Insights into the practicability of electrochemical enhanced heterogeneous activation of peroxymonosulfate for the treatment of liquid waste during penicillin g production

The efficient mineralization of antibiotics in production waste drainage (PWD) and fermentation residue leachate (FRL) is crucial for avoiding environmental accumulation and the generation of antibiotic-resistant bacteria and genes. In this study, the penicillin G (PG) containing PWD and FRL were treated by electrochemical enhanced heterogeneous activation of peroxymonosulfate with CoFe2O4 nanoparticles (EC/CoFe2O4/PMS). The results indicated that the mineralization rate of PG did not improve significantly in EC/CoFe2O4/PMS system (39.0 %) with the same reaction condition ([CoFe2O4] = 100 mg L-1, [PMS] = 152 mg L-1, [Na2SO4] = 20 mM) of CoFe2O4/PMS system (28.1 %) coupled with 1 V cm-1 electric field. Meanwhile, the toxic intermediate product (P4) was detected. However, at the condition of catalyst saving mode (CSM, [CoFe2O4] = 50 mg L-1, [PMS] = 250 mg L-1, [Na2SO4] = 20 mM, E = 1 V cm-1), the mineralization rate of PG in artificial wastewater reached 69.1 %, which was further increased to 88.0 % and 76.5 % in the PWD and FRL, respectively. Although the removal rate of pollutants even exceeded 90 %, most of them were not meet the direct discharge requirements of China due to their high concentration in initial PWD and FRL. However, the ratio of BOD5/COD (represented the biodegradability) of PWD and FRL significantly increased from 0.18 and 0.37 to 0.47 and 0.79 at the end of the experiment, respectively, and the P4 was not detected. Therefore, EC/CoFe2O4/PMS system with CSM operation mode could eliminate PG completely and achieve deep mineralization, which improved the biodegradability of production drainage, and might achieve complete mineralization of PG through combination of bioremediation methods.