New brine treatment promises cleaner planet, more water

Staff Writer | May 09, 2019
Scientists have found a way to treat super-salty brine generated in the oil and gas industry.

Reducing pollution and saving water are the twin benefits of a new process to treat brine. 

Brine, which is difficult treat, contains more dissolved salts than ocean water, and is of growing environmental concern as a pollutant of fresh-water sources. 

However, a team of engineers from Columbia University in the United States say they have developed a radical new approach to desalinating brine.

The method, known as "temperature swing solvent extraction" (TSSE), involves mixing the brine with an amine solvent. Amine is an organic compound derived from ammonia.

Scientists say the method can desalinate brines that are up to seven times more concentrated than seawater. This is more than the two existing methods can achieve – desalination and the water-evaporation method.

The brine is mixed with the solvent, which rises to the top. After being placed in a bath at room temperature, the solvent is decanted from the mixture. The bath temperature provides a ‘swing’ which de-mixes the processed water from the solvent. When the solvent releases the water, it sinks to the bottom, where it can be collected.

Assistant professor Ngai Yin Yip, who published the research, said: "Our results show that TSSE could be a disruptive technology – it's effective, efficient, scalable, and can be sustainably powered.”

Crucially, the solvent method is powered by low-grade heat of under 70 degrees Celsius, which means it is far less energy-intensive and can remove up to 98.4% of the salt in brines and recover high amounts of water.

"We think TSSE will be transformational for the water industry,” he said. "We can eliminate the pollution problems from these brines and create cleaner, more usable water for our planet."

 

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