The global water crisis is wreaking havoc on communities worldwide. The United Nations estimates that 2.1 billion people live without safe drinking water in their homes. Because people with access to clean water have a better chance of escaping poverty, fending off disease, and pursuing an education, the water crisis has severe implications that can limit health and economic prosperity.
Furthermore, scientists predict that droughts will become more frequent and severe in the upcoming century in the face of climate change. Increased droughts could spark violent conflicts in water-stressed regions. Fortunately, researchers are working toward solutions that will provide clean drinking water to even the most remote corners of the globe.
Potable Water from Salt Water
Desalination technologies are quickly becoming a necessity in at-risk areas. The most widely used desalination processes use reverse osmosis. Although reverse osmosis is energy efficient, it doesn’t work well on water with very high saline contents. Other desalination processes use external heat sources. However, these are not always readily available.
To make desalination more viable for widespread use, the technology must become more energy efficient and less costly. At the same time, it must not require chemicals that could detrimentally affect the environment or human health.
Researchers from Center for Nanotechnology-Enabled Water Treatment (NEWT), a multi-institutional engineering research center based at Rice University in Texas, developed a system that could potentially be used off-grid in both remote areas and domestic settings. Known as nanophotonics-enabled solar membrane distillation (NESMD), this system uses solar energy and nanoparticles to make salt water drinkable.
“The integration of photothermal heating capabilities within a water purification membrane for direct, solar-driven desalination opens new opportunities in water purification,” says Menachem Elimelech, NEWT’s lead researcher for membrane processes.
With the NESMD system, the heat source is the membrane itself. The nanoparticles, which are embedded on one side of the membrane, use sunlight to heat the water and drive the desalination process.
“Instead of heating the water before it comes into the module, you heat it on the membrane surface itself. One of the big advantages is that it can be used anywhere because it’s dependent on sunlight,” explains Akshay Deshmukh, a Ph.D. student in Elimelech’s lab at Yale.
Although this technology is still in early stages, potential uses include treating water from fracking and gas extraction operations as well as household water in less developed areas.
Starch and Solar
NEWT is not the only research center exploring water-related applications of solar power. In China, researchers at Dalian University of Technology are looking at another form of solar technology to produce drinking water. The research team is implementing the use of carbon nanosheets made from starch. This material is abundant, inexpensive, renewable, and doesn’t require hazardous materials.
These carbon nanosheets connect the desalination process to solar energy. The nanosheets are fashioned into electrodes for a capacitive deionization (CDI) system, which combines the desalination process with energy storage for maximum energy efficiency. While CDI is not a new field, this research has resulted in improved energy efficiency, cost savings, and safety.
The CDI desalination process occurs in two phases. The first phase consumes energy while the second phase generates energy. Because the energy can be stored and can actually be used to partially power the first phase, it results in huge efficiency gains. Pairing CDI systems with solar panels could facilitate their implementation in areas without electric grids while reducing fuel costs and greenhouse gas emissions.
Although the system must be refined before being brought to market, it’s a promising step toward bringing clean water to vulnerable communities worldwide. Furthermore, the researchers’ holistic approach illustrates the importance of considering energy efficiency, convenience, and safety when designing new technologies.
Drinking Water from Air
Zero Mass Water is a startup that makes solar panels which pull clean drinking water from the air. The panel arrays, known as Source, use sunlight to harvest water from air vapor. The harvested vapor is sterilized, turned to liquid, and then stored in a reservoir connected to a home or public faucet.
From an orphanage in Lebanon to multimillion-dollar mansions in California, Zero Mass Water has installed Source in eighteen different countries. The cost of each solar panel is about $2,500 including installation. Each panel delivers about two-five liters of water daily, which is equivalent to about ten water bottles.
Zero Mass Water works with developers, local governments, and nonprofits to deliver their product to at-risk communities.
Cody Friesen, material scientist and CEO at Zero Mass Water, is a former engineering and materials science teacher at Arizona State University. He sees the company’s technology as a solution for water crises around the world, including poverty-stricken areas in Morocco, Egypt, and India.
According to Friesen, “Today it takes far less energy (effectively none, since it’s entirely solar powered) to create drinking water with Source than any other mechanism.”
What technologies do you think are most promising for combating the global water crisis?
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Alblaghti, Eva. (6 Feb 2018). Clean water and green energy: Making desalination practical. Yale Environment Review.
Bendix, Alex. (8 Jan 2019). These $2,000 solar panels pull clean drinking water out of the air, and they might be a solution to the global water crisis. Business Insider.
Goode, Lauren. (28 Nov 2017). How Zero Mass is using solar panels to pull drinkable water directly from the air. The Verge.
Weir, William. (23 Mar 2018). Using solar power to bring clean drinking water to remote areas. Yale News.