This desalination plant in Israel, called Sorek, is currently the world’s largest, producing 625,000 cubic meters of fresh water per day. Boris Liberman, chief technology officer of IDE Technologies, the company that built this and several other huge desalination plants in Israel and California, was among the speakers at MIT’s Low Carbon Desalination Workshop, which explored the potential for reducing the carbon footprint of such facilities. (Photo courtesy IDE Technologies)
Experts Gather at MIT to Prepare Roadmap for “Green” Desalination
Written by AZoCleantech
Considered one of the most significant turnarounds ever accomplished in relation to a natural resource emergency, Israel has overcome a threatening fresh water scarcity within a decade.
Currently, the country has such a large water surplus it exports large quantities to its parched neighboring countries. The turnaround was achieved with the construction of the largest desalination plants in the world. The desalination plants convert the Mediterranean seawater into potable water for both domestic purposes as well as agriculture.
Although this excess water is an important example for countries around the world that are dealing with water shortages, it also has an environmental impact: Desalination plants consume a lot of energy, the production of which would require fossil fuels to be burnt in large power plants.
To solve that issue and prepare a roadmap for future research and demonstrations, some of the world’s leading experts in the technology, regulatory issues involving desalination, and economics recently gathered at MIT.
They talked about a way to remove the salt from seawater or brackish aquifers at all scales, from small, local installations to the large megaprojects as seen in Israel, while reducing or eliminating the related greenhouse gas emissions.
Rising sea levels are threatening agricultural production in coastal regions due to inundation and contamination of groundwater. The development of more salt-tolerant crops is essential. Cassava is an important staple, particularly among poor subsistence farmers. Its tolerance to drought and elevated temperatures make it highly suitable for meeting global food demands in the face of climate change, but its ability to tolerate salt is unknown.
Cassava stores nitrogen in the form of cyanogenic glucosides and can cause cyanide poisoning unless correctly processed. Previous research demonstrated that cyanide levels are higher in droughted plants, possibly as a mechanism for increasing resilience to oxidative stress.
We determined the tolerance of cassava to salt at two different stages of development, and tested the hypothesis that cyanide toxicity would be higher in salt-stressed plants.
Cassava was grown at a range of concentrations of sodium chloride (NaCl) at two growth stages: tuber initiation and tuber expansion. Established plants were able to tolerate 100mM NaCl but in younger plants 40mM was sufficient to retard plant growth severely.
Nutrient analysis showed that plants were only able to exclude sodium at low concentrations. The foliar cyanogenic glucoside concentration in young plants increased under moderate salinity stress but was lower in plants grown at high salt. Importantly, there was no significant change in the cyanogenic glucoside concentration in the tubers.
We propose that the mechanisms for salinity tolerance are age dependent, and that this can be traced to the relative cost of leaves in young and old plants.
Prospects of Saline Agriculture in the Arabian Peninsula (2004)
Posted by Prof. Dr. Willem VAN COTTHEM
Ghent University – Belgium
Having participated in all the meetings of the INCD (1992-1994) and all the meetings of the UNCCD-COP, the CST and the CRIC in 1994-2006, I had an opportunity to collect a lot of interesting books and publications on drought and desertification published in that period.
Researchers have developed a protein that helps plants grow in salty soils. This could help in future growth of more salt-tolerant crops.
“More and more of the world’s crops are facing salt stress with high salt in soils (also known as salinity) affecting 20 percent of the total, and 33 percent of irrigated, agricultural lands worldwide, ” Professor Staffan Persson, study leader from the University of Melbourne, Australia, and formerly at the Max Planck Institute of Molecular Plant Physiology, said in a news release. He noted that unlike humans, plants are stuck and can’t move away from the salty snacks or drink more water.
“By 2050 it is estimated that we need to increase our production of food by 70 percent to feed an additional 2.3 billion people. Salinity is a major limiting factor for this goal as more than 50 percent of the arable land may be salt afflicted by the year 2050,” Persson explained in the release. “It is therefore of great agricultural importance to find genes and mechanisms that can improve plant growth under such conditions. ”
The researchers found that a previously unknown family of proteins supports the cellulose-producing protein complex, called cellulose synthase, under salty conditions. This synthase, or enzyme that starts up a synthesis process, is important for plant cells’ shape and stability. This new family of proteins was named Companions of Cellulose synthase (CC). Their findings were recently published in the journalCell.
US and Middle Eastern mayors agree water know-how swap
by Puneet Kollipara
“The partnership will go beyond technology exchange. Mayors who signed the pact will also work on business and educational capacity building and community exchanges.” – Gidon Bromberg, EcoPeace Middle East’s, Israeli
Middle Eastern mayors could learn about restoring polluted waters
US mayors could benefit from desalinisation technology used in the Middle East
The deal may involve workshops, site visits and community exchanges
Mayors in the United States and the Middle East have agreed to share information and technologies for managing water.
The deal is intended to help both sides access each other’s knowledge and experience in tackling problems relating to limited freshwater resources. The Sister Waters agreement was signed on 24 April in Chicago, United States.
Those backing the agreement hope it will enable mayors from Israel, Jordan and Palestine, along with those from the Great Lakes region in the United States, to address weaknesses in their water management. The partners plan to run workshops and site visits, and to swap experts.
“The agreement will hopefully be the beginning of knowledge exchange and technology transfer,” says Rachel Havrelock, head of the Freshwater Lab project at the University of Illinois at Chicago, and organiser of the event where the deal was signed.
Making the Case for Reusing Saline Water and Restoring Salt-affected Agricultural Lands
For centuries, irrigation has been a huge boon for agricultural productivity. While only 20% of the world’s cropland is currently irrigated, that land produces 40% of all food and fiber (Thenkabail et al. 2010). But the long-term sustainability of irrigated systems, and their ability to provide sustained high productivity, remains a major question, in large part due to salt accumulation in the root zone.
Salinity-related problems are particularly problematic in the arid and semiarid areas where irrigation primarily takes place. The two biggest challenges for farmers are minimizing the amount of water that needs to be drained from irrigated landscapes; and the proper disposal or reuse of the salt-laden drainage water. The global annual cost of salt-induced land degradation in irrigated areas (in the form of crop production losses) is estimated to be around US$ 27.3 billion.
While drainage water is often viewed as a problem, it actually offers a number of opportunities. A new report from the CGIAR Research Program on Water, Land and Ecosystems (WLE) proposes a paradigm shift in the way farmers, governments and donors view saline water and salt-affected soils; rather than disposing of saline water, recycle and reuse it until it becomes unusable for any economic activity, and instead of ceasing to cultivate salt-affected soils, restore them. The report suggests that such changes would result in higher levels of production and a significant contribution to food, feed and renewable energy production without requiring any expansion of current agricultural lands.
In class this week we looked at the causes, impacts, and possible solutions to desertification issues around the world. I decided to look more closely at desertification in Egypt, a country which I’ve focused on in a couple of my past blog posts. In Egypt you can find the perfect recipe for desertification–an arid environment with several additional stressing factors such as salinization, over-cultivation, deforestation, and water scarcity.
According to the UN, 6 million hectares of arable land dissapear every year because of desertification, a loss equivalent to an estimated 42 billion dollars. In Egypt, a mere 3% of the country’s surface area is fit for agriculture. Drought, higher levels of salt in the aquifer and the soil, bad farmland drainage and construction on farmlands make up 30% of the total desertification.Duration: 01:43
Source: Agricultural Water Management 162: 243-250
Mismanagement of irrigation water and the ensuing secondary salinization are threatening the sustainability of irrigated agriculture especially in many dryland regions. The permanent raised-bed/furrow system, a water-wise conservation agriculture-based practice, is gaining importance for row- and high value-crops in irrigated agriculture. However, because of additional surface exposure and elevation, raised beds may be more prone to salt accumulation especially under shallow water table conditions. A field study was carried out in 2008 and 2009 in the Khorezm region, Central Asia, to investigate the effect of three furrow irrigation methods on salt dynamics of the soil and the performance of the cotton crop on the raised bed-furrow system. The irrigation methods compared included (i) Conventional furrow irrigation wherein every furrow was irrigated (EFI) at each irrigation event; (ii) Alternate skip furrow irrigation (ASFI where one of two neighbouring furrows were alternately irrigated during consecutive irrigations events; and (iii) Permanent skip furrow irrigation (PSFI) during which irrigation was permanently skipped in one of the two neighbouring furrows during all irrigation events. For salinity management with PSFI a managed salt accumulation and effective leaching approach was pursued.
Ever since 1959/60 with ‘World Refugee Year’ we’ve seen all manner of‘International Years of’ (IYO). These global ‘observances’ are endorsed by the United Nations, an international organisation established after the Second World War and whose noble and worthy objectives include maintaining international peace and security, promoting human rights, fostering social and economic development, protecting the environment, and providing humanitarian aid in cases of famine, natural disaster, and armed conflict. Developing the notion that global problems require global solutions and action – and few issues are more pressing and global than food security – 2015 is the IYO (or on…) Soils (or IYS at it is officially abbreviated).
Background As important components in saline agriculture, halophytes can help to provide food for a growing world population. In addition to being potential crops in their own right, halophytes are also potential sources of salt-resistance genes that might help plant breeders and molecular biologists increase the salt tolerance of conventional crop plants. One especially promising halophyte is Suaeda salsa, a euhalophytic herb that occurs both on inland saline soils and in the intertidal zone.
The species produces dimorphic seeds: black seeds are sensitive to salinity and remain dormant in light under high salt concentrations, while brown seeds can germinate under high salinity (e.g. 600 mM NaCl) regardless of light. Consequently, the species is useful for studying the mechanisms by which dimorphic seeds are adapted to saline environments. S. salsa has succulent leaves and is highly salt tolerant (e.g. its optimal NaCl concentration for growth is 200 mM). A series of S. salsa genes related to salt tolerance have been cloned and their functions tested: these includeSsNHX1, SsHKT1, SsAPX, SsCAT1, SsP5CS and SsBADH. The species is economically important because its fresh branches have high value as a vegetable, and its seed oil is edible and rich in unsaturated fatty acids. Because it can remove salts and heavy metals from saline soils, S. salsacan also be used in the restoration of salinized or contaminated saline land.
Scope Because of its economic and ecological value in saline agriculture,S. salsa is one of the most important halophytes in China. In this review, the value of S. salsa as a source of food, medicine and forage is discussed. Its uses in the restoration of salinized or contaminated land and as a source of salt-resistance genes are also considered.
Background Freshwater comprises about a mere 2·5 % of total global water, of which approximately two-thirds is locked into glaciers at the polar ice caps and on mountains. In conjunction with this, in many instances irrigation with freshwater causes an increase in soil salinity due to overirrigation of agricultural land, inefficient water use and poor drainage of unsuitable soils. The problem of salinity was recognized a long time ago and, due to the importance of irrigated agriculture, numerous efforts have been devoted towards improving crop species for better utilization of saline soils and water. Irrigating plants with saline water is a challenge for practitioners and researchers throughout the world.
Scope Recruiting wild halophytes with economic potential was suggested several decades ago as a way to reduce the damage caused by salinization of soil and water. A range of cultivation systems for the utilization of halophytes have been developed, for the production of biofuel, purification of saline effluent in constructed wetlands, landscaping, cultivation of gourmet vegetables, and more. This review critically analyses past and present halophyte-based production systems in the context of genetics, physiology, agrotechnical issues and product value. There are still difficulties that need to be overcome, such as direct germination in saline conditions or genotype selection. However, more and more research is being directed not only towards determining salt tolerance of halophytes, but also to the improvement of agricultural traits for long-term progress.
How can we take advantage of halophyte properties to cope with heavy metal toxicity in salt-affected areas?
A halophyte is a plant that grows in waters of high salinity, coming into contact with saline water through its roots or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs, and seashores. (Wikipedia)
Background Many areas throughout the world are simultaneously contaminated by high concentrations of soluble salts and by high concentrations of heavy metals that constitute a serious threat to human health. The use of plants to extract or stabilize pollutants is an interesting alternative to classical expensive decontamination procedures. However, suitable plant species still need to be identified for reclamation of substrates presenting a high electrical conductivity.
Scope Halophytic plant species are able to cope with several abiotic constraints occurring simultaneously in their natural environment. This review considers their putative interest for remediation of polluted soil in relation to their ability to sequester absorbed toxic ions in trichomes or vacuoles, to perform efficient osmotic adjustment and to limit the deleterious impact of oxidative stress. These physiological adaptations are considered in relation to the impact of salt on heavy metal bioavailabilty in two types of ecosystem: (1) salt marshes and mangroves, and (2) mine tailings in semi-arid areas.
Conclusions Numerous halophytes exhibit a high level of heavy metal accumulation and external NaCl may directly influence heavy metal speciation and absorption rate. Maintenance of biomass production and plant water status makes some halophytes promising candidates for further management of heavy-metal-polluted areas in both saline and non-saline environments.