consulted to determine how the filter will perform for specific chemicals at different levels of contamination.
Water Temperature and pH
Adsorption usually increases as pH and temperature decrease. Chemical reactions and forms of chemicals are closely related to pH and temperature. When pH and temperature are lowered many organic chemicals are in a more adsorbable form.
Exposure Time
The process of adsorption is also influenced by the length of time that the AC is in contact with the contaminant in the water. Increasing contact time allows greater amounts of contaminant to be removed from the water. Contact is improved by increasing the amount of AC in the filter and reducing the flow rate of water through the filter.
Activated Carbon Filtration Equipment
AC filters can be placed in the three following categories: 1) pour-through; 2) faucet-mounted; and 3) high-volume (Figure 2).
Figure 2. The three types of activated carbon filtration units are: A) pour-through; B) faucet-mounted; and C) high-volume.
Pour-through AC filters are the simplest. They work like a drip coffee maker. Water is poured in the top and filters by gravity through the filter to the bottom. They are quite slow and handle only small volumes of water.
Faucet-mounted AC filters are small units attached on the end of a standard kitchen faucet. They are convenient to use, but because of their size require frequent change. Some units have bypass valves, so that just water for cooking and drinking is filtered.
High-volume AC filters contain much more AC than either the pour-through or faucet-mounted models. High-volume units are designed to be installed in-line, generally under the sink. They are installed on the cold water line, and some units are installed with a bypass to separate cooking and drinking water from other uses. Under exceptional circumstances all water may need to be treated by AC filtration. A high-volume unit may be installed at the point of entry to the house if all water needs to be treated.
Results of Activated Carbon Filter Testing
In recent years several independent laboratories have tested AC filtration equipment for effectiveness in contaminant removal. Organizations involved in AC testing are the Gulf South Research Institute, National Sanitation Foundation, Canadian Bureau of Health, Consumer Reports and Rodale Press Product Testing Department.
Based on the testing results of these organizations, general recommendations can be made regarding AC filtration. High-volume AC units should be used if removal of health threatening contaminants is your concern. Pour-through and faucet-mounted units do not provide the contact time for significant removal of contaminants. If you are only concerned with taste, odor, or color, pour-through and faucet-mounted units will probably do the job. However, they will still require changing much more often than high-volume AC filters.
Efficiency of contaminant removal and equipment operation vary even among the high volume AC units (Table 2). The most efficient unit is not always the most expensive one.
Table 2. A comparison of activated carbon filtrationunits. (Consumer Reports, 1990)-----------------------------------------------------
Cartridge ChloroformBrand and Model Price $ Cost $ Removal % High-Volume Filters Ametek CCF-201 158 20(2) 100 Ecowater Water Master 250 33(2) 100 Amway E-9230 276 69 90 Hurley II 375 - 100 Filtrate CF 10 85 8 90 Cuno AquaPure AP-CRF 155 15 90 Kinetico MAC 275 32 90 Culligan SuperGard THM 349 37 90 Teledyne Instapure IF-10 50 12 80 Omni UC-2 99 20(2) 80 NSA Bacteriostatic 158 158 158 (The following two models were downrated becausethey clogged after filtering only 300 gallons.)Bionaire H20 BT850 199 100 100 Everpure H200 298 90 100 Faucet-Mount Filters Cuno Purity PPO1105 30 6 60 Teledyne Instapure F-2C 24 5 54 Pollenex WP90K 22 5 30 Pour-Through Filters Brita 30 8 50 Innova 7 5 45 Glacier Pure 13 5 40 Eventually the AC filter loses its ability to remove contaminants, because it becomes clogged with material. In the case of taste and odor, the time to change the filter is easy to detect. However, in the case of other contaminants, it is more difficult to determine when the filter is no longer performing at an adequate level. Most manufacturers recommend a filter change after a certain volume of water has passed through the filter. Some AC units actually meter the water and automatically shut down after a specific quantity of water has passed through the filter. General recommendations are somewhat useful quidelines, but there is no guarantee that they apply to any specific situation. Remember, the only certain way of knowing whether contaminant levels are acceptable or not is by having your water tested.
A sediment filter installed ahead of any AC filter will prolong the life of the AC unit. Sediment can easily clog the pores of an AC filter within a short period of time. A good sediment filter can be purchased for only a fraction of the price of most high volume AC filters.
The Bacteria Issue
AC filters can be a breeding ground for microorganisms. The organic chemicals that are adsorbed to the AC are a source of food for various types of bacteria. Pathogenic bacteria are those that cause human diseases such as typhoid, cholera, and dysentery. Public water systems must treat for disease causing bacteria; therefore, the likelihood of disease causing bacteria being introduced to an AC filter from public drinking water is remote. AC filtration should only be used on water that has been tested and found to be bacteria free or effectively treated for pathogenic bacteria.
Other types of non-pathogenic bacteria that do not cause diseases have been regularly found in AC filters. There are times when high amounts of bacteria (non-pathogenic) are found in water filtered through an AC unit. Research by R. L. Caldron and E. W. Mood (1987) shows little risk to healthy people that consume high amounts of non-pathogenic bacteria. We regularly take in millions of bacteria every day from other sources. However, there is some concern for certain segments of the population, such as the very young or old and people weakened by illness. Some types of non-pathogenic bacteria can cause illness in those whose natural defenses are weak. Flushing out bacteria that have built up in the filter can be accomplished by running water through an AC filter for about 30 seconds prior to use. Water filtered after the initial flushing will have much lower levels of bacteria and ingestion of a high concentration of bacteria will have been avoided. The flushing procedure is most important in the morning or any other time of the day when the filter has not been used for several hours.
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© 2000 LaPure Water, Inc.
Last Modified 02/18/2006 |