Engineers from the University of Colorado have created a wastewater treatment process that mitigates carbon dioxide, while also capturing greenhouse gases.

A wastewater treatment plant in Oregon. Photo by Rjgalindo/Wikipedia.The treatment method is called Microbial Electrolytic Carbon Capture (MECC), and it purifies wastewater by using an electrochemical reaction that absorbs more carbon dioxide (CO₂) than it releases. The process also creates renewable energy.

“This energy-positive, carbon-negative method could potentially contain huge benefits for a number of emission-heavy industries,” says Zhiyong Jason Ren, an associate professor of Civil, Environmental, and Architectural Engineering.

MECC uses the natural conductivity of saline wastewater to facilitate an electrochemical reaction that is designed to absorb CO₂ from both the water and the air. According to the researchers, the process transforms CO₂ into stable mineral carbonates and bicarbonates that can be used as raw materials by the construction industry. It can also be used as a chemical buffer in the wastewater treatment cycle itself or used to counter acidity downstream from the process such as in the ocean.

The reaction also results in excess hydrogen gas, which can be stored and used as energy in a fuel cell.

The study says that wastewater could be treated effectively on-site without the risks or costs typically associated with disposal.

Although according to the researchers, further research is needed to determine the optimal MECC system design and assess the potential for scalability.

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University of Colorado

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