Simultaneous efficient removal of tetracycline and mitigation of antibiotic resistance genes enrichment by a modified activated sludge process with static magnetic field

• Published in: Water research (Oxford) Vol. 262; p. 122107
• Main Authors: Zhu, Yuan-Mo, Chen, Yongsheng, Lu, Hewei, Jin, Kai, Lin, Yuan, Ren, Hongqiang, Xu, Ke
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.09.2024
• Subjects: Activated sludge; Animals; Anti-Bacterial Agents - pharmacology; Antibiotic resistance genes; Bacteria - genetics; Bacteria - metabolism; Biodegradation, Environmental; Drug Resistance, Microbial - genetics; Magnetic field; Magnetic Fields; Metagenomics; Sewage; Swine; Swine wastewater; Tetracycline; Tetracycline - pharmacology; Waste Disposal, Fluid - methods; Wastewater - chemistry; Activated sludge; Metagenomics; Swine wastewater; Magnetic field; Antibiotic resistance genes; Tetracycline
• ISSN: 0043-1354; 1879-2448; 1879-2448
• DOI: 10.1016/j.watres.2024.122107

•SMF increased the TC removal efficiency of activated sludge.•SMF enhanced electrostatic interactions between TC and activated sludge.•SMF enriched functional bacteria related to TC biodegradation.•Enhanced AMO- and CYP450-mediated TC metabolisms were achieved under SMF.•SMF mitigated the enrichment and spread of ARGs. To address the increasing issue of antibiotic wastewater, this study applied a static magnetic field (SMF) to the activated sludge process to increase the efficiency of tetracycline (TC) removal from swine wastewater and to reveal its enhanced mechanisms. The results demonstrated that the SMF-modified activated sludge process could achieve almost complete TC removal at sludge loading rates of 0.3 mg TC/g MLSS/d. Analysis of zeta potential and extracellular polymeric substances composition of the activated sludge revealed that SMF increased electrostatic interactions between TC and activated sludge and made activated sludge has much more binding sites, finally resulting in the increased TC biosorption. Metagenomic analysis showed that SMF promoted the enrichment of ammonia-oxidizing bacteria, TC-degrading bacteria, and aromatic compounds-degrading bacteria; it also enhanced ammonia monooxygenase- and cytochrome P450-mediated TC metabolism while upregulating functional genes associated with oxidase, reductase, and dehydrogenase - all contributing to increased TC biodegradation. Additionally, SMF mitigated the enrichment and spread of antibiotic resistance genes (ARGs) by decreasing the abundance of potential hosts of ARGs and inhibiting the upregulation of genes encoding ABC transporters and putative transposase. Based on these findings, this study demonstrates that magnetic field is an enhancement strategy with great potential to relieve the harmful impacts of the growing antibiotic wastewater problem on human health and the ecosystem. [Display omitted]