Access to potable drinking water remains one of the most pervasive - yet completely solvable - problems facing humanity. Water.org estimates that 780 million people worldwide lack access to clean drinking water and 3.4 million die each year from water related diseases.
Add to that these statistics: About 97.5% of all water on Earth is saltwater, which, unless treated, can't be consumed by humans or used to grow food. That leaves only 2.5% freshwater. But almost all of the freshwater (over 99%) is inaccessible by humans because it is frozen in the ice caps, dispersed throughout the soil, or trapped deep underground. This leaves less than 1% of 2.5% of all water on Earth available for human use.
The desalination of seawater, a process which removes salts from saline water and makes it suitable for human consumption and agriculture, remains one of the most promising solutions to our water woes. In Jeddah, Saudi Arabia, where I currently live, about half of the drinking water is desalinated water from the Red Sea.
One desalination process, reverse osmosis, uses high pressure to force seawater through a membrane to remove salts and yield clean water. This process is expensive, energy-intensive, and produces a concentrated salt solution, or brine, that must be disposed of.
The most obvious disposal solution is to dump the brine back into the ocean from where it came. Sounds harmless, right? Well, no. Altering the chemistry (in this case the salinity) of the nearby aquatic ecosystems even a tiny bit can have devastating consequences for the local ecology. As the world desalinates more and more seawater, more and more brine will need to be dealt with.
Damian Palin, a research engineer at the Singapore Institute of Manufacturing Technology, is working with bacteria and other micro-organisms to solve this problem.
As certain bacteria metabolize, they accumulate minerals on their surface, a process known as bio-mineralization. The negative charge on their surface attracts positively charged metals like calcium, potassium, and magnesium (which are contained in salts) from their immediate surroundings. When introduced into the desalination brine, the bacteria cause these metals to precipitate out (fall to the bottom) and can then be collected.
This not only solves the brine disposal problem, but has the added benefit of providing minerals for human consumption. If Singapore reaches their goal of producing 900 million liters of desalinated water per day by 2060, this could translate into a mining industry in the billions of dollars for a country that does not have traditional mineral resources.
According to Mr. Palin, this is the beginning of “a mining industry that is in harmony with nature.”
Check out his video here.