News Feature | December 9, 2015

Shockwaves Power MIT's New Desalination Process

Sara Jerome

By Sara Jerome,

A new innovation from Massachusetts Institute of Technology researchers could improve desalination using shockwaves.

The new process relies on “shockwaves to separate contaminated or salty water into two separate streams, with a natural barrier between each one,” Gizmag reported. This separation makes it possible to “repurpose salt water and even toxic wastewater for drinking purposes, without the long-term sustainability obstacles of traditional desalination processes,” Digital Trends reported.

A more detailed description of the process, per Gizmag:

The MIT process sends water through an inexpensive porous material made of tiny glass particles, and across membranes or electrodes sandwiched on each side. As electricity is applied to the system, the salty water divides into zones of depleted or enriched salt concentration. Increasing the current generates a shockwave between the two zones, effectively adding a physical barrier that creates a flow of fresh water on one side and salty or contaminated water on the other.

The upside of this process is that no filter is necessary. Many desalination processes rely on a membraneless filter which presents challenges if it becomes clogged. Boiling methods are also used in place of a filter, but those require a considerable amount of energy.

The new approach is described in the journal Environmental Science and Technology Letters, in a paper by professor of chemical engineering and mathematics Martin Bazant, graduate student Sven Schlumpberger, undergraduate Nancy Lu, and former postdoc Matthew Suss.

The new process could find uses in the energy sector, according to a statement from MIT.

“One possible application would be in cleaning the vast amounts of wastewater generated by hydraulic fracturing, or fracking. This contaminated water tends to be salty, sometimes with trace amounts of toxic ions, so finding a practical and inexpensive way of cleaning it would be highly desirable. This system not only removes salt, but also a wide variety of other contaminants — and because of the electrical current passing through, it may also sterilize the stream,” the report said.

Schlumpberger noted: “The electric fields are pretty high, so we may be able to kill the bacteria.”

For similar stories, visit Water Online’s Desalination Solutions Center.