Abstract: As composting is a common agricultural practice of preparing the manure for farmland application, understanding fate and behavior of the residual antibiotics in the manure under composting will help environmental risk assessment of antibiotics. Swine manure was composted under four different modes of aeration, including natural ventilation, pile-turning, mechanical aeration, pile-turning plus mechanical aeration. Changes in temperature of the piles and germination index were monitored during the composting process. Potential influences of aeration mode, external temperature and initial antibiotic concentration on removal efficiency of four commonly-used veterinary antibiotics (sulfamethazine, oxytetracycline, chlortetracycline and tiamulin) were examined in detail. Results indicate that the aeration mode of pile-turning plus mechanical aeration promoted maturity of the compost, as evidenced by the highest pile temperature (63 ^oC) and the longest duration of high-temperature period (4 d above 60 ^oC). Most of the antibiotics were degraded in the temperature-rising phase and the high-temperature phase of the manure composting process.The degradation rate increased with the temperature, associated with aeration mode. The initial concentration of 100 mg•kg^-1 of all the four  antibiotics did not retard much the process of composting mode. After 28 d of high-temperature composting, the concentration of sulfamethazine, oxytetracycline,chlortetracycline,and tiamulin dropped remarkably from 100 mg•kg^-1 to 1.90, 7.20, 6.64 and 8.75 mg•kg^-1, respectively.

Key words: high-temperature composting, swine manure, antibiotics, removal efficiency