It’s possible to extract useful minerals, such as calcium, potassium and magnesium, from the salty brine that remains after desalinating water. Desalination process takes salt out of seawater, to address the rising global demand for clean drinking water and for agricultural use.
Damian Palin proposes to make use of all parts of the desalination process and “mine minerals from seawater” by using a collaborative metal-munching bacteria. These bacteria accumulate, precipitate, and sediment minerals out of desalination brine. During this metabolic process they create an electrical charge. This charge attracts metals from the local environment, and so minerals accumulate on the surface of the bacteria.
Desalination is a great technique for places which do not have consistent and readily available access to clean water, but are located close to sea water. A membrane-filtration technique uses reverse osmosis to remove salt from water. Pressure is applied to sea water to push it through a membrane, producing clean water on one side and leaving a concentrated salt solution, or brine, on the other side. It’s a very expensive process, often too costly for many places around the world. Places that can afford it, also have to deal with a large amount of salt brine remaining after the process. The brine that’s produced is often pumped back out into the sea, which is detrimental to the local ecology of the affected sea area.
Damian works in Singapore, which proposes to produce 900 million liters of desalinated water per day by 2060. The process will produce an equally large amount of desalination brine to take care of. At the time of her presentation at this TED conference, Damian estimated that Singapore’s seawater minerals mining industry was worth $4.5 billion, a significant economic contribution for a country that’s considered to not have any natural resources. In harmony with nature, this type of mining doesn’t pollute the Earth, as well as upcycles the perceived “waste” product that can be environmentally harmful.