Quantification of multi-class antibiotics by UHPLC-MS/MS in animal manure and fate of antibiotics during rapid composting

Massive amounts of animal waste are generated from livestock raising and proper management of this waste is critical for the elimination of manure pollutants including various gaseous, nutrients, pathogens, and antibiotics. A comprehensive multiresidue method for the analysis of 33 antibiotics from 7 prevalent classes was comparably investigated for both dairy and poultry manure. Following salting-out-assisted extraction with Acetonitrile (MeCN), the antibiotics were quantified with Ultrahigh-Performance Liquid Chromatography Tandem Mass Spectrometry (UHPLC-MS/MS) without a clean-up step. Although the physicochemical properties of selected antibiotics were quite different, the apparent recovery from dairy and poultry manure samples were 86–121% and 89–113%, respectively. Rotary drum composting was performed in closed systems with controlled aeration for the reduction of detected antibiotics and volume of manure. Two identical reactors were operated up to 20 days. After the characterization of manure samples, proper compositions for rapid composting were prepared by blending of dairy (D), broiler (B), and layer-hen (L) manures. The performances of composting process for DB and DL manure mixtures as well as B and D manures were evaluated. Time to attain the peak composting temperature (68-73°C) was reduced and higher peak temperatures were achieved in mixed manures compared to the composting of D manure alone. While the composting with high aeration rate (17±3m3.h-1) caused a decrease in composting temperature, the elevated temperature achieved with low aeration rate (3.6±0.2 m3.h-1) did not improve antibiotic reduction, and high aeration reduced the half-lives of antibiotics regardless of manure blending indicating the importance of biotic processes.