Sustainable Management of CO2 Generated by a Wastewater Treatment Plant

A substantial CO2 emission has been generated by wastewater treatment plants (WWTPs) due to various biological processes. Since the most important consequences of increasing CO2 in the atmosphere are global warming and climate change, there is a necessity to mitigate CO2 emissions in a sustainable way, particularly, when inorganic carbon can be converted to a valuable product. This paper proposes a novel management of CO2 generated by WWTP through its capturing and converting into a fuel, which can be used in-situ. A newly developed electrochemical device, under a constant direct current (DC), was able to convert carbon dioxide to fuel at ambient conditions without additives. These conditions (temperature and pressure) seemed to be satisfied parameters to achieve the sustainable electrochemical transformation of CO2 into a green fuel (methanol). The study permitted to optimize technological parameters, such as voltage gradient, gas flowrate, input gas period, and temperature, in order to generate the best conversion of CO2 to methanol. The continuous flow device was set for final conditions resulting in the predominant methanol generation. Under room temperature, at a voltage gradient of 8 DCV/cm, 60% of CO2 found to be converted to methanol after only 20 min of influx time. Therefore, the developed electrochemical device can convert CO2 produced at WWTP into methanol, which may be used as a fuel or in denitrification facilities at the same WWTP. The proposed device is one of the useful approaches to a sustainable GHG management at WWTP, permitting to store energy and contribute to solving the global warming and climate change problems.