Glossary of Terms - H
Also called native salt or fossil salt.
This method of water analysis provides a common basis for comparison of different salts and compounds.
See Also: Calcite Calcium Carbonate Calcite Carbonate Hardness Bicarbonate Hardness Hardness Plastic Pipe Calcium Carbonate Total Hardness (TH) Soda Ash Calcium Carbonate
One purpose of the header is to collect the processed product water, but the header may also be used to distribute backwash water and regenerants across the bottom of the bed area.
Health contaminants in water are regulated as part of the National Primary Drinking Water Regulations enforced by the U.S. Environmental Protection Agency and most states.
See Also: Aesthetic Contaminants Drinking Water Drinking Water Standards Potable (Drinking) Water Safe Drinking Water Act (SDWA) Safe Water Club Soda Community Water System Zone of Saturation Bottled Artesian Water Bottled Distilled Water Bottled Fluoridated Water Bottled Mineral Water Bottled Natural Water Lime Soap Bottled Spring Water Brackish Water Brine Internal Water Treatment Ion Exchange Aesthetic Contaminants Drainage Basin Drinking Water Drinking Water Standards Municipal Water Permutit Process Phosphate Potable (Drinking) Water Etching External Water Treatment United States Pharmacopeia (USP) Water Softening WFI Sulfur (S) Safe Drinking Water Act (SDWA) Safe Water Sewage Silica Sodium Carbonate Softened Water Soft Water Aesthetic Contaminants Potable (Drinking) Water Safe Drinking Water Act (SDWA) Safe Water
This device might be a metal contact, or a thermocouple which generates a minute electrical current proportional to the difference in heat, or a variable resistor whose value changes in response to changes in temperature.
Also called a temperature sensor.
They can damage living things at low concentrations and tend to accumulate in the food chain.
One hectare is equal to 10,000 square meters and 2.4711 acres.
This condition is usually due to the configuration of the vessel or the lack of a good underdrain distribution system.
Heme is found in red blood cells (hemoglobin). It is also found outside the body in the nonprotein portions of some organic molecules called hemoproteins. In water quality treatment, it may be referred to as heme iron, which is organically-bound iron that can cause water to have a pinkish cast to it.
See Also: Iron (Fe) Dissolved Organic Carbon Tannin Total Organic Carbon (TOC) Crenothrix Polyspora Gallionella Ferruginea Organic Iron Iron (Fe) Tannin
See Also: Ion Exchange Membrane Dialysis Electrodialysis
Hemolysis may be caused by the presence of chloramines in dialysis water.
Yellow jaundice is one symptom of hepatitis.
See Also: Organic Aromatic Organic Aliphatic
Obtaining food or nourishment from other organisms.
Heterotrophic organisms or heterotrophs are consumers such as man or decomposers such as bacteria that obtain their nourishment and energy from the organic molecules manufactured by the autotrophic organisms (the producers). All animals, for example, are consumers and heterotrophs that depend on complex organic molecules produced by autotrophs for their food and energy.
See Also: Autotrophic
Colony-forming units (CFU) are counted after spreading an aliquot portion of a sample over a membrane or pour plate and incubating in an amiable growth medium (agar) and at an amiable temperature.
(These generally are not considered to be disease-causing bacteria.)
See Also: Soda Ash Sodium Hexametaphosphate
Among the varied HPLC techniques are:
Reversed phase chromatography, which uses a polar liquid phase for elution of a column containing a nonpolar phase. This technique is used, for example, to analyze the polynuclear aromatic hydrocarbon category (pyrenes, naphthalenes, etc.) of synthetic organic compounds; Ion exchange chromatography, which makes it possible to separate large numbers of cations and anions; Exclusion chromatography, which separates, on a porous gel, compounds according to their size and makes it possible to determine their apparent molecular weights and to separate fractions of different molecular weights for further analyses.
See Also: Chromatography Liquid Chromatography Gas Chromatograph (GC) Gas Chromatography (GC) Mass Spectrometry (MS) Chromatography Liquid Chromatography Chromatography Liquid Chromatography Gas Chromatograph (GC) Gas Chromatography (GC) Mass Spectrometry (MS)
High salting is generally recommended for high total hardness water and water containing high concentrations of dissolved heavy metals.
Homogenized milk is homogeneous because the fat globules have been broken into smaller colloid-sized particles that remain distributed throughout the liquid milk. In nonhomogenized milk, the fat globules rise to the top of the container as cream.
A location in a water line where a hose is connected.
See Also: Lime Softening Hot-Lime Softening Hot Process Softening Hot-Lime Softening Lime (CaO) Lime Softening Burnt Lime (CaO) Ion Exchange Hydrated Lime Hot-Lime Softening Hot Process Softening Municipal Softening Rated Capacity Water Softening Soda Ash Rated Capacity Lime Softening Hot Process Softening Municipal Softening Soda Ash Lime Softening Detergent Municipal Softening Water Softening Soda Ash Sodium Carbonate Lime (CaO) Lime Softening Burnt Lime (CaO) Ion Exchange Hydrated Lime Hot-Lime Softening Hot Process Softening Municipal Softening Rated Capacity Water Softening Soda Ash Rated Capacity
Hot process softening can remove carbon dioxide, silica, and precipitated magnesium and is used mainly for boiler feedwater preparation and sulfur mining.
See Also: Lime Softening Hot-Lime Softening Hot Lime-Soda Softening Lime (CaO) Lime Softening Burnt Lime (CaO) Hydrated Lime Hot-Lime Softening Hot Lime-Soda Softening Municipal Softening Quicklime Water Softening Salinometer Slake Soap Soda Ash Soap Curd Lime (CaO) Lime Softening Burnt Lime (CaO) Ion Exchange Hydrated Lime Hot-Lime Softening Hot Lime-Soda Softening Municipal Softening Rated Capacity Water Softening Soda Ash Rated Capacity Lime Softening Hot-Lime Softening Hot Lime-Soda Softening Lime (CaO) Lime Softening Burnt Lime (CaO) Ion Exchange Hydrated Lime Hot-Lime Softening Hot Lime-Soda Softening Municipal Softening Rated Capacity Water Softening Soda Ash Rated Capacity Lime Softening Hot-Lime Softening Hot Lime-Soda Softening Lime Softening Hot Lime-Soda Softening Municipal Softening Soda Ash Lime (CaO) Lime Softening Burnt Lime (CaO) Ion Exchange Hydrated Lime Hot-Lime Softening Hot Lime-Soda Softening Municipal Softening Rated Capacity Water Softening Soda Ash Rated Capacity
See Also: Lime Softening Hot Lime-Soda Softening Hot Process Softening Hot Lime-Soda Softening Lime (CaO) Lime Softening Burnt Lime (CaO) Ion Exchange Hydrated Lime Hot Lime-Soda Softening Hot Process Softening Municipal Softening Rated Capacity Water Softening Soda Ash Rated Capacity Lime (CaO) Lime Softening Burnt Lime (CaO) Hydrated Lime Hot Lime-Soda Softening Hot Process Softening Municipal Softening Quicklime Water Softening Salinometer Slake Soap Soda Ash Soap Curd Lime (CaO) Lime Softening Burnt Lime (CaO) Ion Exchange Hydrated Lime Hot Lime-Soda Softening Hot Process Softening Municipal Softening Rated Capacity Water Softening Soda Ash Rated Capacity
The evaluation could concern past exposures, current exposures, or anticipated exposures.
See Also: Chelation Chelating Agent Organic Iron Trihalomethanes (THMs) Humic Substances Humin Fulvic Acid Tannin Chelation Chelating Agent Organic Iron Trihalomethanes (THMs) Humin Fulvic Acid Tannin
Humic substances are commonly classified on the basis of solubility.
If a material containing humic substances or humus is extracted with a strong base and the resulting solution is then acidified, the products are a) a nonextractable plant residue called humin, b) a material called humic acid that precipitates from the acidified (pH < 2) solution, and c) an organic material called fulvic acid that remains dissolved in the acidified solution.
The high molecular weight and polyelectrolytic humic substance macromolecules range from a molecular weight of a few hundred for fulvic acid to tens of thousands for the humic acid and humin fractions.
Humic substances form suspected-carcinogenic trihalomethanes (THMs, such as chloroform, dibromochloromethane, bromodichloromethane, and bromoform) by reaction with chlorine. Humic substances are excellent chelating agents that bind with and hold metal ions in water, and they also effectively exchange cations with water.
See Also: Chelation Chelating Agent Organic Iron Chelation Chelating Agent Organic Iron Free Acid Form Weak Acid Cation Exchangers Total Acidity Strong Acid Cation Exchanger Chelation Chelating Agent Organic Iron Trihalomethanes (THMs) Humic Acid Humin Fulvic Acid Tannin Chelation Chelating Agent Organic Iron Free Acid Form Weak Acid Cation Exchangers Total Acidity Strong Acid Cation Exchanger Fulvic Acid
Humins can effectively exchange cations with water and may accumulate quantities of metals. Lignite coal, for example, is largely a humin and humic-acid material, which, through ion exchange, tends to remove some metal ions from water.
See Also: Chelation Chelating Agent Organic Iron Trihalomethanes (THMs) Humic Acid Humic Substances Fulvic Acid Tannin Chelation Chelating Agent Organic Iron Trihalomethanes (THMs) Humic Acid Fulvic Acid Tannin
A strong alkali chemical, calcium hydroxide, obtained by treating (slaking) lime with water in a heat-producing reaction until the calcium oxide has been converted to calcium hydroxide.
Hydrated lime is used in lime softening water treatment.
Also called calcium hydrate; calcium hydroxide; caustic lime; slaked lime.
See Also: Lime (CaO) Lime Softening Burnt Lime (CaO) Hot-Lime Softening Hot Lime-Soda Softening Hot Process Softening Municipal Softening Quicklime Water Softening Salinometer Slake Soap Soda Ash Soap Curd Lime (CaO) Lime Softening Burnt Lime (CaO) Hot-Lime Softening Hot Lime-Soda Softening Hot Process Softening Municipal Softening Quicklime Water Softening Salinometer Slake Soap Soda Ash Soap Curd Lime (CaO) Lime Softening Burnt Lime (CaO) Ion Exchange Hot-Lime Softening Hot Lime-Soda Softening Hot Process Softening Municipal Softening Rated Capacity Water Softening Soda Ash Rated Capacity Lime (CaO) Burnt Lime (CaO)
As the result of classification, the smallest particles tend to rise to the top of the bed while the largest tend to sink to the bottom because of weight or surface area ratio.
See Also: Stratified Bed Thermal Stratification Stratification
See Also: Energy Grade Line (EGL) United States Pharmacopeia (USP) WFI Slope Conventional Filtration Turnover Alkylaryl Sulfonate Alkylbenzene Sulfonate (ABS) Hypolimnion Direct Filtration Energy Grade Line (EGL) Epilimnion
This is the slope of the water surface in an open channel, the slope of the water surface of the groundwater table, or the slope of the water pressure for pipes under pressure.
Hydrocarbons often occur in petroleum products, natural gas, and coals.
HCl may be used as a regenerant for cation resin deionization systems operated in the hydrogen (H+) cycle.
Hydrogen bonds occur in polar compounds such as water by the attraction of a hydrogen atom of one molecule to two unshared electrons of another molecule.
Hydrogen bonds are less than one-tenth as strong as covalent bonds where electrons are actually shared by a pair of atoms, but they significantly affect properties such as the melting point, boiling point, and crystalline structure of substances.
A strong disinfectant and oxidizing agent used mostly in dilute water-based solutions.
Hydrogen peroxide can be formed in water with a 1948-angstrom mercury-vapor ultraviolet lamp.
Hydrogen peroxide may be used in advanced oxidation processes in combination with ozone to encourage the formation of highly reactive hydroxyl radicals; this process is then called the Peroxone process.
Also called peroxide.
A corrosive and flammable gas often found dissolved in well water and often accompanied by iron and low pH values.
Hydrogen sulfide develops from decaying organic matter, from sulfate-reducing bacteria, and from petroleum refining. H2S formation can be catalyzed by a magnesium anode rod in a hot water heater. A very disagreeable "rotten egg" odor is evidence of the presence of hydrogen sulfide.
See Also: Blowdown
An example is the chemical reaction of salt with water which then forms an acid and a base: (NaCl + H2O hydrolyzes to HCl + NaOH).
Hydrometers commonly consist of a thin glass or metal tube graduated to indicate either specific gravities or percentages of solution constituents and weighted so that they float upright.
Example: Cotton is a hydrophilic fiber. The opposite of hydrophobic.
Example: Nylon is a hydrophobic fiber. The opposite of hydrophilic.
See Also: Base Alkali Alkalinity Alkalinity Tests Detergent Methyl Orange Methyl Orange Alkalinity Phenolphthalein Phosphate Soap
Sodium chloride (NaCl) is also a hygroscopic substance.
An early term for reverse osmosis technology.
See Also: Turnover Thermocline Turnover Epilimnion