The role of operating parameters and oxidative damage mechanisms of advanced chemical oxidation processes in the combat against antibiotic-resistant bacteria and resistance genes present in urban wastewater

Abstract

An upsurge in the study of antibiotic resistance in the environment has been observed in the last decade. Nowadays, it is becoming increasingly clear that urban wastewater is a key source of antibiotic resistance determinants, i.e. antibiotic-resistant bacteria and antibiotic resistance genes (ARB&ARGs). Urban wastewater reuse has arisen as an important component of water resources management in the European Union and worldwide to address prolonged water scarcity issues. Especially, biological wastewater treatment processes (i.e. conventional activated sludge), which are widely applied in urban wastewater treatment plants, have been shown to provide an ideal environment for the evolution and spread of antibiotic resistance. The ability of advanced chemical oxidation processes (AOPs), e.g. light-driven oxidation in the presence of HO, ozonation, homogeneous and heterogeneous photocatalysis, to inactivate ARB and remove ARGs in wastewater effluents has not been yet evaluated through a systematic and integrated approach. Consequently, this review seeks to provide an extensive and critical appraisal on the assessment of the efficiency of these processes in inactivating ARB and removing ARGs in wastewater effluents, based on recent available scientific literature. It tries to elucidate how the key operating conditions may affect the process efficiency, while pinpointing potential areas for further research and major knowledge gaps which need to be addressed. Also, this review aims at shedding light on the main oxidative damage pathways involved in the inactivation of ARB and removal of ARGs by these processes. In general, the lack and/or heterogeneity of the available scientific data, as well as the different methodological approaches applied in the various studies, make difficult the accurate evaluation of the efficiency of the processes applied. Besides the operating conditions, the variable behavior observed by the various examined genetic constituents of the microbial community, may be directed by the process distinct oxidative damage mechanisms in place during the application of each treatment technology. For example, it was shown in various studies that the majority of cellular damage by advanced chemical oxidation may be on cell wall and membrane structures of the targeted bacteria, leaving the internal components of the cells relatively intact/able to repair damage. As a result, further in-depth mechanistic studies are required, to establish the optimum operating conditions under which oxidative mechanisms target internal cell components such as genetic material and ribosomal structures more intensively, thus conferring permanent damage and/or death and preventing potential post-treatment re-growth.

Diversity of β-lactam resistance genes in gram-negative rods isolated from a municipal wastewater treatment plant

“…Diverse genes that encode resistance to all major classes of antibiotics have been identified in sewage (Zhang et al 2009). The efficiency of removing ARGs during the wastewater treatment process depends on the treatment technology and the sources of sewage coming to a WWTP (hospital, municipal effluent) (Novo et al 2013; Barancheshme and Munir 2017;Michael-Kordatou et al 2018). These genes have been found in both environmental and pathogenic strains.…”

UV-C/H2O2 and Sunlight/H2O2 in the Core of the Best Available Technologies for Dealing with Present Dares in Domestic Wastewater Reuse

“…The UV radiation may disfigure DNA, conducting to the curb of cell replication and, in situation of fatal injections, to a deprivation of reproducibility. While accepting UV for disinfecting wastewater has expanded considerably during the previous two decades, investigating on the capability of the UV technology to reduce ARB & ARGs is at most progressing throughout the last few years [13] [19]; however, in the situation of ARGs, extended period of UV/H 2 O 2 treatment appears to be requested for their efficient reduction. Plus, the probability of employing natural sunlight instead of UV lamps, to catalyze the production of • OH throughout the method, may lead to a low-cost usage [5].…”

Removal of cephalexin from artificial wastewater by mesoporous silica materials using Box-Behnken response surface methodology

“…These methods include chemical oxidation [21], biodegradation [22] and physical processes [23,24]. Adsorption is the most applied physical-chemical processes of removal of emerging contaminants from aqueous solutions [25][26][27][28][29], due to its low initial cost for implementation, simplicity and flexibility of the system, easy operation [22,[30][31][32][33].…”