Salt evaporation pond

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Salt evaporation pond in Manaure, La Guajira, Colombia Salt evaporation pond in Manaure.jpg
Salt evaporation pond in Manaure, La Guajira, Colombia

A salt evaporation pond is a shallow artificial salt pan designed to extract salts from sea water or other brines. The salt pans are shallow and expansive, allowing sunlight to penetrate and reach the seawater. Natural salt pans are formed through geologic processes, where evaporating water leaves behind salt deposits. Some salt evaporation ponds are only slightly modified from their natural version, such as the ponds on Great Inagua in the Bahamas, or the ponds in Jasiira, a few kilometres south of Mogadishu, where seawater is trapped and left to evaporate in the sun.

Contents

During the process of salt winning, seawater or brine is fed into artificially created ponds from which water is drawn out by evaporation, allowing the salt to be subsequently harvested. [1] :517 [2]

The ponds also provide a productive resting and feeding ground for many species of waterbirds, which may include endangered species. [3] However, Ghanaian fisheries scientist RoseEmma Mamaa Entsua-Mensah also noted that salt winning can destroy mangrove forests and mudflats, altering the environment and making it unproductive for other development or fish growth. [4] The ponds are commonly separated by levees. Salt evaporation ponds may also be called salterns, salt works or salt pans.

Algae and color

San Francisco Bay salt ponds Salt ponds SF Bay (dro!d).jpg
San Francisco Bay salt ponds

Due to variable algal concentrations, vivid colors (from pale green to bright red) are created in the evaporation ponds. The color indicates the salinity of the ponds. Microorganisms change their hues as the salinity of the pond increases. In low- to mid-salinity ponds, green algae such as Dunaliella salina are predominant, although these algae can also take on an orange hue. Halobacteria, a type of halophilic Archaea (also known as Haloarchaea), are responsible for changing the color of middle to high-salinity ponds to shades of pink, red, and orange. Other bacteria such as Stichococcus also contribute tints.[ citation needed ]

Examples

Notable salt ponds include:

Until World War II, salt was extracted from sea water in a unique way in Egypt near Alexandria. [11] Posts were set out on the salt pans and covered with several feet of sea water. In time the sea water evaporated, leaving the salt behind on the post, where it was easier to harvest.

Production

Salt pans are shallow open, often metal, pans used to evaporate brine. They are usually found close to the source of the salt. For example, pans used in the solar evaporation of salt from sea water are usually found on the coast, while those used to extract salt from solution-mined brine will be found near to the brine shaft. In this case, extra heat is often provided by lighting fires underneath.

See also

Related Research Articles

A halophile is an extremophile that thrives in high salt concentrations. In chemical terms, halophile refers to a Lewis acidic species that has some ability to extract halides from other chemical species.

<span class="mw-page-title-main">Great Salt Lake</span> Salt lake in Utah, United States

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<span class="mw-page-title-main">Brine</span> Concentrated solution of salt in water

Brine is water with a high-concentration solution of salt. In diverse contexts, brine may refer to the salt solutions ranging from about 3.5% up to about 26%. Brine forms naturally due to evaporation of ground saline water but it is also generated in the mining of sodium chloride. Brine is used for food processing and cooking, for de-icing of roads and other structures, and in a number of technological processes. It is also a by-product of many industrial processes, such as desalination, so it requires wastewater treatment for proper disposal or further utilization.

<span class="mw-page-title-main">Sea salt</span> Salt produced from the evaporation of seawater

Sea salt is salt that is produced by the evaporation of seawater. It is used as a seasoning in foods, cooking, cosmetics and for preserving food. It is also called bay salt, solar salt, or simply salt. Like mined rock salt, production of sea salt has been dated to prehistoric times.

<span class="mw-page-title-main">Salt pan (geology)</span> Flat expanse of ground covered with salt and other minerals

Natural salt pans or salt flats are flat expanses of ground covered with salt and other minerals, usually shining white under the sun. They are found in deserts and are natural formations.

<span class="mw-page-title-main">Lake Grassmere</span> Lagoon in Marlborough Region, South Island

Lake Grassmere / Kapara Te Hau is a New Zealand waituna-type lagoon in the northeastern South Island, close to Cook Strait. The lake is used for the production of salt.

<span class="mw-page-title-main">History of salt</span> Role in human culture

Salt, also referred to as table salt or by its chemical formula NaCl, is an ionic compound made of sodium and chloride ions. All life depends on its chemical properties to survive. It has been used by humans for thousands of years, from food preservation to seasoning. Salt's ability to preserve food was a founding contributor to the development of civilization. It helped eliminate dependence on seasonal availability of food, and made it possible to transport food over large distances. However, salt was often difficult to obtain, so it was a highly valued trade item, and was considered a form of currency by certain people. Many salt roads, such as the Via Salaria in Italy, had been established by the Bronze Age.

<i>Fleur de sel</i> Type of sea salt, used as a garnish

Fleur de sel or flor de sal is a salt that forms as a thin, delicate crust on the surface of seawater as it evaporates. Fleur de sel has been collected since ancient times, and was traditionally used as a purgative and salve. It is now used as a finishing salt to flavor and garnish food. The origin of the name is uncertain, but is perfectly in line with both meanings of fleur: the surface of something and its best part; the fact the salt crust also might form flower-like patterns of crystals might be of influence.

<span class="mw-page-title-main">Lake Assal (Djibouti)</span> Salt lake below sea level

Lake Assal is a crater lake in central-western Djibouti. It is located at the western end of Gulf of Tadjoura between Arta Region, and Tadjoura Region, touching Dikhil Region, at the top of the Great Rift Valley, some 120 km (75 mi) west of Djibouti city. Lake Assal is a saline lake that lies 155 m (509 ft) below sea level in the Afar Triangle, making it the lowest point on land in Africa and the third-lowest point on Earth after the Sea of Galilee and the Dead Sea. No outflow occurs from the lake, and due to high evaporation, the salinity level of its waters is 10 times that of the sea, making it the fourth most saline body of water in the world, behind Garabogazköl, Lake Retba, and Gaet'ale Pond. The salt in the lake is exploited under four concessions awarded in 2002 at the southeast end of the lake; the major share of production is held by Société d’Exploitation du Lac and Société d’Exploitation du Salt Investment S.A de Djibouti.

<span class="mw-page-title-main">Saltern</span> Area or installation for making salt

A saltern is an area or installation for making salt. Salterns include modern salt-making works (saltworks), as well as hypersaline waters that usually contain high concentrations of halophilic microorganisms, primarily haloarchaea but also other halophiles including algae and bacteria.

<span class="mw-page-title-main">Osmotic power</span> Energy available from the difference in the salt concentration between seawater and river water

Osmotic power, salinity gradient power or blue energy is the energy available from the difference in the salt concentration between seawater and river water. Two practical methods for this are reverse electrodialysis (RED) and pressure retarded osmosis (PRO). Both processes rely on osmosis with membranes. The key waste product is brackish water. This byproduct is the result of natural forces that are being harnessed: the flow of fresh water into seas that are made up of salt water.

<span class="mw-page-title-main">Open-pan salt making</span> Brine derivative

Open-pan salt making is a method of salt production wherein salt is extracted from brine using open pans.

<span class="mw-page-title-main">Evaporation pond</span>

Evaporation ponds are artificial ponds with very large surface areas that are designed to efficiently evaporate water by sunlight and expose water to the ambient temperatures. Evaporation ponds are inexpensive to design making it ideal for multiple purposes such as wastewater treatment processes, storage, and extraction of minerals. Evaporation ponds differ in usage and result in a wide range of environmental and health effects.

<span class="mw-page-title-main">Bittern (salt)</span> Solution from evaporation of seawater or brine

Bittern, or nigari, is the salt solution formed when halite precipitates from seawater or brines. Bitterns contain magnesium, calcium, and potassium ions as well as chloride, sulfate, iodide, and other ions.

A seawater greenhouse is a greenhouse structure that enables the growth of crops and the production of fresh water in arid regions. Arid regions constitute about one third of the Earth's land area. Seawater greenhouse technology aims to mitigate issues such as global water scarcity, peak water and soil becoming salted. The system uses seawater and solar energy, and has a similar structure to the pad-and-fan greenhouse, but with additional evaporators and condensers. The seawater is pumped into the greenhouse to create a cool and humid environment, the optimal conditions for the cultivation of temperate crops. The freshwater is produced in a condensed state created by the solar desalination principle, which removes salt and impurities. Finally, the remaining humidified air is expelled from the greenhouse and used to improve growing conditions for outdoor plants.

<span class="mw-page-title-main">South Bay Salt Works</span> Salt factory in southern San Diego, US

The South Bay Salt Works is a salt factory in Chula Vista, in the South Bay region of San Diego County, California.

Bromine production in the United States of 225,000 tonnes in 2013 made that country the second-largest producer of bromine, after Israel. The US supplied 29 percent of world production. Since 2007, all US bromine has been produced by two companies in southern Arkansas, which extract bromine from brine pumped from the Smackover Formation. At an advertised price of US$3.50 to US$3.90 per kg, the US 2013 US production would have a value of roughly US$800 million.

Brine mining is the extraction of useful materials which are naturally dissolved in brine. The brine may be seawater, other surface water, groundwater, or hyper-saline solutions from several industries. It differs from solution mining or in-situ leaching in that those methods inject water or chemicals to dissolve materials which are in a solid state; in brine mining, the materials are already dissolved.

<span class="mw-page-title-main">San Francisco Bay Salt Ponds</span> Salt evaporation ponds in the San Francisco Bay in California

The San Francisco Bay Salt Ponds are a roughly 16,500-acre (6,700 ha) part of the San Francisco Bay that have been used as salt evaporation ponds since the California Gold Rush era. Most of the ponds were once wetlands in the cities of Redwood City, Newark, and Hayward, and other parts of the bay.

An anchialine system is a landlocked body of water with a subterranean connection to the ocean. Depending on its formation, these systems can exist in one of two primary forms: pools or caves. The primary differentiating characteristics between pools and caves is the availability of light; cave systems are generally aphotic while pools are euphotic. The difference in light availability has a large influence on the biology of a given system. Anchialine systems are a feature of coastal aquifers which are density stratified, with water near the surface being fresh or brackish, and saline water intruding from the coast at depth. Depending on the site, it is sometimes possible to access the deeper saline water directly in the anchialine pool, or sometimes it may be accessible by cave diving.

References

  1. Davies-Vollum, K. Siân; Wes, Matthew (August 2015). "Shoreline Change and Sea Level Rise at the Muni-Pomadze Coastal Wetland (Ramsar Site), Ghana". Journal of Coastal Conservation. 19 (4). Heidelberg, Germany: Springer Science & Business Media: 515–525. doi:10.1007/s11852-015-0403-y. ISSN   1400-0350. OCLC   5889482841 . Retrieved 27 February 2024.
  2. Morrison, Philip (November 1978). "Books: The History of Salt, the Rise of the 'Chip' and How the Indians Lost Faith in Their Game". Scientific American . 239 (5). New York, New York: Scientific American, Inc.: 35–36. ISSN   0036-8733. OCLC   9986402667 . Retrieved 27 February 2024.
  3. Athearn, Nicole D.; Takekawa, John Y.; and Shinn, Joel M. (2009) Avian response to early tidal salt marsh restoration at former commercial salt evaporation ponds in San Francisco Bay, California, USA, Natural Resources and Environmental Issues: Vol. 15, Article 14.
  4. Ashon, Enimil (10 March 2017). "The Woman Who Saw Tomorrow". The Graphic . Accra, Ghana. Archived from the original on 25 February 2024. Retrieved 27 February 2024.
  5. Napa Salt Pond Complex Archived 2011-08-19 at the Wayback Machine , The Bay Institute
  6. Salt ponds, South San Francisco Bay, NASA Earth Observatory
  7. "NASA Helps Reclaim 15,100 Acres Of San Francisco Bay Salt Ponds". Space Daily. Moffett Field. July 14, 2003.
  8. "Cargill Salt - San Francisco Bay". Archived from the original on 2011-08-07. Retrieved 2011-08-09.
  9. "The Salt Works". 19 July 2011.
  10. "Baleni Cultural Camp". African Ivory Route. Transfrontier Parks Destinations. Retrieved 11 September 2019.
  11. Salt, Grown On Sticks Harvested From Sea, Popular Science, March 1933