Definitions in water treatment

A substance that has a pH of less than 7, which is neutral. Specifically, an acid has more free hydrogen ions (H+) than hydroxyl ions (OH-).

Acid Rain is rain that has been made acidic by certain pollutants released in the air, most commonly caused by human activities. Acid rain creates tiny particles which can easily enter people's lungs and cause health problems, especially those with difficulty breathing. Lastly, acid rain damages lakes and streams by increasing the acidity in water which can be deadly to aquatic wildlife.

Sometimes water or soils contain an amount of alkali (strongly basic) substances sufficient to raise the pH value above 7.0 and be harmful to the growth of crops.

The capacity of water for neutralizing an acid solution.

An abundant metallic chemical widely used throughout the world for a wide range of products. Aluminum is a malleable metal commonly used to make soda cans. It is the third most common element in the Earth's crust and is the most common metallic element on Earth. Aluminum in drinking water is said to be associated with Alzheimer's disease because the aluminum could damage nerve cells and their connectors.

An odorless and tasteless chemical element commonly used to strengthen alloys of copper and especially lead. Arsenic poisoning can occur when arsenic is consumed in high concentrations in drinking water. The EPA has set the standard for drinking water at 0.010 parts per million to protect consumers from the long term, chronic effects of arsenic. Arsenic has been linked to cancer of the bladder, lungs, skin, kidney, liver and more.

A set of six naturally occurring silicate minerals used commercially for their desirable physical properties. Asbestos is useful because of its sound absorption, strength, and its resistance to heat and electrical damage. Exposure to asbestos fibers increase your risk of developing lung disease. Asbestos used to be used in homes as fire proofing, roofing, and flooring but most products made today do not contain asbestos.

A single cell microorganism which can exist either as an independent organism or upon another organism for life. Bacteria can cause disease, spoil food, and contaminate water. The transmission of disease through drinking water can occur when drinking water has been contaminated by human or animal waste.

The amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. BOD can be used to gauge the effectiveness of wastewater treatment plants.

A minor metallic element naturally occurring in the earth's crust and waters. Cadmium used to be used as a pigment for corrosion resistant plating on steel while cadmium compounds were used to stabilize plastic. Now cadmium is used less and less due to competing technologies. Exposure to certain forms and concentrations of cadmium is known to produce toxic effect on humans.

The most abundant mineral in the human body stored mostly in our bones and teeth. The body constantly breaks down and rebuilds the bones, however the older the body gets it tends to reabsorb more calcium than it returns leading to osteoporosis. Calcium is found in milk, cheese, yogurt, dark green vegetables, but more importantly your body needs Vitamin D to be able to absorb the calcium.

Chemicals that are a compound or substance that is used or results from a reaction involving changes to atoms or molecules. Chemicals exist as solids, liquids, gases, or plasma and may change between these phases of matter with changes in temperature or pressure. Drinking water is often contaminated with toxic chemicals and need to be filtered or it can cause severe illness over time.

A yellow-green gas with a pungent, irritating odor similar to bleach. Chlorine can be pressurized and cooled to change into a liquid form. Chlorine is used to disinfect pools, used as bleach in the manufacture of paper and cloth, and used to make pesticides and solvents. Chlorine is used in drinking water to kill harmful bacteria but overtime the continuous consumption of low levels of chlorine can cause serious health problems.

A steel-like gray, odorless, tasteless, hard metal that takes a high polish and has a high melting point. Chromium is known for its high corrosion resistance, hardness, and remarkable magnetic properties. Chromium compounds bind to soil and eventually contaminate drinking water. Health effects include skin irritation, ulceration, and liver and kidney damage.

Coliform is a type of bacteria that is present in the environment and in the feces of all warm-blooded animals and humans. Coliforms themselves do not cause serious illness but are rather used as an indicator of sanitary quality of foods and water. If coliform bacteria are found in your drinking water your water system it should be inspected to find and eliminate any other sources of contamination.

Water used for motels, hotels, restaurants, office buildings, other commercial facilities, and institutions. Water for commercial uses comes both from public-supplied sources, such as a county water department, and self-supplied sources, such as local wells.

A malleable metallic element used in large quantities as an electrical conductor such as brass and bronze. Copper is often found in drinking water because of the corrosion of water pipes and can cause short- and long-term illness.

When a material deteriorates due to interaction with the environment. Dissimilar metal, oxygen, water, and debris can all cause corrosion. For example, when the pH of water is lower than 8, copper oxide no longer creates a barrier in the pipe and causes the pipe to corrode. This can be harmful to health because corroded particles may enter the drinking water supply.

The process used to remove all salts from water. The first step removes the calcium and magnesium ions, and in the process replaces them with hydrogen ions instead of sodium. The second step is an anion exchange where the negative ions (anions) are absorbed into the anion exchange and release hydroxyl anions. The result of this two steps ion exchange is mineral free water.

The removal of salts from saline water to provide freshwater. This method is becoming a more popular way of providing freshwater to populations.

Water that has many of its impurities removed through distillation. Distillation is the process of boiling water which condensates the clean water into a container leaving a broad range of contaminants behind. Distillation's disadvantage is that it requires a large amount of energy and water which can be costly.

Water used for household purposes, such as drinking, food preparation, bathing, washing clothes, dishes, and dogs, flushing toilets, and watering lawns and gardens. About 85% of domestic water is delivered to homes by a public-supply facility, such as a county water department. About 15% of the Nation's population supply their own water, mainly from wells.

Water that flows from a sewage treatment plant after it has been treated.

A state of rest or balance due to the equal action of opposing forces. Drinking more water can bring the body's functions back to equilibrium and help your body rid problems of water retention.

The process of liquid water becoming water vapor, including vaporization from water surfaces, land surfaces, and snow fields, but not from leaf surfaces. See transpiration

Water that has been purified to prevent scale deposit or corrosion and is supplied to a generator to be converted into steam.

A well or spring that taps ground water under pressure so that water rises without pumping. If the water rises above the surface, it is known as a flowing well.

Fluoride is naturally present in many drinking water sources and is said to prevent levels of tooth decay. However, the controversy over fluoride in water supply states that long time exposure has been demonstrated to have effects on skeletal and bone tissues. This is why it is important to get your water levels tested to see the amount of fluoride and other contaminants present in the water.

Water that contains less than 1,000 milligrams per liter (mg/L) of dissolved solids; generally, more than 500 mg/L of dissolved solids is undesirable for drinking and many industrial uses.

Wastewater from clothes washing machines, showers, bathtubs, hand washing, lavatories and sinks.

Water that flows or seeps downward and saturates soil or rock, supplying springs and wells. The upper surface of the saturate zone is called the water table. Water stored underground in rock crevices and in the pores of geologic materials that make up the Earth's crust.

A water-quality indication of the concentration of alkaline salts in water, mainly calcium and magnesium. If the water you use is "hard" then more soap, detergent or shampoo is necessary to raise a lather.

water used for industrial purposes in such industries as steel, chemical, paper, and petroleum refining. Nationally, water for industrial uses comes mainly (80%) from self-supplied sources, such as a local wells or withdrawal points in a river, but some water comes from public-supplied sources, such as the county/city water department.

Iron is one of the most abundant metals on earth, and is an essential mineral to the human body health. Iron's main function is to carry oxygen from our lungs throughout our body. Iron deficiency in our body can cause many health issues and is the leading cause of anemia. Iron is also used as a common metal to build automobiles, machine tools, large ships and many more.

The controlled application of water for agricultural purposes through manmade systems to supply water requirements not satisfied by rainfall.

Water application on lands to assist in the growing of crops and pastures or to maintain vegetative growth in recreational lands, such as parks and golf courses.

The process by which soluble materials in the soil, such as salts, nutrients, pesticide chemicals or contaminants, are washed into a lower layer of soil or are dissolved and carried away by water.

Lead is a soft malleable metal in the carbon group and is counted as one of the heavy metals. The most important use of lead is in the manufacture of lead-acid storage batteries, commonly used in a car battery. Lead is sometimes used in household plumbing which allows water to easily be contaminated with the metal. Lead consumption has short term and long-term health effects and should be filtered out with a water filtration system before water is suitable to drink.

A chemical element which is known as an alkaline earth metal abundant in earth's crust. Magnesium is found in the body where it is stored half in the bones and half in the other organs and cells and is crucial for normal muscle and nerve function. Magnesium is also related to strong bones and a healthy immune system.

A chemical element with important industrial metal uses, particularly in stainless steel. Manganese is also present in tiny amounts in the body and serves to help the body form connective tissue, bone, blood clotting, carbohydrate metabolism, calcium absorption, and blood sugar regulation. When manganese is found in water it produces extremely dark stains and causes deposit to collect in the pipes. Light concentrations of manganese in water can be removed by a water softener and higher concentrations may be removed by oxidizing filters.

A heavy silvery element that is the only metal that is liquid at standard conditions for temperature and pressure. Mercury is used in thermometers, barometers, manometers, and other scientific apparatus. Mercury is typically released from industrial processes, agricultural processes, or commercial and medical products and can enter drinking water systems. High levels of mercury consumption can cause kidney damage.

A unit of the concentration of a constituent in water or wastewater. It represents 0.001 gram of a constituent in 1 liter of water. It is approximately equal to one part per million (PPM).

A natural occurring solid chemical substance formed through biogeochemical processes with a crystalline structure. Minerals help your body with many different functions and are essential in growth and maintaining health.

A water system that has at least five service connections or which regularly serves 25 individuals for 60 days; also called a public water system

A chemical that can be found in some public or private drinking water supplies. Nitrates are oxygen chemical units which combine with other various organic and inorganic compounds. Once taken into the body, nitrates are converted into nitrites. The greatest use of nitrates is as a fertilizer. Nitrates are very soluble and do not bind to soil and are likely to to remain in water until consumed by plants or other organisms.

A chemical that an organism needs in order to live and grow. Nutrients are used to build and repair tissues, regulate body processes, and are used to convert and use energy in the body. Some nutrients include carbohydrates, fats, proteins, and vitamins. It is best to consume the most natural nutrients as well as a variety of nutrients and not just the same kind.

Plant and animal residues, or substances made by living organisms. All are based upon carbon compounds.

The movement of water molecules through a thin membrane. The osmosis process occurs in our bodies and is also one method of desalinating saline water.

The combination of a substance with oxygen. A reaction in which atoms in an element lose electrons and the valence of the element is correspondingly increased. The liver eliminates 90-95% of the alcohol by oxidation of the alcohol to carbon dioxide and water.

The need for molecular oxygen to meet the needs of biological and chemical processes in water. Even though very little oxygen will dissolve in water, it is extremely important in biological and chemical processes.

The diameter, in millimeters, of suspended sediment or bed material.

The number of "parts" by weight of a substance per million parts of water. This unit is commonly used to represent pollutant concentrations.

A disease-producing agent; usually applied to a living organism. Generally, any viruses, bacteria, or fungi that cause disease.

The maximum instantaneous discharge of a stream or river at a given location. It usually occurs at or near the time of maximum stage.

The ability of a material to allow the passage of a liquid, such as water through rocks. Permeable materials, such as gravel and sand, allow water to move quickly through them, where an non permeable material, such as clay, don't allow water to flow freely.

Chemicals, biological agents, antimicrobials, or disinfectants that are designed to repel, control, attract, and then terminate pests. Pests include insects, weeds, birds, mammals, fish, and more. Pesticides are one of the causes of water pollution, and some of the pesticides are persistent organic pollutants which can contribute to soil pollution.

A measure of the relative acidity or alkalinity of water. Water with a pH of 7 is neutral; lower pH levels indicate increasing acidity, while pH levels higher than 7 indicate increasingly basic solutions.

pH is a measure of the acidity or alkalinity of an aqueous solution and is a good indicator of whether water is hard or soft. Pure water is said to be at a pH of 7, pH lower than 7 is said to be acidic and greater than 7 is considered alkaline. The measure of pH and alkalinity is needed to determine the corrosiveness of water.

An inorganic material which is found in many foods and preservatives. Phosphates are often used to prevent scale formation and corrosion (Iron & Manganese) in water distribution systems. It is also used to reduce lead and copper in drinking water. Studies have shown that high levels of phosphate in the body have been linked to cardiovascular disease and other health issues.

When the unit is installed on your main water line to purify all the water in your home. Unlike the point of use, which is where water is purified only on a single faucet.

A measure of the water-bearing capacity of subsurface rock. With respect to water movement, it is not just the total magnitude of porosity that is important, but the size of the voids and the extent to which they are interconnected, as the pores in a formation may be open, or interconnected, or closed and isolated. For example, clay may have a very high porosity with respect to potential water content, but it constitutes a poor medium as an aquifer because the pores are usually so small.

Water of a quality suitable for drinking.

Potassium is an important mineral to the normal functioning of your body and works with other minerals to keep the body's water level balanced. Potassium levels in the body are regulated by the kidneys and excess potassium is excreted in the urine to maintain balance.

The first stage of the wastewater-treatment process where mechanical methods, such as filters and scrapers, are used to remove pollutants. Solid material in sewage also settles out in this process.

A family or individual's personal access to water that comes from a well. EPA does not have the authority to regulate the water quality of private water wells which can cause hazardous health issues because the water may be contaminated.

Water supplied from a public-water supply and used for such purposes as firefighting, street washing, and municipal parks and swimming pools.

Water from any source that is physically processed to remove impurities. Drinking water is expected to have contaminants that can cause several problems over time. Which makes it important to have access to purified water in order to avoid these contaminants and protect your health.

A naturally occurring silvery-white radioactive material that can exist in several forms called isotopes found in soil, rocks, plants, and foods at low levels. Surface water is generally low in radium but groundwater can contain significant amounts. Most people are exposed to radium levels daily and it is insignificant to their health, however high levels of exposure can lead to tissue and bone cancer.

Water that is used more than one time before it passes back into the natural hydrologic system.

A pond, lake, or basin, either natural or artificial, for the storage, regulation, and control of water.

(Desalination) The process of removing salts from water using a membrane. With reverse osmosis, the product water passes through a fine membrane that the salts are unable to pass through, while the salt waste (brine) is removed and disposed. This process differs from electrodialysis, where the salts are extracted from the feedwater by using a membrane with an electrical current to separate the ions. The positive ions go through one membrane, while the negative ions flow through a different membrane, leaving the end product of freshwater.

A natural stream of water of considerable volume, larger than a brook or creek.

Reverse osmosis permeates, the point at which the water flows through the pores of the membrane to remove chlorine, dust, rust, and other particles.

Water that contains significant amounts of dissolved solids, The parameters for saline water:

Fresh water; Less than 1,000 parts per million (ppm)

Slightly saline water; From 1,000 ppm to 3,000 ppm

Moderately saline water; From 3,000 ppm to 10,000 ppm

Highly saline water - From 10,000 ppm to 35,000 ppm

It is the amount of salt dissolved in the water. The higher the salinity the more salt.

Hard water is known to leave behind scale deposits on dishes, sinks, toilets, etc. Scale deposits are composed mainly of calcium and magnesium. The buildup of these deposits can restrict the flow of water in pipes over time. This is why it is often preferred to use soft water to prevent the damages due from scale deposits.

Treatment (following primary wastewater treatment) involving the biological process of reducing suspended, colloidal, and dissolved organic matter in effluent from primary treatment systems and which generally removes 80 to 95 percent of the Biochemical Oxygen Demand (BOD) and suspended matter. Secondary wastewater treatment may be accomplished by biological or chemical-physical methods. Activated sludge and trickling filters are two of the most common means of secondary treatment. It is accomplished by bringing together waste, bacteria, and oxygen in trickling filters or in the activated sludge process. This treatment removes floating and settleable solids and about 90 percent of the oxygen-demanding substances and suspended solids. Disinfection is the final stage of secondary treatment.

Usually applied to material in suspension in water or recently deposited from suspension. In the plural the word is applied to all kinds of deposits from the waters of streams, lakes, or seas.

Wastewater tanks in which floating wastes are skimmed off and settled solids are removed for disposal.

A tank used to detain domestic wastes to allow the settling of solids prior to distribution to a leach field for soil absorption. Septic tanks are used when a sewer line is not available to carry them to a treatment plant. A settling tank in which settled sludge is in immediate contact with sewage flowing through the tank, and wherein solids are decomposed by anaerobic bacterial action.

An open lagoon into which wastewater contaminated with solid pollutants is placed and allowed to stand. The solid pollutants suspended in the water sink to the bottom of the lagoon and the liquid is allowed to overflow out of the enclosure.

A facility designed to receive the wastewater from domestic sources and to remove materials that damage water quality, the substances removed are classified into four basic areas:

[1] greases and fats;

[2] solids from human waste and other sources;

[3] dissolved pollutants from human waste and decomposition products; and

[4] dangerous microorganisms.

Most facilities employ a combination of mechanical removal steps and bacterial decomposition to achieve the desired results. Chlorine is often added to discharges from the plants to reduce the danger of spreading disease by the release of pathogenic bacteria.

A system of underground pipes that collect and deliver wastewater to treatment facilities or streams.

A compound containing a silicon bearing anion, known to be present in all living organisms. The earth's crust contains 80-90% silicates as well as other compounds. Water moving over natural deposits will dissolve a small amount of silicate minerals, making silicates a common contaminant of most waters. Silicon is found in products such as detergent, stoneware, wood, cement, etc.

Sodium is a major mineral necessary to regulate blood pressure and fluid volume. It is also important in maintaining the balance of pH levels. Sodium is essential in the body but must not be taken in excess amounts. The more sodium you consume, the more water your body will retain which can result in bloating and high blood pressure.

Also known as washing soda or soda ash, is a sodium salt of carbonic acid. It is known for its everyday use as a water softener. Sodium Carbonate is also used as a pH regulator to maintain stable alkaline conditions.

The sodium salt of sulfuric acid (Na2SO4), the most important mineral in the chemicals industry. Sodium sulfate is used to make soaps, detergents, glass, and paper.

Water treated in which the only ion is sodium. In comparison to hard water, soft water contains less calcium and other deposits. It may taste salty but is preferred in homes because it does not damage sinks and faucets with deposits as hard water is known to do. A great advantage of soft water is that it is known to save users money because it requires less soap when showering or washing clothes. Soft water is also known to leave less film deposits on dishes and bathroom areas.

A mixture of a solvent and a solute. In some solutions, such as sugar water, the substances mix so thoroughly that the solute cannot be seen. But in other solutions, such as water mixed with dye, the solution is visibly changed.

A water body formed when the side of a hill, a valley bottom or other excavation intersects a flowing body of groundwater at or below the local water table, below which the subsurface material is saturated with water.

A sewer that carries only surface runoff, street wash, and snow melt from the land. In a separate sewer system, storm sewers are completely separate from those that carry domestic and commercial wastewater (sanitary sewers).

A general term for a body of flowing water; natural water course containing water at least part of the year. In hydrology, it is generally applied to the water flowing in a natural channel as distinct from a canal.

Water that is on the Earth's surface, such as in a stream, river, lake, or reservoir.

Very fine soil particles that remain in suspension in water for a considerable period of time without contact with the bottom. Such material remains in suspension due to the upward components of turbulence and currents and/or by suspension.

The ratio of the mass of dry sediment in a water-sediment mixture to the mass of the water-sediment mixture. Typically expressed in milligrams of dry sediment per liter of water-sediment mixture.

Solids that are not in true solution and that can be removed by filtration. Such suspended solids usually contribute directly to turbidity. Defined in waste management, these are small particles of solid pollutants that resist separation by conventional methods.

Selected biological, physical, and chemical separation processes to remove organic and inorganic substances that resist conventional treatment practices; the additional treatment of effluent beyond that of primary and secondary treatment methods to obtain a very high quality of effluent. The complete wastewater treatment process typically involves a three-phase process: (1) First, in the primary wastewater treatment process, which incorporates physical aspects, untreated water is passed through a series of screens to remove solid wastes; (2) Second, in the secondary wastewater treatment process, typically involving biological and chemical processes, screened wastewater is then passed a series of holding and aeration tanks and ponds; and (3) Third, the tertiary wastewater treatment process consists of flocculation basins, clarifiers, filters, and chlorine basins or ozone or ultraviolet radiation processes.

The measure of the combined content of all inorganic and organic substances. The principle use of TDS is in the application of water quality for streams, rivers, and lakes to indicate the presence of chemical contaminants in the water. Primary sources of TDS in water come from natural sources, sewage, urban run-off, industrial wastewater, and chemicals used in the water treatment process. A high concentration of TDS does not pose a health risk but it does affect the aesthetic quality of the water, interfere with washing clothes and corroding plumbing fixtures.

Organic chemical that often occurs in drinking water as a result of chlorine treatment for disinfectant purposes, therefore known as disinfection byproducts. Trihalomethanes are environmental pollutants and are considered cancer causing. THMs may be absorbed into the body by inhalation, ingestion, and through the skin.

The amount of solid particles that are suspended in water and that cause light rays shining through the water to scatter. Thus, turbidity makes the water cloudy or even opaque in extreme cases. Turbidity is measured in nephelometric turbidity units (NTU).

Water that has been used in homes, industries, and businesses that is not for reuse unless it is treated.

The circuit of water movement from the oceans to the atmosphere and to the Earth and return to the atmosphere through various stages or processes such as precipitation, interception, runoff, infiltration, percolation, storage, evaporation, and transportation.

Disease caused by pathogenic microorganisms which are directly transmitted when contaminated fresh water is consumed. Water borne diseases are spread by contamination of drinking water systems with the urine and feces of infected animal or people. This is likely to occur from runoff from landfills, septic fields, sewer pipes, or any surface water.

A term used to describe the chemical, physical, and biological characteristics of water, usually in respect to its suitability for a particular purpose.

The top of the water surface in the saturated part of an aquifer.

Water that is used for a specific purpose, such as for domestic use, irrigation, or industrial processing. Water use pertains to human's interaction with and influence on the hydrologic cycle, and includes elements, such as water withdrawal from surface- and ground-water sources, water delivery to homes and businesses, consumptive use of water, water released from wastewater-treatment plants, water returned to the environment, and instream uses, such as using water to produce hydroelectric power.

An artificial excavation put down by any method for the purposes of withdrawing water from the underground aquifers. A bored, drilled, or driven shaft, or a dug hole whose depth is greater than the largest surface dimension and whose purpose is to reach underground water supplies or oil, or to store or bury fluids below ground.

pH is a measure of the acidity or alkalinity of an aqueous solution and is a good indicator of whether water is hard or soft. Pure water is said to be at a pH of 7, pH lower than 7 is said to be acidic and greater than 7 is considered alkaline. The measure of pH and alkalinity is needed to determine the corrosiveness of water.

A metallic chemical element that is an essential mineral to human health as well as for its use of galvanization. Galvanization is the process of coating other metals with iron or steel. Zinc supports your healthy immune system and is essential for wound healing. Zinc deficiencies can cause health issues such as growth retardation, hair loss, delayed sexual maturation, and many more. Zinc may leach from galvanized water pipes and into drinking water systems which may pose health threats.

A volatile organic compound (VOC) has a molecular make-up containing carbon and chemical properties that allow it to be present as a gas under typical room temperature. The term VOC applies to a very broad category of chemicals, and they can be found in many forms in the environment, including both human-made and naturally occurring chemical compounds. VOCs are most often referred to in the context of chemicals that have the potential to affect the environment or human health.