Saline water
Encyclopedia
Saline water is a general term for water
that contains a significant concentration of dissolved
salt
s (NaCl
). The concentration is usually expressed in parts per million (ppm) of salt.
Water that is saline contains significant amounts (referred to as "concentrations") of dissolved salts. In this case, the concentration is the amount (by weight) of salt in water, as expressed in "parts per million" (ppm). If water has a concentration of 10,000 ppm of dissolved salts, then one percent (10,000 divided by 1,000,000) of the weight of the water comes from dissolved salts.The salinity concentration level used by United States Geological Survey
classifies saline water in three categories. Slightly saline water contains around 1,000 to 3,000 ppm. Moderately saline water contains roughly 3,000 to 10,000 ppm. Highly saline water has around 10,000 to 35,000 ppm of salt. Seawater
has a salinity
of roughly 35,000 ppm, equivalent to 35 g/L.
Some industries make use of saline water, such as mining and thermoelectric-power.
, 14 percent of all water used in 2000 was saline. Almost all saline withdrawals, over 92 percent, were used by the thermoelectric-power industry to cool electricity-generating equipment. About three percent of the nation's saline water was used for mining and other industrial purposes.
Due to their proximity to the Atlantic and Pacific Oceans, states near the coast make the most use of saline water. Almost 40% of all saline water use in 2000 occurred in California
, Florida
, and Maryland
.
The use of saline water, as with freshwater, has been trending downward since a peak in 1968. But, in the period between 1950 and 1968, the use of saline water increased at a much higher rate than freshwater use.
The thermal conductivity
decreases with increasing salinity and increases with increasing temperature;
these graphs and online calculations plot thermal conductivity for varying salinity and temperature: http://twt.mpei.ac.ru/tthb/2/Tab-5-5-13-2-Ther-Cond-Seawater.html
The salt content can be determined with a salinometer
.
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
that contains a significant concentration of dissolved
Solvation
Solvation, also sometimes called dissolution, is the process of attraction and association of molecules of a solvent with molecules or ions of a solute...
salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
s (NaCl
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
). The concentration is usually expressed in parts per million (ppm) of salt.
Water that is saline contains significant amounts (referred to as "concentrations") of dissolved salts. In this case, the concentration is the amount (by weight) of salt in water, as expressed in "parts per million" (ppm). If water has a concentration of 10,000 ppm of dissolved salts, then one percent (10,000 divided by 1,000,000) of the weight of the water comes from dissolved salts.The salinity concentration level used by United States Geological Survey
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
classifies saline water in three categories. Slightly saline water contains around 1,000 to 3,000 ppm. Moderately saline water contains roughly 3,000 to 10,000 ppm. Highly saline water has around 10,000 to 35,000 ppm of salt. Seawater
Seawater
Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...
has a salinity
Salinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
of roughly 35,000 ppm, equivalent to 35 g/L.
Some industries make use of saline water, such as mining and thermoelectric-power.
| Water salinity based on dissolved salts in parts per thousand (‰) | |||
|---|---|---|---|
| Fresh water Fresh Water Fresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve... |
Brackish water Brackish water Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"... |
Saline water | Brine Brine Brine is water, saturated or nearly saturated with salt .Brine is used to preserve vegetables, fruit, fish, and meat, in a process known as brining . Brine is also commonly used to age Halloumi and Feta cheeses, or for pickling foodstuffs, as a means of preserving them... |
| < 0.5 | 0.5 – 30 | 30 – 50 | > 50 |
Use in the United States
In the United StatesUnited States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, 14 percent of all water used in 2000 was saline. Almost all saline withdrawals, over 92 percent, were used by the thermoelectric-power industry to cool electricity-generating equipment. About three percent of the nation's saline water was used for mining and other industrial purposes.
Due to their proximity to the Atlantic and Pacific Oceans, states near the coast make the most use of saline water. Almost 40% of all saline water use in 2000 occurred in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, and Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
.
The use of saline water, as with freshwater, has been trending downward since a peak in 1968. But, in the period between 1950 and 1968, the use of saline water increased at a much higher rate than freshwater use.
Properties
The thermal conductivity of seawater is 0.6 W/mK at 25 degC and a salinity of 35 g/kg.http://web.mit.edu/lienhard/www/Thermophysical_properties_of_seawater-DWT-16-354-2010.pdf.The thermal conductivity
Thermal conductivity
In physics, thermal conductivity, k, is the property of a material's ability to conduct heat. It appears primarily in Fourier's Law for heat conduction....
decreases with increasing salinity and increases with increasing temperature;
these graphs and online calculations plot thermal conductivity for varying salinity and temperature: http://twt.mpei.ac.ru/tthb/2/Tab-5-5-13-2-Ther-Cond-Seawater.html
The salt content can be determined with a salinometer
Salinometer
A salinometer is a device designed to measure the salinity, or dissolved salt content, of a solution.Since the salinity affect both the electrical conductivity and the specific gravity of a solution, a salinometer often consist of an ec meter or hydrometer and some means of converting those...
.