Tetracycline Removal from Wastewater and Electricity Generation in Microbial Electro-Fenton System in Different Electrical Circuit Conditions

Background and purpose: Microbial electro-Fenton system as a novel technology can be employed in removal of resistant organic pollutants along with generation of renewable electrical energy through the activity of anaerobic microorganisms. This study aimed at investigating the performance of this process in treatment of synthetic wastewater containing tetracycline and generation of electricity in different electrical circuit conditions. Materials and methods: In this experimental study, a two-chambered microbial electro-Fenton reactor equipped with anodic and cathodic carbon felt electrodes and Nafion membrane, along with 2000 mg/L substrate and anaerobic sludge as inoculum in anodic chamber and 10 mg/L tetracycline in cathodic chamber was used in open, closed, and short circuit conditions. The effect of electrical circuit type on the removal efficiency of tetracycline and generation of electrical energy was investigated during the operation of the reactor. Results: Microbial electro-Fenton system was found to be more efficient in removal of tetracycline in short circuit condition due to improved generation of current density. In this study, 260 mV and 93.13 mW/m2 in current density of 695 mA/m2 were obtained in short circuit conditions. Conclusion: The study showed that the microbial electro-Fenton system can be utilized as a suitable method in removal of various pharmaceutical contaminants from wastewater while producing renewable and clean energy in open, closed, and short electrical circuits.