Effect of Antibiotics and Thermophilic Pre-Treatment on Anaerobic Co-Digestion of Pig Manure and Corn Straw

The excessive use of antibiotics in the pig breeding industry leads to the accumulation of antibiotic residuals in the environment, which is attributed to the improper treatment of livestock excrements. Sulfamethoxazole (SMX) and Norfloxacin (NOR) are antibiotics used in pig breeding and veterinary medicines as growth promoters and antibacterial drugs. The aim of this study was to examine the effects of these antibiotics and thermophilic pre-treatment on methane (CH4) yield by anaerobic co-digestion (AcoD) of pig manure and corn straw under mesophilic temperature condition (35 ± 1 °C). We used antibiotics at a concentration of 0, 20 and 60 mg L−1 (three stages) in two lab-scale continuously stirred tank reactors. The first reactor was run using untreated fed and the second reactor was run with thermophilic (55 ± 1 °C) pre-treated fed. The results showed that the CH4 productions from reactor one were 205, 163 and 128 and from reactor two were 222, 185 and 173 mL CH4 g−1 VSadded, respectively. This elucidates that the presence of antibiotics had a negative effect on CH4 production. Moreover, thermophilic pre-treatment improved the performance of the anaerobic digestion and CH4 production.