Removal of High Concentrations of Veterinary Antibiotics Through Co-composting of Swine Waste

Abstract

The increasing demand for animal protein, mainly for porcine protein, has led companies and producers to investigate techniques capable of optimizing current production systems, as well as the use of drugs such as veterinary antibiotics. The incomplete absorption of these drugs by the digestive system of the animals generates effluents whose composition presents veterinary drug residues. Swine waste treatment systems (ponds) have reduced capacity to degrade these residues; thus, it is necessary to find treatment alternatives such as composting. Therefore, the aim of the current study was to evaluate the effectiveness of the composting technique in degrading 17 veterinary antibiotics often used in pig production systems. The herein adopted composting process comprised eucalyptus shavings and swine waste at the ratio 1:8 (1 kg of shavings to 8 L of swine waste). First, 25 L of swine waste were contaminated with 17 antibiotics and mixed in a bench-scale composting system for 150 days. The sample preparation consisted of the solid-liquid extraction followed by a clean-up by dispersive solid phase extraction, and then the extracts were analyzed by ultra-high performance liquid chromatography tandem mass spectrometry. Antibiotic groups such as quinolones, tetracyclines, and sulfonamides recorded fractions cumulative removal of 99.4%, 99.4% and 97.2%, respectively, at the end of the composting process. On the other hand, antibiotics such as sulfathiazole, chlortetracycline, and tetracycline recorded 100% degradation during the composting process.