Connecting The Dots Project
Low cost and simple, solar-powered water desalination
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The global population is projected to reach 9.9 billion by 2050, with many facing water shortages. According to UNICEF, over 2 billion people reside in nations with insufficient access to water supply now. As early as 2025, half of the world's population may reside in regions grappling with water scarcity. By 2030, as many as 700 million people could face displacement due to severe water scarcity. By 2040, roughly 25% of children worldwide will be residing in areas characterized by extremely high water stress. Understandably, the technology to solve the water shortage issue has been one of the top priorities for researchers around the world.
Let's start with our most common question. The ocean covers about 71% of the Earth's surface. Why can t we use ocean water to help with water shortages?
- High costs compared to other water sources
- Substantial energy consumption that contributes to climate change
- Negative environmental impacts from brine disposal
- Differences in taste and quality may not appeal to everyone.
So how expensive is the desalination processed water currently?
- $1 to well over $2 to produce one cubic meter (264 gallons) of desalted water from the ocean
- Freshwater sources can be as cheap as 10 to 20 cents per cubic meter. (the cost may vary depending on location and tech availability.)
What makes the desalination so costly and challenging?
The challenge lies in the HIGH ENERGY DEMAND of water desalination. Salt readily dissolves in water, creating robust chemical bonds that are challenging to disengage. Both the energy required and the technology for desalination are costly. Additionally, numerous attempts have faced challenges related to equipment fouling due to salt accumulation, leading to increased complexity and costs.
A breakthrough:
A joint team of researchers from MIT and Jiao Tong University in Shanghai has found a solution to salt accumulation, resulting in a more efficient and cost-effective solar desalination system compared to previous methods. This innovative approach can also be applied to treat polluted wastewater or produce steam for medical instrument sterilization, all powered solely by sunlight. This user-friendly device surpasses World Health Organization water quality standards and eliminates the need for frequent filter replacements, making it suitable for remote and resource-limited areas. It features a layered structure with dark material to absorb heat, a thin water layer, and a perforated layer above a salty water reservoir. Natural convection between the layers allows salt exchange, preventing accumulation and ensuring efficiency. The approach holds significant promise because of its exceptional energy efficiency, operational robustness, and cost-effectiveness. It enables affordable and passive desalination, generating fresh water from high-salinity source waters like seawater, brine, or brackish groundwater.
“Unlike other designs with reliability issues, we use natural convention, relying on the geometry of the device. It was completely constructed from household materials we sourced through Amazon. By my estimates, it will cost about $4 for one square-meter device,” added the researcher.
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