Biodegradation of Tetracycline and Ciprofloxacin in aerobic composting using different microbial sources

Abstract

Abstract The objective of this study was to evaluate the degradation of tetracycline (TC) and ciprofloxacin (CIP) during in-vessel composting in three different ratios of organic waste (OW), rice husk (RH), and return activated sludge (RAS) obtained from antibiotic industry wastewater treatment plant as a microbial source. The composting process was carried out in three cylindrical reactors (R1, R2, and R3) with a volume of 35.5 L. The OW/RH ratio was adjusted to 2:1, 1.4:1, and 1:1, and the RAS was added as a microbial source and to adjust the moisture content (MC). After the compost maturation phase, various concentrations of antibiotics were added to the different reactors. The HPLC method was used to measure the concentration of residual antibiotics. The physical, chemical, and bacterial properties of the compost were also analyzed throughout the process using standard methods. The findings showed that the removal efficiencies of TC were 85%, 90%, and 92.5% in R1, R2, and R3, respectively, while those of CIP were 75%, 77.5%, and 82.5% after 92 days. It was observed that using microbial sources containing antibiotic-resistant bacteria (sludge from an antibiotic wastewater treatment plant), fungi, and actinomycetes in the composting process can be an effective method for the biodegradation of antibiotics in contaminated environments.