Wastewater treatment captures CO2 and produces energy

According to the research, published recently in the journal Environmental Science and Technology, Microbial Electrolytic Carbon Capture (MECC) involves an electrochemical reaction that absorbs more CO₂ than it releases, creating a source of renewable energy in the form of hydrogen gas at the same time.

“This energy-positive, carbon-negative method could potentially contain huge benefits for a number of emission-heavy industries,” said Zhiyong Jason Ren, an associate professor of civil, environmental, and architectural engineering at CU-Boulder and senior author of the study.

Traditional wastewater treatment contributes to CO₂ emissions through both the decomposition of organic material, and the fossil fuels burned to power energy-intensive treatment machinery.

MECC uses the natural conductivity of saline wastewater to facilitate an electrochemical reaction designed to absorb CO₂ from water and air. According to the team at CU-Boulder, the process transforms the CO₂ into stable mineral carbonates and bicarbonates. These can then be used as raw materials in the construction industry, a chemical buffer in the wastewater treatment cycle itself, or to reduce acidity downstream of the process such as in the ocean.