Antibiotics are non-biodegradable drugs that inhibit the expansion and growth of microorganisms. Especially with the prevalence of Covid-19, the consumption of antibiotics has increased. Therefore, the presence of most prescribed antibiotics from ß-lactams including amoxicillin and cephalexin were studied at two municipal WWTPs in Isfahan. The analytical method was to extract antibiotics from the aqueous phase and then detected them via HPLC/UV. Samples were collected from 2 WWTPs for 13 sampling periods over 2 months between February and March 2020 during the outbreak of Covid-19. In WWTP A, the average concentration of amoxicillin in influent, effluent, and its removal efficiency was 509.64 ± 161.97 µg/L, 352.96 ± 203.88 µg/L, 34.35 ± 31.38%, and the average concentration of cephalexin in influent, effluent, and its removal efficiency was 189.42 ± 176.06 µg/L, 32.6 ± 49.59µg/L, 78.75 ± 23.81%, respectively. In WWTP B, the average concentration of amoxicillin in influent, effluent, and its removal efficiency was 2134.82 ± 3031.53µg/L, 401.09 ± 205.86µg/L, and 54.82 ± 33.29%, respectively. Also, the average concentration of cephalexin in influent, effluent, and its removal efficiency was 183.69 ± 123.48 µg/L, 23.01 ± 40.71 µg/L, and 87.65 ± 21.76%, respectively. According to Mann–Whitney test results, the concentration of antibiotics in both WWTPs had significant differences ( p-value < .05), and according to results from the Spearman test no correlation between removal efficiency of antibiotics with other principles wastewater parameters was observed.

Background: In recent years, the world has faced with the COVID-19 pandemic, followed by a significant increase in the use of antibiotics to control the COVID-19 and other secondary infections. The nonbiodegradable characteristics of antibiotics and their residues in the environment leads to increased microbial and drug resistance. Therefore, due to the high importance of antibiotics, two antibiotics, ampicillin and penicillin G, were studied in Isfahan municipal wastewater treatment plants (WWTPs). Methods: Sampling was performed for two months during 13 sampling periods and antibiotics were measured using high-performance liquid chromatography with UV detector (HPLC/UV) instrument. Results: Ampicillin and penicillin G were identified in all samples taken from the both WWTPs. The average concentration of penicillin G in WWTP E and S at the influent, effluent and its removal efficiency were 1050.54±761.43 µg/L, 52.89±49.27 µg/L, 89.80±19.42%, 2055.12±1788.08 µg/L, 143.01±162.59 µg/L and 82.76±21.85%, respectively. Also, the average concentration of ampicillin in WWTP E and S in the influent (796.44±809.6 and 447.1±322.39 µg/L), effluent (48.94±24.25 and 90.31±75.91 µg/L), and its removal efficiency (86.22±19.84% and 66.85±24.88%) were determined. Conclusion: In two studied WWTPs, the concentration of antibiotics was higher during the COVID-19 pandemic in comparison with previous studies. The statistical analysis showed that there was no significant relationship between the concentration of antibiotics in WWTPs (P<0.05). Also, the statistical results indicated that the correlation is not significant between removal efficiency of antibiotics and removal efficiency of wastewater main parameters.

Antibiotics are non-biodegradable drugs that used to inhibit the expansion and growth of microorganisms. The presence of antibiotics and their residues in the environments has resulted in an increased universal concern due to their contrary impacts on human healthiness and also the environment. Specially with the prevalence of Covid-19, the consumption of antibiotics to treat or prevent secondary infections have increased. Therefore, the presence of most prescribed antibiotics from ß-lactam class including amoxicillin and cephalexin were studied at two municipal WWTPs in Isfahan. Analytical method was extracted and then detected via HPLC/UV. Samples were collected from 2 wastewater treatment plants (WWTPs) on 13 sampling periods over 2 months on February and March 2020 during the outbreak of Covid-19. In WWTP A, the average concentration of amoxicillin in influent, effluent, and its removal efficiency was equal to 509.64 ± 161.97µg/l, 354.37 ± 201.41µg/l, 33.69 ± 30.22%, and the average concentration of cephalexin in influent, effluent, and its removal efficiency was 189.42 ± 176.06µg/l, 44.35 ± 43.72µg/l, 64.61 ± 26.52%, respectively. In WWTP B, the average concentration of amoxicillin in influent, effluent, and its removal efficiency was equal to 2134.82 ± 3031.53µg/l, 401.09 ± 205.86µg/l, 54.82 ± 33.29%, and the average concentration of cephalexin in influent, effluent, and its removal efficiency was183.69 ± 123.48µg/l, 40.64 ± 33.02µg/l, 72.89 ± 19.45, respectively. According to statistical points of view, the concentration of antibiotics in both WWTPs had significant differences and no critical correlation between removal efficiency of antibiotics with other principle wastewater parameters was observed.