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. [1] Evaporation ponds are inexpensive to design making it ideal for multiple purposes such as wastewater treatment processes, storage, and extraction of minerals. [2] [3] Evaporation ponds differ in usage and result in a wide range of environmental and health effects. [2]
Salt evaporation ponds produce salt from seawater. [4] Evaporation ponds are used to extract Lithium from underground brine solution. The extracted Lithium is then used to make ion batteries. [5] [3] Mines use them to separate ore from water. The ore can be sold for use in different industries. [3] Potash evaporation ponds are used to extract potassium from the mineral rich solution. The potassium extracted is used for products like fertilizer. [6]
Evaporation ponds are also used to dispose of brine from desalination plants. [4] Evaporation ponds at contaminated sites remove the water from hazardous waste, which reduces its weight and volume and allows it to be more easily transported and stored. [3] [4] Evaporation ponds are used to prevent run off agricultural wastewater contaminants like pesticides, fertilizers and salts from entering bodies of water they would normally flow into. [2]
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 ,high temperatures, and low wind levels. Evaporation ponds operate best at shallow depths which require a large amount of land usage. [2] A shallow pond covering greater surface area will result in faster rates of evaporation. [2] Evaporation pond liners that range in quality and cost are used to prevent contamination. Evaporation pond liners are categorized as geomembrane, constructed bentonite clay, or natural clay. [7] Each pond liner is prone to leakage and requires regular maintenance. [2] The contents of the evaporation pond depend on the use, the evaporation pond will contain water and the desired contents hoping to be extracted. The desired contents range from waste to minerals. The sun will promote evaporation of water from the pond. The remaining contents are either stored or extracted. [2]
Evaporation ponds, when not maintained, leak contaminated contents into the environment which directly effect human and animal health. [2] 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 which in accumulation can be toxic when ingested by humans or animals. [2] [8] Employees working directly with the evaporation ponds may experience acute health conditions like dry skin and irritation from close contact of contents within the pond. [2]
Evaporation ponds pose a threat to environmental sustainability 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. [2] Evaporation ponds are found to increase green house gas emissions and therefore contribute to environmental issues like warming of the planet and ocean acidification. As the pond evaporates, it carries with it volatile pollutants into the air. [2]
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. [9]
Lithium carbonate is an inorganic compound, the lithium salt of carbonic acid with the formula Li
2CO
3. This white salt is widely used in processing metal oxides. It is on the World Health Organization's List of Essential Medicines for its efficacy in the treatment of mood disorders such as bipolar disorder.
Brine is a high-concentration solution of salt in water. 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.
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. Saltwater is desalinated to produce water suitable for human consumption or irrigation. The by-product of the desalination process is brine. Desalination is used on many seagoing ships and submarines. Most of the modern interest in desalination is focused on cost-effective provision of fresh water for human use. Along with recycled wastewater, it is one of the few rainfall-independent water resources.
Geothermal desalination refers to the process of using geothermal energy to power the process of converting salt water to fresh water. The process is considered economically efficient, and while overall environmental impact is uncertain, it has potential to be more environmentally friendly compared to conventional desalination options. Geothermal desalination plants have already been successful in various regions, and there is potential for further development to allow the process to be used in an increased number of water scarce regions.
Forward osmosis (FO) is an osmotic process that, like reverse osmosis (RO), uses a semi-permeable membrane to effect separation of water from dissolved solutes. The driving force for this separation is an osmotic pressure gradient, such that a "draw" solution of high concentration, is used to induce a net flow of water through the membrane into the draw solution, thus effectively separating the feed water from its solutes. In contrast, the reverse osmosis process uses hydraulic pressure as the driving force for separation, which serves to counteract the osmotic pressure gradient that would otherwise favor water flux from the permeate to the feed. Hence significantly more energy is required for reverse osmosis compared to forward osmosis.
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 geological processes, where water evaporating, leaving behind salts 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.
Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater may be reused or released to a sanitary sewer or to a surface water in the environment. Some industrial facilities generate wastewater that can be treated in sewage treatment plants. Most industrial processes, such as petroleum refineries, chemical and petrochemical plants have their own specialized facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the regulations regarding disposal of wastewaters into sewers or into rivers, lakes or oceans. This applies to industries that generate wastewater with high concentrations of organic matter, toxic pollutants or nutrients such as ammonia. Some industries install a pre-treatment system to remove some pollutants, and then discharge the partially treated wastewater to the municipal sewer system.
Physical plant, mechanical plant or industrial plant refers to the necessary infrastructure used in operation and maintenance of a given facility. The operation of these facilities, or the department of an organization which does so, is called "plant operations" or facility management. Industrial plant should not be confused with "manufacturing plant" in the sense of "a factory". This is a holistic look at the architecture, design, equipment, and other peripheral systems linked with a plant required to operate or maintain it.
Solar desalination is a desalination technique powered by solar energy. The two common methods are direct (thermal) and indirect (photovoltaic).
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.
Sociedad Química y Minera de Chile (SQM) is a Chilean chemical company and a supplier of plant nutrients, iodine, lithium and industrial chemicals. It is the world’s biggest lithium producer.
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.
Reverse osmosis (RO) is a water purification process that uses a semi-permeable membrane to separate water molecules from other substances. RO applies pressure to overcome osmotic pressure that favors even distributions. RO can remove dissolved or suspended chemical species as well as biological substances, and is used in industrial processes and the production of potable water. RO retains the solute on the pressurized side of the membrane and the purified solvent passes to the other side. It relies on the relative sizes of the various molecules to decide what passes through. "Selective" membranes reject large molecules, while accepting smaller molecules.
Pressure retarded osmosis (PRO) is a technique to separate a solvent from a solution that is more concentrated and also pressurized. A semipermeable membrane allows the solvent to pass to the concentrated solution side by osmosis. The technique can be used to generate power from the salinity gradient energy resulting from the difference in the salt concentration between sea and river water. In PRO, the water potential between fresh water and sea water corresponds to a pressure of 26 bars. This pressure is equivalent to a column of water 270 meters high. However, the optimal working pressure is only half of this, 11 to 15 bar.
Environmental effects of mining can occur at local, regional, and global scales through direct and indirect mining practices. Mining can cause in erosion, sinkholes, loss of biodiversity, or the contamination of soil, groundwater, and surface water by chemicals emitted from mining processes. These processes also affect the atmosphere through carbon emissions which contributes to climate change. Some mining methods may have such significant environmental and public health effects that mining companies in some countries are required to follow strict environmental and rehabilitation codes to ensure that the mined area returns to its original state.
Membrane distillation (MD) is a thermally driven separation process in which separation is driven by phase change. A hydrophobic membrane presents a barrier for the liquid phase, allowing the vapour phase to pass through the membrane's pores. The driving force of the process is a partial vapour pressure difference commonly triggered by a temperature difference.
Zero Liquid Discharge(ZLD) is a water treatment process designed to remove all the liquid waste from a system. The focus of ZLD is to reduce wastewater economically and produce clean water that is suitable for reuse (e.g. irrigation), thereby saving money and being beneficial to the environment. ZLD systems employ advanced wastewater/desalination treatment technologies to purify and recycle virtually all of the wastewater produced.
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.
Petrolithium is lithium derived from petroleum brine, the mineral-rich salt solution that is brought to the surface during oil and gas production and exploration.
Mohamed Thameur Chaibi is a Tunisian professor of Rural Engineering at the National Research Institute for Agricultural Engineering.
