Effects of Conditioners on Sulfonamides Degradation during the Aerobic Composting of Animal Manures

Sulfonamides (SAs) is one kind of the most important pharmaceuticals occurring in the environment. As the food additive, an increase application of SAs in the production of livestock and poultry leads to amounts of SAs excreted in manure, resulting in persistent environment pollution. Our research aimed to study the effects of some conditioners(sawdust, rice straw) on SAs degradation during the aerobic composting of animal manure. The experiments were conducted for 10 manure composting treatments as follow: hog manure,10 mg·kg-1 SAs; hog manure+sawdust,10 mg·kg-1 SAs; hog manure+rice straw,10 mg·kg-1 SAs; hog manure,20 mg·kg-1SAs; hog manure+sawdust,20 mg·kg-1 SAs; hog manure+rice straw,20 mg/kg SAs; Chicken manure,10 mg·kg-1 SAs; Chicken manure+sawdust,10mg·kg-1SAs; Chicken manure,20mg·kg-1SAs; Chicken manure+sawdust, 20 mg·kg-1SAs.The degradation of four SAs,sulfamerazine(SM1),sulfachlorpyridazine(SCP), sulfadimoxine(SDM′), Sulfaquinoxaline(SQ) were evaluated. The results showed that over 60% of 4 kinds of SAs were degraded in 35d of aerobic composting. Significant degradation of SM1, SCP, SDM′, SQ were showed in treatments using conditioners than using manure alone. The reduction of 4 kinds of SAs ranged from 62.30 to 100% in all six treatments in aerobic composting, and the highest degraded rates were observed in six hog manure treatments with adding rice straws. It concluded that adding conditioners improved the degradation rate of 4 kinds of SAs during composting, which was considered as a practical and economical option for reducing antibiotic levels in animal manure before field use.