Engineers at MIT and in China are aiming to turn seawater into drinking water with a completely passive device that is inspired by the ocean, and powered by the sun.
In a paper appearing today in the journal Joule, the team outlines the design for a new solar desalination system that takes in saltwater and heats it with natural sunlight.
The researchers estimate that if the system is scaled up to the size of a small suitcase, it could produce about 4 to 6 liters of drinking water per hour and last several years before requiring replacement parts. At this scale and performance, the system could produce drinking water at a rate and price that is cheaper than tap water.
As I understand it such “waste salt” is usually returned to the ocean in the form of brine. The brine is denser than the ocean water around it so it flows down the slope of the land like a river into the deeps where it eventually dilutes back into the ambient water.
Brine flows and brine pools happen naturally in some places in the ocean already. They’re common underneath sea ice - sea ice is pure water and brines flow out of it as it forms. There are brine pools in the depths of the Mediterranean because that sea has greater evaporation than it does fresh water inflow. It’s not some new horror humanity is inflicting on the ocean. If care is taken with routing the brine it shouldn’t cause much trouble to the ecosystem.
It’s already a problem in some areas. It’s the scale that we do things at that causes the problem.
CO2 also exists in large quantities by natural process, but when you increase it on a massive scale for a century, it adds up to disaster.