You may not spend much thought on cleaning up municipal and industrial wastewater, but you may have guessed it’s dirty. Quite dirty, in fact. Wastewater treatment produces carbon dioxide (CO2) emissions by powering the whole machinery (and this requires high amounts of energy) and by decomposing organic material within the wastewater. Luckily, it doesn’t need to be this way. Engineers have now developed an innovative wastewater treatment process that not only mitigates CO2 emissions, but actively captures greenhouse gases as well. This new treatment method purifies wastewater in an environmentally-friendly fashion by using an electrochemical reaction that absorbs more CO2 than it releases while creating renewable energy in the process. Zhiyong Jason Ren, senior author of the study, which was recently published in the journal Environmental Science and Technology, says: “This energy-positive, carbon-negative method could potentially contain huge benefits for a number of emission-heavy industries.”