Researchers have developed an innovative wastewater treatment process that absorbs CO2, creates renewable energy and provides raw materials for the construction industry.

The treatment method, called Microbial Electrolytic Carbon Capture, uses the conductivity of saline wastewater to facilitate an electrochemical reaction that absorbs CO2 from both the water and air. The process transforms CO2 into stable mineral carbonates and bicarbonates that can be used as raw materials by the construction industry.

The reaction also creates hydrogen gas, which can be stored and harnessed as energy in a fuel cell, the researchers said.

“This energy-positive, carbon-negative method could potentially contain huge benefits for a number of emission-heavy industries,” study senior author Zhiyong Jason Ren from the University of Colorado at Boulder said.

Dr Ren said further research was needed to determine the optimal system design and assess the potential for scalability.

“The results should be viewed as a proof-of-concept with promising implications for a wide range of industries,” he said.

The researchers said the new research, published in the journal Environmental Science and Technology, was exciting because wastewater treatment was typically a source of CO2 – through the fossil fuels used to power treatment facilities and directly from decomposition of organic materials in wastewater.

The carbonates produced by MECC could also be used to mitigate rises in ocean acidity.

“This treatment system generates alkalinity through electrochemical means and we could potentially use that to help offset the effects of ocean acidification,” co-author Greg Rau from the University of California said.