Harnessing UV-C photoassisted AOPs: Amoxicillin degradation, disinfection by-products formation, and Enterococcus faecalis inactivation in aquaculture water

Resumen

The continuous growth of global population has promoted the development of new aquaculture techniques for enhancing food supply. Modern approaches, such as Recirculating Aquaculture Systems (RAS), present new challenges concerning the elimination of chemical substances and pathogens that appear because of their operation. In this study, the simultaneous removal of amoxicillin and water disinfection was evaluated using different UV-C photoassisted Advanced Oxidation Processes (AOPs). The processes involved oxidants such as hydrogen peroxide, peracetic acid, sodium hypochlorite, potassium peroxymonosulfate, and sodium persulfate. The optimization of radiation and oxidant dosage was assessed in a batch system photoreactor using simulated aquaculture water. Moreover, the disinfection potential of these treatments, as well of the production of disinfection by-products (DBPs), phytotoxicity generation and matrix interaction are also addressed. Finally, a first approximation to the reaction mechanism is carried out via scavenging studies. Results show that 10 W/m2 of UV-C and optimized dosages in the 0.1-3.2 mM range of oxidant eliminate at least 80 % of amoxicillin in 2 h of operation. Disinfection was achieved in 1 min of treatment and maintained for at least two weeks after storage. While DBPs and matrix parameters variation were minimal. Scavenging study shows that HO center dot, 1O2, and SO4 center dot radicals are the main ones involved in antibiotic degradation. The optimization of operation conditions sets the path towards scale-up of the process in continuous systems, with the objective of application of the process in real aquaculture water.