Water is the most precious resource for sustaining life and survival of living world, but we are losing fresh water at an astonishing rate: Climate change is resulting in disappearing of glaciers and severe droughts, groundwater being pumped out faster than natural processes can replace it. Much of the world faces a hotter and drier future under climate change, according to scientists. Rainfall – including the monsoons that fortify agriculture in south Asia – will become more unpredictable. Storm surges could contaminate freshwater reservoirs.
The Overall global water demand is projected to increase by 55 percent on the way to 2050 led by countries like Brazil, Russia, India, Indonesia and China (BRIICS) to satisfy the needs of ever-growing population —a staggering 9.6 billion people by 2050. In countries like China, the largest growth rate in water use will be in the industrial and domestic sectors according to the Water Resources Group. And new fault lines are emerging with energy production. America’s oil and gas rush is putting growing demands on a water supply already under pressure from drought and growing populations.
On September 25, 2015, the global development agenda for the next 15 years was set at the United Nations General Assembly following the adoption of the Sustainable Development Goals (SDGs). Stand-alone and integrated water goal SDG6 has been included, specifically SDG 6.4 aims to “substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity and substantially reduce the number of people suffering from water scarcity.”
Seven powerful start-ups highlighted the latest innovations in water-tech, including real-time analytics, machine learning, AI, biotechnology, water infrastructure financing, wastewater treatment, industrial sludge management and data modelling at World Water-Tech North America in Los Angeles, during October 2019.
Engineering solutions to water shortages—including the transfer of water between rivers—are becoming increasingly common, particularly as urban water demands grow. Under China’s south-to-north diversion project, 9.5 billion cubic meters of water shall be supplied annually to the northern regions, including the cities of Beijing and Tianjin, and provinces of Henan and Hebei.
Technology solutions for Water Security
The optimum use of space technology can help curb the fast-growing water crisis around the globe, especially in countries like Pakistan that has been ranked 26th among the most water-stressed states.
“Not only the space technology provides cost-efficient methods for water management, it also accurately monitors and predicts the long-term trends of depletion of resources,” said Federal Minister for Power Awais Ahmed Khan Leghari on Friday as he spoke on the concluding ceremony of the 4th International Conference on the ‘Use of Space Technology for Water Management’. Elaborating on the technical side, the experts also discussed ways to expand the use of space technology in form of satellite-based remotely sensed data, geographic information system (GIS) and subsequent information products for better management of water resources.
“We need to use water efficiently and it can be carried out through well-defined water property rights, besides reuse of seawater through desalination and building additional water storage facilities,” the minister stated.
Rezatec (UK) applies satellite data, artificial intelligence and data modelling to solve some of the biggest challenges facing the water industry. From predicting where leaks will occur in a water network, to identifying sources of pollution to improve water quality, Rezatec helps its customers around the world to improve their margins, enhance competitive advantage and optimize asset management.
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. 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 sources. Desalination is particularly relevant in dry countries such as Australia, which traditionally have relied on collecting rainfall behind dams for water.
Due to its energy consumption, desalinating sea water is generally more costly than fresh water from surface water or groundwater, water recycling and water conservation. However, these alternatives are not always available and depletion of reserves is a critical problem worldwide.Desalination processes are usually driven by either thermal (in the case of distillation) or electrical (in the case of reverse osmosis) as the primary energy types.
Voltea, the global leader in electro-desalination water treatment technology, was named the Breakthrough Water Technology Company of the Year by Global Water Intelligence (GWI) at this week’s Global Water Awards ceremony in Paris. GWI cited Voltea’s “successful commercialization of its CapDI© technology” as a key factor in earning the award.
“2017 saw Voltea’s capacitive deionisation (CapDI) technology take off as one of the most successful alternatives to reverse osmosis in recent years,” GWI said. “It gained significant market traction in the industrial and commercial sectors, with over 100 systems being shipped. The company also closed a $10 million funding round to further accelerate its growth, and brought the full capacity of its robotic module assembly plant in Dallas online.”
Voltea’s industrial and commercial CapDI© systems run with patented CapDI technology, which monitors incoming water quality in real time, and self-adjusts performance to ensure it delivers consistent, precise water quality. CapDI technology is a simple, two-step process wherein water flows between electrodes. The electrode surfaces are separated from the water by ion-selective membranes that allow positive or negative ions (salts) to pass. The system is tunable, allowing adjustable salt removal and continually adjusts to account for any fluctuations in feed water characteristics.
Israel has built the world’s largest modern seawater desalination plant, the Sorek Plant that provide 20 percent of the water consumed by the country’s households. Built for the Israeli government by Israel Desalination Enterprises, or IDE Technologies, at a cost of around $500 million, it uses a conventional desalination technology called reverse osmosis (RO). At the heart of the Sorek plant are polymer membranes inside tubes. When seawater is passed through the tubes and placed under pressure, fresh water is forced through the membranes, and saltier water is held back
The Sorek plant by incorporating a number of engineering improvements like large diameter pressure tubes, and highly efficient pumps and energy recovery devices has produced a desalination plant with lowest energy consumption. In the future advanced membranes made of atom-thick sheets of carbon, hold the promise of further cutting the energy needs of desalination plants. By 2016, when additional plants will be running, some 50 percent of the country’s water is expected to come from desalination. It has demonstrated that seawater desalination can cost-effectively provide a substantial portion of a nation’s water supply.
The United Arab Emirates, faced with a growing population, have invested in desalination projects and is harvesting rainwater. Australia, Singapore, and several countries in the Persian Gulf are already heavy users of seawater desalination, and California is also starting to embrace the technology
More than 1.8 billion people live in countries where fresh water is scarce. In many arid regions, seawater or salty groundwater is plentiful but costly to desalinate. In addition, many industries pay high disposal costs for wastewater with high salt concentrations that cannot be treated using conventional technologies. Reverse osmosis, the most common desalination technology, requires greater and greater pressure as the salt content of water increases and cannot be used to treat water that is extremely salty, or hypersaline.
Hypersaline water, which can contain 10 times more salt than seawater, is an increasingly important challenge for many industries. Some oil and gas wells produce it in large volumes, for example, and it is a byproduct of many desalination technologies that produce both freshwater and concentrated brine. Increasing water consciousness across all industries is also a driver, said Rice’s Qilin Li, co-corresponding author of a study about Rice’s desalination technology published in Nature Nanotechnology.
“It’s not just the oil industry,” said Li, co-director of the Rice-based Nanotechnology Enabled Water Treatment Center (NEWT). “Industrial processes, in general, produce salty wastewater because the trend is to reuse water. Many industries are trying to have ‘closed loop’ water systems. Each time you recover freshwater, the salt in it becomes more concentrated. Eventually the wastewater becomes hypersaline and you either have to desalinate it or pay to dispose of it.”
Graphene-based sieve for Seawater desalination
Desalination is another strategy, which is especially effective in coastal areas. But the process had been expensive and energy-intensive. Now, Researchers at the University of Manchester in England have developed a graphene-based membrane that filters the salt out of seawater, making it drinkable. This development could provide drinking water to millions of people who live in countries where access to fresh, drinkable water is limited. It’s also a promising discovery for South Africa – the Western Cape in particular – given the drought.
Graphene oxide membranes have already proven their worth in sieving out small nanoparticles, organic molecules and even large salts. But until now, they couldn’t be used to filter out common salts, which require even smaller sieves. Previous work had shown that graphene oxide membranes became slightly swollen when immersed in water, allowing smaller salts to flow through the pores along with water molecules. Now, Dr Nair and colleagues demonstrated that placing walls made of epoxy resin (a substance used in coatings and glues) on either side of the graphene oxide membrane was sufficient to stop the expansion
Breakthrough technology purifies water using using metal-organic frameworks (MOFs) & sunlight
A global research team has been able to transform brackish water and seawater into safe, clean drinking water in less than 30 minutes using metal-organic frameworks (MOFs) and sunlight. Lead author Professor Huanting Wang from the Department of Chemical Engineering at Monash University in Australia, said this work opened up a new direction for designing stimuli-responsive materials for energy-efficient and sustainable desalination and water purification. The World Health Organization suggests good quality drinking water should have a total dissolved solid (TDS) of <600 parts per million (ppm). Researchers were able to achieve a TDS of <500 ppm in just 30 minutes and regenerate the MOF for reuse in four minutes under sunlight.
“Desalination has been used to address escalating water shortages globally. Due to the availability of brackish water and seawater, and because desalination processes are reliable, treated water can be integrated within existing aquatic systems with minimal health risks,” Professor Wang said. “But, thermal desalination processes by evaporation are energy-intensive, and other technologies, such as reverse osmosis, has a number of drawbacks, including high energy consumption and chemical usage in membrane cleaning and dechlorination. “Sunlight is the most abundant and renewable source of energy on Earth. Our development of a new adsorbent-based desalination process through the use of sunlight for regeneration provides an energy-efficient and environmentally-sustainable solution for desalination.”
Metal-organic frameworks are a class of compounds consisting of metal ions that form a crystalline material with the largest surface area of any material known. In fact, MOFs are so porous that they can fit the entire surface of a football field in a teaspoon. The research team created a dedicated MOF called PSP-MIL-53. This was synthesised by introducing poly(spiropyran acrylate) (PSP) into the pores of MIL-53 – a specialised MOF well-known for its breathing effects and transitions upon the adsorption of molecules such as water and carbon dioxide. Researchers demonstrated that PSP-MIL-53 was able to yield 139.5L of fresh water per kilogram of MOF per day, with a low energy consumption. This was from desalinating 2,233 ppm water sourced from a river, lake or aquifer.
Professor Wang said this highlights the durability and sustainability of using this MOF for future clean water solutions. “This study has successfully demonstrated that the photoresponsive MOFs are a promising, energy-efficient, and sustainable adsorbent for desalination,” Professor Wang said. “Our work provides an exciting new route for the design of functional materials for using solar energy to reduce the energy demand and improve the sustainability of water desalination. “These sunlight-responsive MOFs can potentially be further functionalised for low-energy and environmentally-friendly means of extracting minerals for sustainable mining and other related applications.”
Boron nitride coating is key ingredient in hypersaline desalination technology reported by Rice in Nov 2020
Conventional technology to desalinate hypersaline water has high capital costs and requires extensive infrastructure. NEWT, a National Science Foundation (NSF) Engineering Research Center (ERC) headquartered at Rice’s Brown School of Engineering, is using the latest advances in nanotechnology and materials science to create decentralized, fit-for-purpose technologies for treating drinking water and industrial wastewater more efficiently.
One of NEWT’s technologies is an off-grid desalination system that uses solar energy and a process called membrane distillation. When the brine is flowed across one side of a porous membrane, it is heated up at the membrane surface by a photothermal coating that absorbs sunlight and generates heat. When cold freshwater is flowed across the other side of the membrane, the difference in temperature creates a pressure gradient that drives water vapor through the membrane from the hot to the cold side, leaving salts and other nonvolatile contaminants behind.
A large difference in temperature on each side of the membrane is the key to membrane desalination efficiency. In NEWT’s solar-powered version of the technology, light-activated nanoparticles attached to the membrane capture all the necessary energy from the sun, resulting in high energy efficiency. Li is working with a NEWT industrial partner to develop a version of the technology that can be deployed for humanitarian purposes. But unconcentrated solar power alone isn’t sufficient for high-rate desalination of hypersaline brine, she said.
“The energy intensity is limited with ambient solar energy,” said Li, a professor of civil and environmental engineering. “The energy input is only one kilowatt per meter square, and the production rate of water is slow for large-scale systems.” Adding heat to the membrane surface can produce exponential improvements in the volume of freshwater that each square foot of membrane can produce each minute, a measure known as flux. But saltwater is highly corrosive, and it becomes more corrosive when heated. Traditional metallic heating elements get destroyed quickly, and many nonmetallic alternatives fare little better or have insufficient conductivity.
“We were really looking for a material that would be highly electrically conductive and also support large current density without being corroded in this highly salty water,” Li said. The solution came from study co-authors Jun Lou and Pulickel Ajayan in Rice’s Department of Materials Science and NanoEngineering (MSNE). Lou, Ajayan and NEWT postdoctoral researchers and study co-lead authors Kuichang Zuo and Weipeng Wang, and study co-author and graduate student Shuai Jia developed a process for coating a fine stainless steel mesh with a thin film of hexagonal boron nitride (hBN). Boron nitride’s combination of chemical resistance and thermal conductivity has made its ceramic form a prized asset in high-temperature equipment, but hBN, the atom-thick 2-D form of the material, is typically grown on flat surfaces.
“This is the first time this beautiful hBN coating has been grown on an irregular, porous surface,” Li said. “It’s a challenge, because anywhere you have a defect in the hBN coating, you will start to have corrosion.” Jia and Wang used a modified chemical vapor deposition (CVD) technique to grow dozens of layers of hBN on a nontreated, commercially available stainless steel mesh. The technique extended previous Rice research into the growth of 2-D materials on curved surfaces, which was supported by the Center for Atomically Thin Multifunctional Coatings, or ATOMIC. The ATOMIC Center is also hosted by Rice and supported by the NSF’s Industry/University Cooperative Research Program.
The researchers showed that the wire mesh coating, which was only about one 10-millionth of a meter thick, was sufficient to encase the interwoven wires and protect them from the corrosive forces of hypersaline water. The coated wire mesh heating element was attached to a commercially available polyvinylidene difluoride membrane that was rolled into a spiral-wound module, a space-saving form used in many commercial filters. In tests, researchers powered the heating element with voltage at a household frequency of 50 hertz and power densities as high as 50 kilowatts per square meter. At maximum power, the system produced a flux of more than 42 kilograms of water per square meter of membrane per hour—more than 10 times greater than ambient solar membrane distillation technologies—at an energy efficiency much higher than existing membrane distillation technologies.
Li said the team is looking for an industry partner to scale up the CVD coating process and produce a larger prototype for small-scale field tests. “We’re ready to pursue some commercial applications,” she said. “Scaling up from the lab-scale process to a large 2-D CVD sheet will require external support.”
Solar-powered device produces energy and cleans water at the same time
By mounting a water distillation system on the back of a solar cell, engineers have constructed a device that doubles as an energy generator and water purifier. “Our cheap PV-MD approach can be a viable solution to produce drinking water for the impoverished communities in developing countries,” Peng Wang, associate professor at the King Abdullah University of Science and Technology in Saudi Arabia and one of the paper’s authors, tells Inverse.
While the solar cell harvests sunlight for electricity, heat from the solar panel drives evaporation in the water distiller below. That vapor wafts through a porous polystyrene membrane that filters out salt and other contaminants, allowing clean water to condense on the other side. “It doesn’t affect the electricity production by the [solar cell]. And at the same time, it gives you bonus freshwater,” says study coauthor Peng Wang, an engineer at King Abdullah University of Science and Technology in Thuwal, Saudi Arabia.
Solar farms that install these two-for-one machines could help meet the increasing global demand for freshwater while cranking out electricity, researchers report online July 9 in Nature Communications.
In lab experiments under a lamp whose illumination mimics the sun, a prototype device converted about 11 percent of incoming light into electricity. That’s comparable to commercial solar cells, which usually transform some 10 to 20 percent of the sunlight they soak up into usable energy. The researchers tested how well their prototype purified water by feeding saltwater and dirty water laced with heavy metals into the distiller. Based on those experiments, a device about a meter across is estimated to pump out about 1.7 kilograms of clean water per hour.
“It’s really good engineering work,” says George Ni, an engineer who worked on water distillation while a graduate student at MIT, but was not involved in the new study. “The next step is, how are you going to deploy this?” Ni says. “Is it going to be on a roof? If so, how do you get a source of water to it? If it’s going to be [floating] in the ocean, how do you keep it steady” so that it isn’t toppled by waves? Such practical considerations would need to be hammered out for the device to enter real-world use.
New zero energy technology to produce drinking water
Crystal Lagoons, a patented technology developer of giant crystalline lagoons, has developed a new technology to deal with a shortage of potable fresh water, a problem that affects more than a billion people worldwide.
The experimental desalination technology project is a ‘zero energy’ solution that would use wasted energy from Northern Chile’s 12 thermo-electric plants to potentially generate enough potable water for the country’s entire population, said a statement. This wasted energy is the equivalent of eight times the world’s renewable energy capacity and has huge global potential, it said.
The technology has already been patented in the US via the United States Patent and Trademark Office’s (UNPTO) Green Fast Track programme, which gives preference to granting patents to technologies that have a high ecological impact and environmental contribution, according to TradeArabia News Service
Water Conservation Technologies
In the short term, we can’t increase our supply of water, but we can influence our consumption. The city’s ’Day Zero’ awareness campaign is targeting Cape Town citizens around how to change their behaviors. If we continue to consume water at the rate we’ve been consuming and it doesn’t rain, at a certain point in time — Day Zero — we’ll hit the 13 percent reserves, and that’s when we’ll need to take more drastic action in terms of how we allocate water.
The improvement in Water Efficiency is required, which are hovering at around 1-2% per year to address the supply-demand gap. California, for example, enacted historic new water conservation rules in 2015, mandating urban residents to reduce water use by 25 percent. Water Conservation Technologies and water conservation devices need to be adopted for the benefit of the environment and future generations like GM technologies, Micro–irrigation or drip systems, Leakage detection equipment and water consumption software.
Waterless solutions like Freedom Waterless Car Wash, water-efficient irrigation systems and horticultural software, Water efficient appliances like dishwashers, showerheads, and toilets are becoming popular.
Wastewater recovery and reuse
Wastewater recovery and reuse, on the other hand, on average uses about half the energy of desalination, and costs about half as much. Yet, while the technology exists to recover a large percent of wastewater, the world today only reuses about 4 percent of its wastewater.
Israel, despite its desert terrain, meager rainfall and population growth, currently boasts a water surplus; it is reusing 85-90 percent of its wastewater. Saudi Arabia recently announced a plan to reuse 65 percent of its wastewater. Then there’s Singapore. The island city-state is reusing 30 percent of its water — punching well above its weight in terms of water reuse policies and technologies.
Solving Singapore’s water problem by Recycling of sewage
Water security has long been a national priority in Singapore as half of its current water supplies are imported from neighboring Malaysia. “We are preparing for the day that should the water agreement expire, we should be ready to fulfill our own needs,” says Chew Men Leong, Chief Executive of the Public Utilities Board.
Singapore’s strategy for a hydrated nation is four-fold: as well as importation, it includes desalinization plants, efficient catchment of rainwater and recycling of sewage. Country’s public utilities board has developed innovative membrane technology to treat wastewater known as ‘NEWater’. Through a four-step series of barriers and membranes, wastewater is made free of solids, microorganisms, and contaminants resulting in potable water supplies for use by humans and industry. After one decade, the technology meets 30 percent of Singapore’s water needs, with plans to triple volumes by 2060.
Forward Water Technologies (Canada) offers new, efficient, low cost ways to clean and recycle heavily contaminated industrial wastewater, reducing treatment costs by more than 40%. It directly impacts a user’s revenue stream, lowers energy needs up to 20x, reduces GHG output by 30-40%, and reclaims clean water for re-use.
AI based water usage Optimization
Maia Analytica (Canada) software company provides real-time analytical tools to assist the next generation of wastewater treatment operators with proactive decision making. Its team of engineers work with facilities to identify key decision points and build AI systems to deliver operators with optimized real-time recommendations. Maia Analytica’s mission is to ease the transition to a new generation of operators that will continue to safely and efficiently protect our waterways.
FREDsense (Canada) is a world leader in portable and rapid instrumentation systems for the water industry. It specializes in analyzing water chemistry in real-time using next generation biological sensor technology. With modular and customizable sensor solutions, FREDsense is moving analytical lab analysis into the field empowering water utilities, environmental consulting firms and heavy industry to start optimizing their water sources in ways it has never been possible before.
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