Sulfate radical-based processes for removal of antibiotics and antibiotic-resistant bacteria from water

Bacterial resistance to antibiotics is one of the current research trends in environmental chemistry and microbiology. In terms of number of publications, the topic of antibiotic resistance genes (ARGs) ranks 3rd in environmental topics, behind climate change and the COVID-19 pandemic. ARGs are also the topic of the present project, which targets the hotspots of ARG spread - wastewater treatment plants (WWTPs). Urban WWTP discharges to surface water have been identified as clear hot spots for the spread of ARGs in the environment. Hospital wastewater often contains so-called multidrug-resistant bacteria that possess several ARGs simultaneously. In practice, infections with multidrug-resistant bacteria are not curable even with a combination of antibiotics and end in patient deaths. Hospitals therefore resort to sophisticated disinfection measures both indoors and in terms of wastewater disinfection. Despite drastic measures (e.g. chlorination), hospital effluents contain significant amounts of ARGs when entering the municipal WWTP, some of which pass through the WWTP and become part of the WWTP effluent to surface waters. Similarly, antibiotic residues can be present at concentrations in excess of 1 µg/l in WWTP effluent. Antibiotics are one of the newly identified micropollutants. Their negative impact on the environment consists both in their ecotoxicity to aquatic organisms and their selective effect on bacterial communities in terms of spreading ARGs. Although most existing studies do not confirm the correlation between background concentrations of antibiotics and ARGs, there is still no consensus in scientific circles due to the low number of such studies. It is therefore appropriate to pay close attention to both factors, as the potential for harm from the massive spread of ARGs in bacterial communities is enormous. The aim of the present ARGASO project is to optimise processes based on oxidative water treatment using sulphate radicals (SR-AOP) to purify WWTP effluents specifically from antibiotic and ARG residues. Sulphate radicals are a powerful oxidant with the potential to succeed in the more difficult part of this task, which is not only the bactericidal effect but also the inactivation of bacterial genetic material. Computational and experimental techniques at many levels of complexity will be used to achieve this goal. Computational approaches (DFT, QSAR) will provide guidance for the behavior of oxidant molecules and target pollutants (including genetic material) in a simplified matrix of model wastewater. The functional arrangements (sulfate radical and activator sources) will be transferred to real wastewater experiments where they will be validated from a kinetic point of view. As part of the project, 3 WWTPs in the Liberec region will be monitored to capture the daily and seasonal variability of antibiotic and ARG concentrations. One of the monitored WWTPs will be selected as a matrix for experimental confirmation of the effectiveness of the developed technology for antibiotic and ARG elimination. The output of the project will be several impacted publications and an "SR-AOP Technology Guide" for designing tertiary stages of wastewater treatment using SR-AOP. In the long term, this project will foster continued synergistic collaboration between US and Czech scientists in the field of SR-AOPs and will facilitate the creation of new international connections between scientists and students working in related fields at different institutions. The ARGASO project builds on the excellent basic research results achieved during the LTAUSA18078 project. This project has significantly advanced the current state of knowledge of persulfate systems and developed methodological approaches for their further study. The ARGASO project will build on the results achieved and aim to up-scaling wastewater oxidation by the sulphate radical to operational scale.