Low-carbon sustainable bio-electrochemical system for upgrading oilfield wastewater treatment: Comparative life cycle...

Chemical oxygen demand (COD) removal with low carbon emission is critical for sustainable oilfield wastewater management. This study performed a comparative life cycle assessment of bio-electrochemical systems (BES) against electrochemical oxidation, activated sludge (ASP), Fenton process, and reverse osmosis. BES significantly outperformed the above conventional technologies, reducing global warming potential by 79.6 % (360.3 versus 1766.0 kg CO₂ eq./kg COD) and human toxicity by 88.2 % (127.0 versus 1078.6 kg 1,4-DB eq.) compared with ASP and Fenton process, respectively. This was attributed to BES converting organic pollutants into bioelectricity to power COD degradation while avoiding chemical reagent inputs. An empirical greenhouse gas emission model and a decision framework were developed to guide technology deployment based on local infrastructure and ecological priorities. Overall, BES presents a sustainable and energy-efficient alternative for oilfield wastewater management, offering significant dual environmental benefits of effective contaminant removal and substantial carbon emission reduction.