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• Source - Acidic waters usually come from acid mine waters, or acidic industrial wastes. Acid mine waters are frequently too low in pH to provide suitable drinking water even after neutralization.
• Solution - Acidic water can be corrected by injecting soda ash or caustic soda into the water supply to raise the pH. Applying these two chemicals slightly increases the alkalinity in direct proportion to the amount used. Acidic water can also be neutralized by running it through calcite or corosex. The calcite and the corosex both neutralize by dissolving. They add hardness to the water as the neutralization takes place and need to be replenished on a periodic basis. Back to Glossary

• Source - Aluminum is an abundant metal in the Earth's surface. The solubility in water is very low so it is seldom a concern in municipal or industrial water systems. The majority of natural water contains from 0.1 ppm to 9.0 ppm of aluminum. The primary source of aluminum in drinking water comes from the use of aluminum sulfate as a coagulant in water treatment plants. The total dietary exposure to aluminum salts averages around 20 mg/day. The US EPA's Secondary Drinking Water Standards list a suggested level of 0.05 -.20 mg/l for aluminum.
• Solution - Aluminum can be removed from water by a cation exchanger. However, hydrochloric acid or sulfuric acid must be used for regeneration to remove trapped aluminum from the resin. A cation exchanger is fine for industrial applications but not an ideal solution for domestic use.  Reverse Osmosis will reduce the aluminum content of drinking water by     98 + %. Distillation will reduce the aluminum content of water by 99 + %.                      Back to Glossary

• Source - Ammonia gas is normally expressed as nitrogen and very soluble in water. It occurs naturally as organic nitrogen compounds decay. Ammonia usually comes from runoff in agricultural areas where it is applied as fertilizer. It can also be found in underground aquifers from animal feed lots. Ammonia is oxidized to nitrate by bacterial action. A concentration of  0.1 to 1.0 ppm is typically found in most surface water supplies. Ammonia is not usually found in well water supplies because the bacteria in the soil converts it to nitrates. The concentration of ammonia is not restricted by drinking water standards at this time. Since ammonia is corrosive to copper alloys, it is a concern in cooling systems.
• Solution - Ammonia can be neutralized by chlorination. The initial reaction forms chloramine and must be completely broken down before there is chlorine residual. Chlorine will also destroy organic contaminants in a waste stream before reacting with ammonia. Cation exchange resin and degasification will also remove ammonia. Back to Glossary

• Source - Arsenic is not easily dissolved in water. If arsenic is found in a water supply, it has normally come from mining, metallurgical operations, or runoff from agricultural areas where materials containing arsenic were used. Arsenic and phosphate can be substituted for one another chemically, therefore commercial grade phosphate can have some arsenic in it. Arsenic is highly toxic and has been classified by the US EPA as a carcinogen. The current maximum contaminant level for arsenic is 0.01 mg/l.
• Solution - Arsenic can be reduced by conventional water treatment processes if it is still in an inorganic form. The ways to remove inorganic contaminants include; activated carbon, anion exchange, reverse osmosis, and distillation. Filtration through activated carbon will reduce the amount of arsenic in drinking water from 40 - 70%. Anion exchange will reduce it by 90 - 100%. Reverse Osmosis has a 90% removal rate and distillation will remove 98%. If the arsenic is present in organic form, it can be removed by oxidation of the organic material and subsequent coagulation. Back to Glossary

• Source - Bacterial contamination can result from a number of different sources.  Human and animal waste are the primary source for bacteria in water. These sources of bacterial contamination include runoff from feedlots, pastures, and other land areas where animal wastes are deposited.  Bacteria from these sources can enter wells that are either open at the land surface, or do not have water-tight casings or caps.  Insects, rodents, or animals entering the well are other sources of contamination.  Another way bacteria can enter a water supply is through infiltration by flood waters or surface runoff.  Flood waters commonly contain high levels of bacteria. Small depressions in the land filled with flood water provide a perfect breeding ground for bacteria.
• Solution - Bacteria can be treated by microfiltration, Ultra Violet Light, Reverse Osmosis, or chemical oxidation and disinfection.  The most common method of bacteria destruction is chemical oxidation and disinfection. Ozone injection into a water supply is one form of chemical oxidation and disinfection. A residual of 0.4 mg/l must be established and a retention time of four minutes is required. Chlorine injection is the most widely recognized method of chemical oxidation and disinfection. Chlorine must be fed at 3 to 5 ppm to treat bacteria and a residual of 0.4 ppm of free chlorine must be maintained for 30 minutes in order to meet US EPA standards. Reverse Osmosis will remove 99+ % of the bacteria in a drinking water system. If RO is used, it should be preceded by an Activated Carbon cartridge to remove chlorine which was used for disinfection. Back to Glossary

• Source - Barium can be the result of drilling wastes, discharge from metal refineries or erosion from natural deposits. It is highly toxic when its soluble salts are ingested. The current MCL for Barium is 2.0 mg/l.
• Solution - Water softeners are very effective at removing Barium. Reverse Osmosis is also effective in its removal. Back to Glossary

• Source - Benzene makes its way into water supplies from leaching of gas storage tanks, landfills, and discharge from factories. Benzene is a byproduct of petroleum refining and used in the production of synthesized plastics. It is also an additive in gasoline.  Benzene is classified as a volatile organic chemical (VOC) and is considered a carcinogen by the US EPA. The US EPA has set the MCL for Benzene at 0.005 mg/l.
• Solution - Benzene can be removed with Activated Carbon.  The activated carbon must be replaced when exhausted. Back to Glossary

• Source - Bicarbonate is the principal alkaline in almost all water supplies. Alkalinity in drinking water supplies seldom exceeds 300 mg/l. Alkalinity control is important in boiler feed water, cooling tower water, and the beverage industry. Bicarbonate alkalinity is introduced into the water by CO2 dissolving carbonate-containing minerals. Alkalinity neutralizes the acidity in fruit flavors. 
• Solution - The bicarbonate alkalinity can be reduced by removing the free CO2 through aeration.  A strong base Anion Exchanger will also remove alkalinity. Back to Glossary

• Source - Borate is a compound of Boron which is mostly found in sea water. Sodium borate is found in arid regions where inland seas once existed but have now evaporated. Boron will be found in fresh water supplies in these same areas in the form of non-ionized boric acid. The amount of boric acid is not currently limited by US EPA drinking water standards.
• Solution - Boron can be or adsorbed utilizing an Activated Carbon filter.                     Back to Glossary

• Source - Bromine is used in swimming pools and cooling towers for disinfection.  It should not be used as a disinfectant in drinking water. Bromine is extremely corrosive and will produce irritation and burning to exposed tissues. Bromide is extensively used in the pharmaceutical industry, and occurs normally in blood in the range of 1.5 to 50 mg/l.  Over 0.05 mg/l in fresh water may indicate the presence of industrial wastes,
• Solution - Reverse Osmosis will remove 93 -96 % of the bromide from drinking water. Bromine can also be removed with Activated Carbon.  Back to Glossary

• Source - Cadmium enters drinking water supplies as a result of corrosion of galvanized plumbing, erosion of natural deposits, discharge from metal refineries, and runoff from waste batteries. The US EPA Primary Drinking Water Standards lists Cadmium with a 0.005 mg/l MCL.
• Solution - Cadmium can be removed from drinking water with a water softener or through Reverse Osmosis. Back to Glossary

• Source - Calcium is the major component of hardness in water and is usually in the range of 5 - 500 mg/l.  It is derived from nearly all rock, but the greatest concentrations come from limestone and gypsum. Calcium ions are the principal cations in most natural waters. Complete removal is required in metal finishing, textile operations, and boiler feed applications.
• Solution - Calcium can be removed with a water softener. Reverse Osmosis will also remove 95 - 98 % of the calcium in the water. Back to Glossary

• Source - Carbon dioxide concentrations vary in most water supplies from almost zero to 50 parts per million. Surface waters generally contain larger amounts than wells or springs. Carbon dioxide combines with water to form carbonic acid which is a weak acid that accelerates corrosion. Excessive concentrations of carbon dioxide are generally indicated by low pH values.
• Solution - Carbon dioxide can be easily dissipated by aeration. It may also removed by raising the pH to 8.5 or above with a soda ash or caustic soda chemical feed system.     Back to Glossary

• Source - Carbon tetrachloride is a volatile organic chemical (VOC), and primarily used in the manufacture of chlorofluoromethane. It may enter water supplies through discharges from chemical plants or other industrial activities.  Many water supplies across the country have been found to contain measurable amounts of VOC's. The detection of VOC's in a water supply indicates that a pollution incident has occurred, because these chemicals are man-made. See Volatile Organic Chemicals for a listing of many VOC’s. The US EPA has listed carbon tetrachloride as a probable human carcinogen and set the the MCL at              0.005 mg/l.
• Solution - Reverse Osmosis will remove 70 to 80% of the VOC's in drinking water. Carbon tetrachloride as well as the other volatile organic chemicals (VOC's) can also be removed from drinking water with Activated Carbon filtration. The life of the carbon will vary with each type of VOC.  Back to Glossary

• Source- Chloride is a major anion found in water and is generally combined with calcium, magnesium, or sodium.  Chloride is responsible for the corrosion of piping because of the compounds formed with it. Corrosion rates increase as the sodium chloride content of the water is increased. The chloride ion is also instrumental in breaking down passivating films which protect ferrous metals and alloys from corrosion.  The suggested maximum contaminant level for chloride is 250 mg/l which is due to the salty taste produced in drinking water at that level..
• Solution - Reverse Osmosis will remove 90 - 95% of the chlorides. Electrodialysis and distillation are two more processes which can be used to reduce the chloride content of water. Back to Glossary

• Source- Chlorine is a commonly used agent for the disinfection of water supplies. During the chlorination process, the chlorine combines with natural organic matter to form compounds known as trihalomethanes.  These trihalomethanes include such carcinogens as chloroform, bromoform, carbon tetrachloride, bischloroethane and others. The amount of trihalomethanes in drinking water is regulated by the EPA. The current maximum allowed by law is 4 ppm.
• Solution - Chlorine can be removed from water by using Activated Carbon filters.      Back to Glossary

• Source - Chromium is found in drinking water as a result of discharge from pulp mills, steel mills, and erosion from natural deposits.  Proper tests should be run on the water supply to determine the form of the chromium present. Trivalent chromium (Cr=3 ) is slightly soluble in water, and is considered essential in man and animals for efficient lipid, glucose, and protein metabolism. However, hexavalent chromium (Cr=6 ) is considered toxic. The US EPA currently sets the MCL for total Chromium at .1 mg/l.
• Solution - Reverse Osmosis can effectively reduce both forms of chromium by 90 to 97%.   Hexavalent chromium (Cr+6) can be reduced by utilizing a strong base anion exchanger which must be regenerated with caustic soda. Distillation will also reduce chromium.       Back to Glossary

• Source - Color is common in surface water supplies and not very common in springs or deep wells. Stains on bathroom fixtures and laundry are often the result of natural ions like iron, manganese, and copper. A reddish color would indicate the presence of precipitated  iron.  Dark brown to black stains are created by manganese. Excess copper can create blue stains. A yellow tint to the water indicates that humic acids are present, referred to as "tannins".
• Solution - Activated Carbon filtration will work most effectively to remove color in general. Anion scavenger resin will remove tannins, but must be preceded by a softener.             Back to Glossary

• Source - Copper rarely occurs naturally in drinking water.  It is normally the result of corrosion in the water system. Copper pipes and fittings are commonly used on household plumbing.  Factors causing corrosion include acidity (low pH), high temperature, low total dissolved solids (TDS) content and high amounts of dissolved oxygen or carbon dioxide. Generally, soft water is more corrosive than hard water because it is more acidic and has low TDS. If the water is not corrosive, hard water minerals are slowly deposited on the interior of plumbing. These hard water deposits form a calcium carbonate lining inside pipes and fittings which protects against copper contamination.  However, it may take up to five years for an effective calcium carbonate lining to form. Softening hard water with an ion exchange unit can either prevent or dissolve the calcium carbonate scale, reducing it protective effect.  Too much copper can cause stomach and intestinal distress such as nausea, vomiting, diarrhea, and stomach cramps.  The US EPA has set the maximum contaminant level of copper at 1.3 mg/l.
• Solution - Copper can be reduced up to 98% through Reverse Osmosis or Distillation.  Activated Carbon filtration will also remove copper. Back to Glossary

• Source - Cryptosporidium are protozoan parasites which normally range from 3 to 5 microns in diameter. This parasite can go into cystic form which is like a hard round impermeable egg. The cyst form is resistant to chlorine and very hard to kill. When Cryptosporidium are ingested by healthy individuals, symptoms include diarrhea, fatigue, and cramps and low grade fever. However, immunocompromised individuals can have much greater reactions to infection.  The parasite can damage the liver, respiratory tract, gall bladder and pancreas.  Those with immunocompromised systems normally include infants, elderly, kidney dialysis patients, and cancer patients undergoing chemotherapy.
• Solution - Filtration is the most effective treatment for protozoan cysts. Solid block carbon for cyst reduction or pleated membrane cartridges followed by ultrafiltration or Reverse Osmosis will effectively remove Cryptosporidium cysts. Back to Glossary

• Source - Cyanide is not commonly found at significant levels in drinking water. Cyanide is normally found in waste water from discharges from steel, plastic, or fertilizer factories. The US EPA has not classified cyanide as a carcinogen because of inadequate data. The MCL level for free cyanide is .2 mg/l.
• Solution - Reverse Osmosis will remove 90 - 95 % of Cyanide. Chlorine feed, retention, and filtration will break it down. Back to Glossary

• Source - Fluoride is a naturally occurring element existing as a constituent of minerals in rocks and soil. Fluoride is also added to some public drinking water supplies at a rate of 1 mg/l to prevent tooth decay. Elevated levels of fluoride in drinking water can cause fluorosis. High levels, above those typically found in water, consumed over a long period of time can cause chronic toxicity.  The MCL established for drinking water by the US EPA is 4 mg/l.
• Solution - Fluoride can be reduced by anion exchange, reverse osmosis, distillation, or activated alumina filters. Typically these methods are used to treat water at one faucet. Reverse Osmosis will remove 93 - 95 % of the fluoride. Back to Glossary

• Source- Giardia is a protozoan which is 7 to 14 microns in size. This parasite can go into cystic form which is like a hard round impermeable egg.  The cyst form is resistant to chlorine and very hard to kill. When Giardia are ingested by healthy individuals, symptoms include diarrhea, fatigue, and cramps and low grade fever. However, immunocompromised individuals can have much greater reactions to infection.  The parasite can damage the liver, respiratory tract, gall-bladder and pancreas.  Those with immunocompromised systems normally include infants, elderly, kidney dialysis patients, and cancer patients undergoing chemotherapy.  The US EPA has set a limit of 99.9% killed/inactivated for Giardia Lamblia.
• Solution - Because of the size of the parasite, it can easily be removed with mechanical filtration.  Solid block carbon for cyst reduction or pleated membrane cartridges followed by ultrafiltration or Reverse Osmosis will effectively remove Giardia cysts. Ozone also appears to be very effective against cysts when utilized in the chemical oxidation process.            Back to Glossary

• Source - Hard water is high in dissolved minerals, specifically calcium and magnesium. As water moves through soil and rock, it dissolves very small amounts of minerals and holds them in solution. The degree of hardness becomes greater as the calcium and magnesium content increases. Hard water is not a health risk, but a problem because of mineral build up on plumbing fixtures and poor soap/detergent performance.
• Solution - Water softeners are the most economical way to handle total hardness. Softeners operate through an ion exchange  process.  In this process, water passes through a media bed, usually sulfonated polystyrene beads. The beads are saturated with sodium. The ion exchange process takes place as the hard water passes through the softening material.  The hardness minerals attach themselves to the resin beads while sodium on the resin beads is released simultaneously into the water. If the hardness is high, then the sodium will be high after softening, and may require Reverse Osmosis to make the water suitable for drinking. Back to Glossary

• Source - Sulfer reducing bacteria, which use sulfur as an energy source, are the main producers of hydrogen sulfide. The bacteria chemically change natural sulfates in water to hydrogen sulfide.  Sulfer reducing bacteria live in oxygen poor environments like plumbing systems, water softeners and water heaters.  Hydrogen sulfide gas also occurs naturally in some groundwater.  It is formed from decomposing underground deposits of organic matter like decaying plant material.  It is found in deep or shallow wells and can also enter surface water through springs. Hydrogen sulfide is also present in wells drilled in shale,  sandstone, or near coal deposits, peat deposits, or oil fields. Occasionally a hot water heater is the source of the hydrogen sulfide odor which smells like rotten eggs. The magnesium corrosion control rod present in many water heaters can react with the water to produce hydrogen sulfide.  
• Solution - Hydrogen sulfide concentrations exceeding 6ppm can be removed by injecting an oxidizing chemical such as household bleach or potassium permanganate and using a filter.  The oxidizing chemical should enter the water system upstream from the storage or mixing tank to provide at least 20 minutes of contact time between the chemical and the water.  Sulfur particles can then be removed using a sediment filter.  Excess chlorine can be removed using Activated Carbon filters. Back to Glossary

• Source - Iron can appear in several forms in a water supply.  Ferris iron will appear clear at first, but when allowed to stand it will develop black or rust colored particles that settle to the bottom of a container. Ferris iron will react with air, chlorine, or other oxidants to form the second form of iron which is Ferric iron.  This will appear rusty, red , or yellow when drawn from a faucet. Ferric iron is insoluble in water, and settles rapidly when allowed to stand in a container. Iron bacteria is the third form of iron found in water.  The appearance of iron bacteria will be a red film or brown build up on plumbing fixtures.
• Solution - Ferrous iron can be effectively treated by using a standard cation-exchange water softener. Iron is filtered from the water by the softener’s resin bed, and is removed during regeneration.  If ferrous iron levels are high, it may be necessary to convert the iron to it’s insoluble ferric state by using special oxidizing media or by chlorination.  Ferric iron can simply be removed by mechanical filtration.  Activated Carbon cartridges are commonly used for this mechanical stage to stabilize taste and odor while also removing residual  chlorine. Iron bacteria can be neutralized by using an oxidizing agent such as chlorine. This process should be followed by an Activated Carbon filter to remove excess chlorine.   Back to Glossary

• Source - Lead rarely occurs naturally in drinking water. Typically, lead contamination occurs at some point in the water delivery system when there is a reaction between water and lead in parts of the system. Materials in the delivery system which may contain lead include service connections, pipes, solder, and brass fixtures.  Too much lead in the human body can cause serious damage to the brain, kidneys, nervous system and red blood cells. Young children, infants and fetuses are especially vulnerable to lead poisoning. The US EPA has set the current action level of lead allowable in drinking water at 0.015 mg/l.
• Solution - Lead can be reduced up to 98% with a water softener followed by Reverse Osmosis or Distillation. Activated Carbon filtration can also reduce lead at the point of use.  Back to Glossary

• Source - The microorganism Legionella is found naturally in water and will multiply in heating systems. 34 people lost their lives in 1976 due to complications resulting from pneumonia.  In late 1977, it was determined the bacteria responsible for the deaths was completely different from other bacteria. The bacterium was name Legionella in honor of the American Legion convention where the original outbreak occured. Patients with legionnaire's disease often have severe gastrointestinal symptoms including diarrhea, nausea, and vomiting. The US EPA has not set a MCL (maximum contamination level) for Legionella.  They have outlined the treatment method which must be followed and the maximum contaminant level goal is      0 mg/l.
• Solution - Since Legionella is a bacteria, Reverse Osmosis or Ultrafiltration are the preferred removal techniques. Back to Glossary

• Source - Magnesium is usually about 30% of the total hardness in a particular water supply.  Magnesium is found in many minerals, including magnesite, dolomite, as well as clay. It is in abundance in sea water where it has a concentration which is five times greater than calcium. Magnesium should be removed where water is required for boiler make-up, or for process applications.
• Solution - Magnesium may be reduced to less than 1 mg/l with the use of a softener or cation exchanger in hydrogen form. Also see "Hardness". Back to Glossary

• Source - Manganese is present in soils and rocks whose structures have been changed by heat and pressure. It is used in the manufacture of steel because of its sulfur-fixing, deoxidizing and alloying properties. Manganese is a common household contaminant with no known direct health effects at levels found in drinking water. The presence of Manganese may cause staining and offensive tastes and odors similar to that of iron. The stains are dark brown to black in nature. The use of chlorine bleach in the laundry will cause the stains to set.
• Solution - Removal of manganese can be done by ion exchange with a cation water softener or chemical oxidation followed by mechanical filtration. Chemical oxidation is normally done with chlorine. Once the Manganese has been neutralized, an Activated Carbon cartridge can be used to remove excess chlorine and stabilize taste and odor. Back to Glossary

• Source - Mercury exists as an inorganic salt or an organic compound (methyl mercury). Mercury in drinking water is usually inorganic and results from erosion of natural deposits, discharge from refineries and factories, or runoff from landfills and cropland.  Organic mercury is normally found in fish and comes from industrial chemical manufacturing waste or the leaching of coal ash. Inorganic mercury will result in kidney damage if excessive amounts are ingested. On the other hand, organic mercury will affect the central nervous system. The MCL for mercury set by the US EPA is 0.002 mg/l.
• Solution - Activated Carbon filtration is very effective in the removal of mercury. Reverse Osmosis will remove 95 - 97 % of it. Back to Glossary

• Source - Methane is the primary component of natural gas. It is commonly found where land fills once existed and is generated from decaying of plants or other carbon based matter. It can also be found in and around oil fields. Methane is colorless, odorless, nearly invisible, highly flammable, and often found in conjunction with other gases such as hydrogen sulfide. Even though methane gas gives water a milky appearance, there are no known health effects.
• Solution - Aeration or degasification is the only way to eliminate the problem of methane  gas. Back to Glossary

• Source - Nickel exists in approximately 85% of water supplies and is usually around 1 ppb (part per billion). The US EPA has classified nickel as a possible human carcinogen based on inhalation exposure. Nickel has not been shown to be carcinogenic via oral exposure. There is no MCLG (maximum contamination level goal) that has been proposed at this time.
• Solution - Reverse Osmosis will remove 97 - 98 % of the nickel from drinking water. Activated Carbon filtration can also be used to reduce the amount of nickel in drinking water. Back to Glossary

• Source - Nitrogen is a nutrient applied in large quantities for lawn and garden care and crop production.  Feedlots, animal yards, septic systems, and other waste treatment systems are additional sources for nitrogen. Nitrogen occurs naturally in the soil in organic forms from decaying plant and animal residues.  Bacteria in the soil convert various forms of nitrogen to nitrate, a nitrogen/oxygen ion.  This is desirable as the majority of nitrogen used by plants is absorbed in the nitrate form.  However nitrate is highly leachable and readily moves with water through the soil.  If there is excessive rainfall or over-irrigation, nitrate will be leached below the plants root zone and may eventually reach groundwater. Nitrate in water is undetectable because it is colorless, tasteless and odorless.  A water test for nitrate is highly recommended for households with infants, pregnant women, nursing mothers, and elderly people. The MCL (maximum contaminant level) set by the EPA for nitrate in the water is 10mg/L.  The MCL level for Nitrite is 1 mg/l. 
• Solution - Nitrate can be removed from water by three methods. Reverse Osmosis, distillation, and ion exchange. It is important to note that carbon adsorptive filters, sediment filters and water softeners will not remove nitrate / nitrite. Reverse Osmosis will remove   92 - 95% of the nitrates and/or nitrites. Back to Glossary

• Source - Organics come from the breakdown of naturally occurring organic materials, commercial and domestic wastes, and chemical reactions which take place during the treatment of water.  The breakdown of naturally occurring organic materials include humic materials, microorganisms, and petroleum-based hydrocarbons. The organics coming from commercial and domestic waste are the result of wastewater discharges, agricultural runoff, urban runoff, and leaching from contaminated soils. The organics formed during water treatment include disinfection by-products such as THM's (Trihalomethanes), or undesirable components of pipe assemblies such as joint adhesive.
• Solution - Activated Carbon is generally used to remove organics. Reverse Osmosis will remove 98 to 99% of the organics in the water. Ultrafiltration and nanofiltration have also been proven to remove organics.  Back to Glossary

• Source - Pesticides are common synthetic organic chemicals (SOCs). Pesticides reach surface and well water supplies from the runoff in agricultural areas where they are used. Pesticides usually decompose and break down as they perform their intended function. Occasionally, low levels of pesticides are found where the break down has not occurred. There is no US EPA maximum contamination level (MCL) for pesticides as a total. However, certain pesticides are banned by the government because of their danger to humans or the environment.
• Solution - Activated Carbon filtration is the most effective way to remove pesticides. Reverse Osmosis will remove 97 - 99% of the pesticides. Back to Glossary

• Source - The pH scale is used to express the intensity of the acidity or alkalinity of a solution. The pH scale ranges between 0 and 14. Acidic [ 0 ]=========[ 7 ]==========[ 14 ] Alkaline . A pH of 7 is considered neutral. Typically all natural waters fall within the range of 6.0 to 8.0 pH. The lower the pH, the more corrosive the water.  Waters with less than 6.8 pH contain sufficient acidity to cause significant corrosion and should be treated.
• Solution - The pH can be raised by feeding alkaline materials into the system. This is most often accomplished by adding a neutralizing filter, which contains minerals that will react with the acidity to raise the pH. This process slowly dissolves the minerals and adds a few grains of hardness to the water.  Because of the increased hardness it is usually necessary to install a water softener after the feed system.  In some cases, for use with an electrically operated well or water pump, a chemical solution pump can be used to feed a solution of acid neutralizer into the water system. Back to Glossary

• Source - Potassium is an alkaline metal closely related to sodium. It is normally not tested alone in water analysis. Potassium is not a major part of public or industrial water supplies. It is however, necessary in a well balanced diet.
• Solution - Potassium can be removed by a water softener. Reverse Osmosis can also reduce Potassium by 94 - 97%.  Back to Glossary

• Source - Radium is a radioactive chemical which occurs as a result of erosion of natural deposits or man made contamination.  It is used in the treatment of cancer and some skin diseases. Radium 226 and 228 are of most concern when found in drinking water because of the effects on the health of individuals. Radium 228 causes bone sarcomas. Radium 226 induces carcinomas in the head.  A picocurie (pCi) equals 10-12 curies. The US EPA has set the MCL for radium 226 and 228 at 5 pCi/L 
• Solution - Radium can be removed using a water softener or by Reverse Osmosis.  RO will typically remove 95 - 98% of any radioactivity in drinking water. Back to Glossary

• Source - Radon is a radioactive gaseous element formed when radium breaks down. Radon 222 is most alarming when found in drinking water. It is naturally occurring, but can also come from man-made sources. All radionuclides are considered carcinogens, but they can attack various organs.  For example Radon 222 is a gas and can therefore be inhaled during showers or while washing dishes. There is a direct relationship between radon 222 and lung cancer. The present maximum contamination level for Radon 222 is set at 15 pCi/L.  A picocurie (pCi) equals 10-12 curies.
• Solution - Activated Carbon filtration is effective in removing radon as well as aeration. Back to Glossary

• Source - Selenium is essential for human nutrition. The level found in drinking water is usually low, and results from discharging from petroleum refineries, mines, or erosion of natural deposits. Naturally occurring selenium compounds have not been shown to be carcinogenic in animals. The US EPA has set the MCL for selenium at 0.05 mg/l.
• Solution - Reverse Osmosis is an excellent way to reduce selenium. Anion exchange can also be used to reduce selenium in drinking water by 60 - 95%. Back to Glossary

• Source - Silica is present in almost all minerals and found in surface and well water in the range of 1 - 100 mg/l. Silica is gel type contaminant which will remain suspended in fluid streams. Silica presents problems in cooling tower and boiler feedwaters because it will evaporate at high temperatures and then form again on turbine blades.  These deposits must be periodically removed or they will damage the turbine. Silica is not listed in the Primary or the Secondary Drinking Water Standards issued by the US EPA.
• Solution - Reverse Osmosis will reject 85 - 90% of the silica content in the water.  Silica may also be removed by the anion exchange portion of a demineralization process.         Back to Glossary

• Source - Silver is a white metallic chemical element found in natural water supplies. Chronic exposure to silver results in a blue-gray color of the skin. This is a permanent aesthetic effect. Silver shows no evidence of carcinogenicity.   The MCL set by the US EPA for silver is       0.1 mg/l
• Solution - Silver can be reduced by 98% with distillation, up to 90% by Reverse Osmosis,  up to 90% with cation exchange or anion exchange, or up to 60% with Activated Carbon filtration. Back to Glossary

• Source - Over 1000 SOCs  have been detected in drinking water. Most are considered harmless, but some do pose a health risk.  Below is a list of some synthetic organic chemicals along with the proposed MCL (maximum contamination level) in mg/l as determined by the US EPA Primary Drinking Water Regulations.

• Solution - Reverse Osmosis will remove 98 to 99% of organics in water. Activated Carbon, ultrafiltration and nanofiltration have also been proven to remove organics.         Back to Glossary

• Source - Sodium is present to some degree in all water supplies. The amount is dependent on local soil conditions. The higher the sodium content of water, the more corrosive the water becomes. Intake from food is generally the major source of sodium in a persons diet, ranging from 1100 to 3300 mg/day.  The amount of sodium obtained from drinking softened water is insignificant compared to the sodium ingested in the normal human diet. Sodium chloride is essential in the formation of stomach acids which are necessary for the digestive process. The US EPA has concluded that there is no relationship between soft water and cardiovascular disease. There is no MCL published for sodium, however the US EPA suggests a level of 20 mg/l in drinking water for that portion of the population on severe sodium restricted diets of 500 mg/day or less.
• Solution - Sodium can be removed through Reverse Osmosis, distillation or demineralization. Back to Glossary

• Source - Strontium is similar to calcium and magnesium and will show up as hardness in the water. It is normally found in low concentrations where there are lead ores present.  Strontium sulfate will foul reverse osmosis membranes if the concentration is high enough. There is no MCL for strontium listed in the US EPA Drinking Water Standards.
• Solution - Strontium can be removed with strong acid cation exchange resin. Reverse Osmosis will also reduce strontium but is not recommended because the RO membrane could foul prematurely. Back to Glossary

• Source - Sulfates are a combination of sulfur and oxygen. They are a part of naturally occurring minerals in some soil and rock formations that contain groundwater. The mineral is dissolved over time and released into groundwater. Sulfur minerals can cause scale build up in water pipes and may be associated with a bitter taste in water.  They can also have a laxative effect on humans and livestock.
• Solution - For small quantities (cooking and drinking water) you may use either Reverse Osmosis or distillation.  For larger quantities, the most common method is ion exchange.  This process works similar to a water softener. Ion exchange resin, contained inside the unit, adsorbs the sulfate. When the resin is loaded to full capacity with sulfate, the treatment stops. The resin must then be regenerated with a sodium chloride brine solution before further treatment can occur. Back to Glossary

• Source - Poor taste and foul odor are generally considered as the same problem, except for taste caused by high mineral salts.  An example of this is water with a high chloride content will taste salty but remain odorless.  Quality water should have no trace of objectionable taste or odor. There are a variety of tastes and odors which may exist in a water supply. Some common examples are chlorine odor, musty/moldy taste or odor, oil or gas odor, and rotten egg odor.   
• Solution - Each taste or odor problem represents distinct problems and treatments.  Activated Carbon has an excellent history of success in treating chlorine, must & mold, and oil or gas odors.  The life of the carbon depends on the amount of organics competing for sites and the concentration of the taste and odor causing compound. Rotten egg odors are normally caused by dissolved hydrogen sulfide gas. Please refer to the section which discusses Hydrogen Sulfide for treatment of this odor. Back to Glossary

• Source - Total dissolved solids are the sum of all mineral compounds dissolved in water. They consist primarily of calcium, magnesium, or sodium in the form of chlorides, sulfates, or bicarbonates.  Excessive dissolved solids decrease the effectiveness of a water softener.  While softening will greatly improve water for many things in a household, high TDS content will exhibit a salty or brackish taste.  The chart below indicates the TDS from various  sources.

High levels of total dissolved solids can adversely affect industrial applications such as cooling tower operations, boiler feed water, food and beverage, and electronics. High levels of chloride and sulfate will accelerate corrosion of metals. The US EPA has a suggested level of 500 mg/l listed in the Secondary Drinking Water Standards.

• Solution - Reducing the amount of TDS in water can be accomplished through distillation, Reverse Osmosis, or demineralization. Back to Glossary

• Source - Trihalomethanes are produced when chlorine reacts with residual organic compounds in the chlorination process. The four common THM's are chloroform, dibromochloromethane, dichlorobromomethane, and bromoform. There have been studies linking trihalomethanes with increased risk for bladder and rectal cancer. The EPA has set the MCL of THM’s at 0.10 mg/l.
• Solution - Trihalomethanes and can be reduced by using an Activated Carbon filter.     Back to Glossary

• Source - Organic contaminants (natural organic substances, insecticides, herbicides, and other agricultural chemicals) enter the waterways in rainfall runoff.  Domestic and industrial wastewaters also contribute organic contaminants in various amounts. Industrial organic waste may enter streams as a result of accidental spills or leaks. The TOC test is the most common test performed to obtain an indication of the organic content in water. The organic content of the water will appear on the water analysis as C (carbon). 
• Solution - Reverse Osmosis will remove 98 to 99% of the organics in the water. Activated Carbon, Ultrafiltration and nanofiltration have also been proven to remove organics.       Back to Glossary

• Source - Turbidity (fine particles) and sediment (coarse particles) may be caused by sand, scale, rust, organic matter, or clay.  In addition to a cloudy appearance, these substances may cause plugged piping or fouled water equipment.  Turbidity does not settle out quickly, but remains suspended for several hours. It is normally present in pond, lake, or river water supplies.  Turbidity levels should be less than 5 NTU’s (turbidity units) for clear acceptable water.  
• Solution - Turbidity can be reduced to by a variety of mechanical methods. Since turbidity is usually present with other water contaminants, it is recommended to test the water to find out what the other contaminants may exist. Normally turbidity will be reduced through the use of sediment filter cartridges followed by activated carbon cartridges. Back to Glossary

• Source - Uranium is a naturally occurring radionuclide. Natural uranium combines uranium 234, uranium 235, and uranium 238. Uranium 238 makes up over 90% of the radionuclide we have found. Uranium is not a proven carcinogen but accumulates in the bones similar to the way radium does. Because of this, the US EPA tends to classify it as a carcinogen. Uranium has been found to have a negative effect on human kidneys. The MCL  for uranium is set at 30 ug/L. A picocurie (pCi) equals 10-12 curies.
• Solution - Reverse Osmosis will reduce uranium by 95 to 98%. Uranium can also be reduced by anion or cation exchange as well as activated alumina. Back to Glossary

• Source - Viruses are infectious organisms which range in size from 10 to 25 nanometers.  They normally come from human and animal fecal waste.  Viruses depend totally on living cells and lack an independent metabolism. There are over 100 types of enteric viruses which are the type that infect humans. Enteric viruses finding there way into into drinking water are Hepatitis A, Norwalk-type viruses, Rotaviruses, Adenoviruses, Enteroviruses, and Reoviruses. Since most municipalities test for coliform bacteria as an indicator of safe drinking water, they usually will not run a separate test for viruses. The US EPA has established an MCL which states a level of  99.99% killed/inactivated for viruses. Major enteric viruses and their diseases are listed below.

• Solution - Chlorine feed with 30 minute contact time, followed by Activated carbon filtration is the most widely used treatment.  Ultraviolet sterilization or distillation may also be used for the treatment of viruses. Back to Glossary

• Source - VOC’s are chemicals that are colorless, odorless, and tasteless.  They include pesticides, herbicides,  as well as other chemicals. Some of the VOC’s regulated under the Safe Drinking Water Act of 1986 are listed below.

• Solution - The best choice for removal of volatile organic chemicals is Activated Carbon filtration. The adsorption capacity of the carbon will vary with each type of VOC. Reverse Osmosis will remove 70 to 80% of the VOCs in water. Ultrafiltration is also capable of reducing volatile organic chemicals. Back to Glossary

Copyright  H.R.Peterson 2017

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