Sunday, May 01, 2022

Portable desalination unit that generates clear, clean drinking water without the need for filters or high-pressure pumps

Good news! However, the throughput of this new device at about 0.3L per hour leaves something to be desired.

Sufficient and reliable potable water supply going forward is probably one of the biggest real challenges of humanity! Human ingenuity can handle it!

However, this new system needs no filters or high pressure pumps. It also clears dirty water. I wonder whether this new system can be scaled to filter thousands of liters of sea water.

"... The suitcase-sized device, which requires less power to operate than a cell phone charger, can also be driven by a small, portable solar panel, which can be purchased online for around $50. It automatically generates drinking water that exceeds World Health Organization quality standards. The technology is packaged into a user-friendly device that runs with the push of one button. ...
Instead, their unit relies on a technique called ion concentration polarization (ICP) ... Rather than filtering water, the ICP process applies an electrical field to membranes placed above and below a channel of water. The membranes repel positively or negatively charged particles — including salt molecules, bacteria, and viruses — as they flow past. The charged particles are funneled into a second stream of water that is eventually discharged.
The process removes both dissolved and suspended solids, allowing clean water to pass through the channel. Since it only requires a low-pressure pump, ICP uses less energy than other techniques.
But ICP does not always remove all the salts floating in the middle of the channel. So the researchers incorporated a second process, known as electrodialysis, to remove remaining salt ions. ..."

From the abstract:
"A portable seawater desalination system would be highly desirable to solve water challenges in rural areas and disaster situations. While many reverse osmosis-based portable desalination systems are already available commercially, they are not adequate for providing reliable drinking water in remote locations due to the requirement of high-pressure pumping and repeated maintenance. We demonstrate a field-deployable desalination system with multistage electromembrane processes, composed of two-stage ion concentration polarization and one-stage electrodialysis, to convert brackish water and seawater to drinkable water. A data-driven predictive model is used to optimize the multistage configuration, and the model predictions show good agreement with the experimental results. The portable system desalinates brackish water and seawater (2.5–45 g/L) into drinkable water (defined by WHO guideline), with the energy consumptions of 0.4–4 (brackish water) and 15.6–26.6 W h/L (seawater), respectively. In addition, the process can also reduce suspended solids by at least a factor of 10 from the source water, resulting in crystal clear water (<1 NTU) even from the source water with turbidity higher than 30 NTU (i.e., cloudy seawater by the tide). We built a fully integrated prototype (controller, pumps, and battery) packaged into a portable unit (42 × 33.5 × 19 cm3, 9.25 kg, and 0.33 L/h production rate) controlled by a smartphone, tested for battery-powered field operation. The demonstrated portable desalination system is unprecedented in size, efficiency, and operational flexibility. Therefore, it could address unique water challenges in remote, resource-limited regions of the world."

From seawater to drinking water, with the push of a button | MIT News | Massachusetts Institute of Technology Researchers build a portable desalination unit that generates clear, clean drinking water without the need for filters or high-pressure pumps.




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