Desalination
Both the Classic of Mountains and Water Seas in the Period of the Warring States and the Theory of the Same Year in the Eastern Han Dynasty mentioned that people found that the bamboo mats used for steaming rice would form a thin outer layer after long use.[12] A good example of this experimentation comes from Leonardo da Vinci (Florence, 1452), who realized that distilled water could be made cheaply in large quantities by adapting a still to a cookstove.[14][15] It is believed that a garrison of 700 Spanish soldiers was besieged by the Turkish army and that, during the siege, the captain in charge fabricated a still capable of producing 40 barrels of fresh water per day, though details of the device have not been reported.Sir Richard Hawkins (1562–1622), who made extensive travels in the South Seas, reported that he had been able to supply his men with fresh water by means of shipboard distillation.[16] Additionally, during the early 1600s, several prominent figures of the era such as Francis Bacon and Walter Raleigh published reports on desalination.[21] In the United States, Thomas Jefferson catalogued heat-based methods going back to the 1500s, and formulated practical advice that was publicized to all U.S. ships on the reverse side of sailing clearance permits.[14] Knowledge of the thermodynamics of steam processes[24] and the need for a pure water source for its use in boilers[25] generated a positive effect regarding distilling systems.Additionally, the spread of European colonialism induced a need for freshwater in remote parts of the world, thus creating the appropriate climate for water desalination.[14] In 1852, Alphonse René le Mire de Normandy was issued a British patent for a vertical tube seawater distilling unit that, thanks to its simplicity of design and ease of construction, gained popularity for shipboard use.The Department of the Interior allocated resources including research grants, expert personnel, patent data, and land for experiments to further advancements.[36] Dr. Sidney Loeb, in conjunction with staff at UCLA, designed a large pilot plant to gather data on RO, but was successful enough to provide freshwater to the residents of Coalinga.[46] While noting costs are falling, and generally positive about the technology for affluent areas in proximity to oceans, a 2005 study argued, "Desalinated water may be a solution for some water-stress regions, but not for places that are poor, deep in the interior of a continent, or at high elevation.[64] A recent study has found that the water permeability is primarily governed by the internal nanoscale mass distribution of the polyamide active layer.[68] The reverse osmosis process receives its pressurized seawater feed in non-sunlight hours by gravity, resulting in sustainable drinking water production without the need for fossil fuels, an electricity grid or batteries.[74] Preliminary estimates suggest that the cost of such carbon removal can be paid for in large part if not entirely from the sale of the desalinated water produced as a byproduct.Wave-powered desalination plants began operating by CETO on Garden Island in Western Australia in 2013[80] and in Perth in 2015 [81], and Oneka has installations in Chile, Florida, California, and the Caribbean.After multiple passes through the channel, the researchers were able to achieve a NaCl concentration drop of 25000 ppm with a recovery rate of 10% of the original water volume.[103][104][105] Factors that determine the costs for desalination include capacity and type of facility, location, feed water, labor, energy, financing, and concentrate disposal.[107] Since 1975, desalination technology has seen significant advancements, decreasing the average cost of producing one cubic meter of freshwater from seawater from $1.10 in 2000 to approximately $0.50 today.According to EPA, water intake structures cause adverse environmental impact by sucking fish and shellfish or their eggs into an industrial system.[119] Desalination processes produce large quantities of brine, possibly at above ambient temperature, and contain residues of pretreatment and cleaning chemicals, their reaction byproducts and heavy metals due to corrosion (especially in thermal-based plants).[134] They found a high burden of iodine deficiency in the general population of Israel: 62% of school-age children and 85% of pregnant women fall below the WHO's adequacy range.[135] They also pointed out the national reliance on iodine-depleted desalinated water, the absence of a universal salt iodization program and reports of increased use of thyroid medication in Israel as a possible reasons that the population's iodine intake is low.[140][143][144] In October 2009, Saltworks Technologies announced a process that uses solar or other thermal heat to drive an ionic current that removes all sodium and chlorine ions from the water using ion-exchange membranes.[146] Designed for use by non-experts in remote areas or natural disasters, as well as on military operations, the prototype is the size of a suitcase, measuring 42 × 33.5 × 19 cm3 and weighing 9.25 kg.The consequence of the compression and swelling in open and closed system conditions mimics the reverse Carnot Cycle of refrigerator machine.In this approach, a solar thermal collector measuring two square metres can distill from 40 to 60 litres per day from any local water source – five times more than conventional stills.The compressor centrifuges the pure water vapor after it is drawn through a demister (removing residual impurities) causing it to compress against tubes in the collection chamber.[192] One of the world's largest desalination hubs is the Jebel Ali Power Generation and Water Production Complex in the United Arab Emirates.It is a site featuring multiple plants using different desalination technologies and is capable of producing 2.2 million cubic meters of water per day.
A – steam in B – seawater in C – potable water out
D – brine out (waste) E – condensate out F – heat exchange G – condensation collection (desalinated water)
H – brine heater
The pressure vessel acts as a countercurrent heat exchanger . A vacuum pump lowers the pressure in the vessel to facilitate the evaporation of the heated seawater ( brine ) which enters the vessel from the right side (darker shades indicate lower temperature). The steam condenses on the pipes on top of the vessel in which the fresh sea water moves from the left to the right.
saline watersoil desalinationsea watersubmarinesfresh waterwastewaterwater resourcessurface watergroundwaterwater recyclingwater conservationdistillationreverse osmosiswater sectorAristotleMeteorologyPeriod of the Warring StatesEastern Han Dynastyadsorptionion exchangeMiddle AgesLeonardo da VinciTunisiaIndustrial RevolutionRichard HawkinsSouth SeasFrancis BaconWalter RaleighWilliam WalcotProtectorThomas Jeffersonsteam engineage of steamEuropean colonialismmultiple-effect evaporatorsKey WestDry TortugasSuakinUnited States Department of the InteriorFreeport, TexasDow Chemical CompanyDuPontbrackish waterDr. Sidney LoebScience History Institutemultistage flash desalinatorcondensatepressure vesselcountercurrent heat exchangervacuum pumpUnited Arab EmiratesSaudi ArabiaIsraelRas Al-Khair Power and Desalination PlantPersian GulfMexico CityRiyadhHarareBangkokZaragozaPhoenixTripoliJubailSea of GalileeDebbie CookMulti-stage flash distillationMultiple-effect distillationVapor-compressionMembrane processesElectrodialysis reversalNanofiltrationMembrane distillationForward osmosisFreezing desalinationGeothermal desalinationSolar desalinationSolar humidificationMultiple-effect humidificationSeawater greenhouseMethane hydrateWave-powered desalinationmultistage flash distillationcondensationseawaterSolar distillationsolar irradiationIBTS Greenhousedesert greeningvacuum distillationvapor pressureflash evaporationsVapor-compression evaporationelectrospinningsilica aerogelReverse osmosis plantdissolved organic carboncolloidsbiofoulingscalingpolyacrylamidephosphonatespolyphosphatesbiocidesmarine habitatssolar-powered desalination unitsAlexander ZarchinElectrodialysiscarbonic acidcarbon removalMicrobial desalination cellelectrochemicalin situsupercapacitorwave powerGarden Islandthermophoresiswater suppliesenergy consumptionMulti-stageFlash"MSF"Multi-EffectDistillation"MED"Mechanical VaporCompression"MVC"ReverseOsmosis"RO"Cogenerationfossil fuelsnuclear powerShevchenko BN-350