In situ electrochemical oxidation in electrodialysis for antibiotics removal during nutrient recovery from pig manure digestate

This study proposed a novel electrodialysis (ED) system, named anode-ED, which can utilise the anode of ED in situ to electrochemically remove the antibiotics during nutrient (N and P) recovery from animal manure digestate. The oxidation of targeted antibiotics (sulfadiazine, SD; and tetracycline, TC) by the anode of ED was first assessed in a single-compartment reactor containing only one pair of ED electrodes. The results showed that Cl2 generated from the anode played the primary role in SD and TC removal. The anode-ED was then established based on a conventional ED process, in which the wastewater successively flowed into the anode compartment and the dilute compartment of the reactor. There was no observable difference in N and P recovery between the anode-ED and conventional ED, while the targeted antibiotics in the anode-ED were removed much more efficiently, with SD and TC removed in the 30 and 60 min, respectively, in comparison with conventional ED. In addition, in the anode-ED, membrane fouling was mitigated due to gas bubbling and the pathogenic microorganism indicators (E. coli and Enterococcus) were inactivated efficiently. Regarding the formation of disinfection by-products, only 134 ?g/L of trihalomethanes and 192 ?g/L of haloacetic acids were detected in the effluent due to membrane sorption, far less than those generated during conventional electrochemical oxidation and chlorination of wastewater. This study shows that anode-ED is a promising option to remove the antibiotics in an ED system, simultaneously achieving nutrient recovery, antibiotics removal, membrane fouling mitigation and pathogen inactivation.

Automated summary

The study introduced a novel electrodialysis system, anode-ED, which effectively removes antibiotics from animal manure while recovering nutrients. Compared to conventional ED, anode-ED can more efficiently remove targeted antibiotics, reduce membrane fouling, and efficiently deactivate pathogenic microorganisms.