Large amounts of wastewater containing residual antibiotics are produced in antibiotics production, but it is difficult for traditional biological wastewater treatment to efficiently treat this high concentration antibiotic wastewater. Coupled electrocatalytic and bioelectrochemical systems were proposed to treat typical β-lactam antibiotics (penicillin) wastewater. The penicillin wastewater was oxidized by a boron-doped diamond (BDD) electrocatalytic electrode and then steadily treated by a bioelectrochemical system (BES). The penicillin removal rate of the electrocatalytic system was 89%, and 79% of the residual penicillin was further removed by the BES. The maximum power density of the BES with pretreated penicillin of (1124±28) mW·m-2 was increased by 473% compared with that of the BES with raw penicillin. The total penicillin removal rate was 98% in the electrocatalytic and bioelectrochemical system. The results of the BES anode biomass and biofacies showed that Acinetobacter was the dominant bacterial group on the anode before penicillin addition, and it was the main microorganism in the formation of the anode biofilm. Bacillus is an electricity-producing bacterium with a power generation function. Penicillin inhibited the biomass of the mixed anode bacteria and the biological activity of Proteus microorganisms, which were the main electricity-producing bacteria, and reduced the biomass of Acinetobacter and Bacillus. This was the main factor affecting the power generation performance and reactor treatment effect. The pretreatment of penicillin wastewater by electrocatalytic degradation can significantly decrease its concentration, efficiently alleviate the inhibition of the BES by penicillin, and improve the biodegradability of wastewater. The coupled electrocatalytic and bioelectrochemical system is a new technology for antibiotic wastewater treatment with a high efficiency and low energy consumption.
Keywords: bioelectrochemical system(BES); boron-doped diamond(BDD); electrocatalysis; microbial fuel cell(MFC); penicillin.