Water Terms and Definitions

MILLIGRAMS PER LITER, mg/L A measure of the concentration by weight of a substance per unit volume. If one Liter of water contains 10 milligrams of calcium then it would contain 10 mg/L. This is the same as parts per million, ppm, since there are 1000 milligrams in a gram, and 1000 grams of water in a Liter. Most of our test results are reported in milligrams per liter. MAXIMUM CONTAMINANT LEVEL, (MCL) The largest allowable amount. MCLs for various water quality indicators are specified by the Utah Division of Drinking water. MINIMUM DETECTABLE LEVEL, (MDL) The smallest level of substance that can be detected by a test. M.F.L. Millions of Fibers per Liter; Used to report Asbestos testing results. The limit of detection (LOD) for the method used has been determined to be one asbestos fiber in the total number of grid openings analyzed. The number of openings analyzed is dependent on the sample volume filtered (4 minimum). ACTIVATED CARBON Adsorptive particles or granules of carbon usually obtained by heating carbon (such as wood). These particles or granules have a high capacity to selectively remove certain trace and soluble materials from water. AERATION The process of adding air to water. Air can be added to water by either passing air through water or passing water through air. ALKALINITY The capacity of water to neutralize acids. This capacity is caused by the water's content of carbonate, bicarbonate, hydroxide, and occasionally borate, silicate, and phosphate. Alkalinity is not the same as pH because water does not have to be strongly basic (high pH) to have a high alkalinity. Alkalinity is a measure of how much acid can be added to a liquid without causing a great change in pH. BACK FLOW A reverse flow condition, created by a difference in water pressures, which causes water to flow back in to the distribution pipes or a potable water supply from any source or sources other than an intended source. BACKSIPHONAGE A form of back flow caused by a negative or below atmospheric pressure within a water system. BACTERIA Bacteria are living organisms, microscopic in size, which usually consist of a single cell. Most bacteria use organic matter for their food and produce waste products as a result of their life processes. CHECK VALVE A special valve with a hinged disc or flap that opens in the direction of normal flow and is forced shut when flows attempt to go in the reverse or direction opposite the normal flow. CHLORINATION The application of chlorine to water, generally for the purpose of disinfection, but frequently for accomplishing other biological or chemical results (aiding coagulation and controlling tastes and odors). CONVENTIONAL FILTRATION A method of treating water which consists of the addition of coagulant chemicals, flash mixing, coagulation-flocculation, sedimentation and filtration. Also called complete filtration. CROSS CONNECTION A connection between a drinking (potable) water system and an unapproved water supply. For example, if the water pressure in the distribution system were to drop lower than the pressure in your home, it could pull your water back into the system. Anywhere there is a possibility of contamination from unapproved waters is considered a cross connection, and proper protection devices (back flow devices or assemblies) are required. DISINFECTION The process designed to kill most microorganisms in water, including essentially all pathogenic (disease-causing) bacteria. There are several ways to disinfect, with chlorine being the most frequently used in water treatment. FLOCCULATION The gathering together of fine particles after coagulation to form larger particles by a process of gentle mixing. HARDNESS, WATER A characteristic of water caused mainly by the salts of calcium and magnesium, such as bicarbonate, carbonate, sulfate, chloride and nitrate. Excessive hardness in water is undesirable because it causes the formation of soap curds, increased use of soap, deposition of scale in boilers, damage in some industrial processes, and sometimes causes objectionable tastes in drinking water. INORGANIC Material such as sand, salt, iron, calcium salts and other mineral materials. Inorganic substances are of mineral origin, whereas organic substances are usually of animal or plant origin. INSECTICIDE Any substance or chemical formulated to kill or control insects. MGD Million Gallons a Day - a term used when referring to large amounts of water. ORGANICS Substances that come from animal or plant sources. Organic substances always contain carbon. (Inorganic materials are chemical substances of mineral origin.) PATHOGENIC ORGANISMS Organisms, including bacteria, viruses or cysts, capable of causing diseases (typhoid, cholera, dysentery) in a host (such as a person). There are many types of organisms which do NOT cause disease. These organisms are called nonpathogenic. POLLUTION The impairment (reduction) of water quality by agricultural, domestic, or industrial wastes (including thermal and atomic wastes). POLYMER A chemical formed by the union of many monomers (a molecule of low molecular weight). Polymers are used with other chemical coagulants to aid in binding small suspended particles to larger chemical floc for their removal from water. All are polymers, but not all polymers are polyelectrolyte. POTABLE WATER Water that does not contain objectionable pollution, contamination, minerals, or infective agents and is considered satisfactory for drinking. SEDIMENTATION A water treatment process in which solid particles settle out of the water being treated in a large clarifier or sedimentation basin. TDS Total Dissolved Solids VOC ( Volatile Organic Chemicals ) A volatile substance is one that is capable of being evaporated or changed to a vapor at relatively low temperatures. In terms of solids, volatile refers to materials lost (including most organic matter) upon ignition in a muffle furnace for 60 minutes at 550° C. Natural volatile materials are chemical substances usually of animal or plant origin. Manufactured or synthetic volatile materials such as ether, acetone, and carbon tetrachloride are highly volatile and not of plant or animal origin.