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Evaporation ponds are artificial
pond A pond is an area filled with water, either natural or artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% emergent vegetation helps in distinguishing their ecology from th ...
s with very large surface areas that are designed to efficiently
evaporate Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humid ...
water by
sunlight Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when th ...
and expose water to the ambient temperatures. Evaporation ponds are inexpensive to design making it ideal for multiple purposes such as
wastewater treatment Wastewater treatment is a process used to remove contaminants from wastewater and convert it into an effluent that can be returned to the water cycle. Once returned to the water cycle, the effluent creates an acceptable impact on the environmen ...
processes, storage, and extraction of minerals. Evaporation ponds differ in usage and result in a wide range of
environmental A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...
and
health Health, according to the World Health Organization, is "a state of complete physical, mental and social well-being and not merely the absence of disease and infirmity".World Health Organization. (2006)''Constitution of the World Health Organiza ...
effects.


Uses


Extraction

Salt evaporation pond 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 large of size because it will be easier for sunlight to travel and reach the sea water. Natural sal ...
s produce
salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantiti ...
from
seawater Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appro ...
. Evaporation ponds are used to extract
Lithium Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid e ...
from underground brine solution. The extracted Lithium is then used to make ion batteries. Mines use them to separate
ore Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 April ...
from water. The ore can be sold for use in different industries. Potash evaporation ponds are used to extract
potassium Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosp ...
from the mineral rich solution. The potassium extracted is used for products like
fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
.


Storage

Evaporation ponds are also used to dispose of
brine Brine is a high-concentration solution of salt (NaCl) in water (H2O). In diverse contexts, ''brine'' may refer to the salt solutions ranging from about 3.5% (a typical concentration of seawater, on the lower end of that of solutions used for b ...
from
desalination Desalination is a process that takes away mineral components from saline water. More generally, desalination refers to the removal of salts and minerals from a target substance, as in soil desalination, which is an issue for agriculture. Saltw ...
plants. Evaporation ponds at contaminated sites remove the water from
hazardous waste Hazardous waste is waste that has substantial or potential threats to public health or the environment. Hazardous waste is a type of dangerous goods. They usually have one or more of the following hazardous traits: ignitability, reactivity, c ...
, which reduces its weight and volume and allows it to be more easily transported and stored. Evaporation ponds are used to prevent run off agricultural wastewater contaminants like
pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
s,
fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
s and
salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantiti ...
s from entering bodies of water they would normally flow into.


Design and Operation

Location of the evaporation pond should be considered for optimal results. Evaporation ponds are designed to be effective in areas with high amounts of
solar radiation Solar irradiance is the power per unit area (surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument. Solar irradiance is measured in watts per square metre (W/ ...
,high temperatures, and low
wind Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few hou ...
levels. Evaporation ponds operate best at shallow depths which require a large amount of land usage.A shallow pond covering greater surface area will result in faster rates of evaporation. Evaporation pond liners that range in quality and cost are used to prevent
contamination Contamination is the presence of a constituent, impurity, or some other undesirable element that spoils, corrupts, infects, makes unfit, or makes inferior a material, physical body, natural environment, workplace, etc. Types of contamination ...
. Evaporation pond liners are categorized as
geomembrane A geomembrane is very low permeability synthetic membrane liner or barrier used with any geotechnical engineering related material so as to control fluid (liquid or gas) migration in a human-made project, structure, or system. Geomembranes are m ...
, constructed
bentonite Bentonite () is an absorbent swelling clay consisting mostly of montmorillonite (a type of smectite) which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably greater swelling capacity than Ca-mon ...
clay, or natural
clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay parti ...
. Each pond liner is prone to leakage and requires regular maintenance. The contents of the evaporation pond depend on the use, the evaporation pond will contain
water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
and the desired contents hoping to be extracted. The desired contents range from
waste Waste (or wastes) are unwanted or unusable materials. Waste is any substance discarded after primary use, or is worthless, defective and of no use. A by-product, by contrast is a joint product of relatively minor economic value. A waste produ ...
to
minerals In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ...
. The
sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
will promote
evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...
of water from the pond. The remaining contents are either stored or extracted.


Health impacts

Evaporation ponds, when not maintained, leak contaminated contents into the environment which directly effect human and animal health. The contents within the evaporation pond can be found to contaminate surrounding soil and surrounding water sources. Contaminated water can contain sources of chemicals and hard metals like
selenium Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium ...
which in accumulation can be
toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...
when ingested by humans or animals. Employees working directly with the evaporation ponds may experience acute health conditions like dry skin and
irritation Irritation, in biology and physiology, is a state of inflammation or painful reaction to allergy or cell-lining damage. A stimulus or agent which induces the state of irritation is an irritant. Irritants are typically thought of as chemical age ...
from close contact of contents within the pond.


Environmental impacts

Evaporation ponds pose a threat to
environmental sustainability Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livin ...
because resources like water, land, and minerals are rapidly used at large scales. These resources are limited in nature. An increasing demand for extracted products and treated wastewater will result in evaporation ponds expanding and related issues worsening until the depletion of these resources. Evaporation ponds are found to increase
green house gas A greenhouse gas (GHG or GhG) is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor (), carbon dioxide (), methane ...
emissions and therefore contribute to environmental issues like warming of the planet and
ocean acidification Ocean acidification is the reduction in the pH value of the Earth’s ocean. Between 1751 and 2021, the average pH value of the ocean surface has decreased from approximately 8.25 to 8.14. The root cause of ocean acidification is carbon dioxide ...
. As the pond evaporates, it carries with it volatile pollutants into the air.


Technology

Advancing technology has made evaporation pond design and implementation more effective. With new resources such as fabric evaporations for salt-tolerant plants, the ponds' costs and environmental impacts can be mediated.


See also

*
Seawater greenhouse A seawater greenhouse is a greenhouse structure that enables the growth of crops and the production of fresh water in arid regions which constitute about one third of the earth's land area. This in response to the global water scarcity and peak ...


References


California Department of Water Resources - Evaporation Ponds
* ttp://www.ars.usda.gov/is/pr/2005/050912.htm USDA - Turning Evaporation Ponds into Arable Landbr>World Bank - AgWater Sourcebook
* * * Ponds Resource extraction Waste treatment technology {{water-stub