The widespread use of antibiotics in feed results in a large number of antibiotic residues in feces. Composting technology can degrade these residual antibiotics. A pilot-scale aerobic composting device was used to analyze the antibiotic residues and composting degradation characteristics of four types of feces (maggot manure, chicken manure, pig manure, and cow manure). Results showed that sulfonamides (SAs), fluoroquinolones (FQs), tetracycline (TCs), and macrolides (MAs) were the main antibiotics, and different type of feces had different dominant antibiotics. The contents of FQs and oxytetracycline (OTC) were none on the seventh day of the compost, and their degradation rates were the fastest. After composting, the degradation rate of doxycycline (DOX) in the four types of fecal composts was more than 85%. Meanwhile, the degradation rates of SAs in chicken, pig, and cow manure composts were also more than 80%, which was much lower in the one in maggot manure compost. MAs were only found in maggot manure, and the degradation rate was 70.79% after composting. Correlation analysis indicated that the water content and bulk density were the most important environmental factors affecting the degradation rates of antibiotics in the four types of fecal composts.
Keywords: antibiotics; composting; degradation; environmental factors; feces.