Deciphering impacts of sulfadiazine on anaerobic co-digestion of pig manure and food waste for methane production

In this study, the impact of sulfadiazine (SDZ) at environmental and elevated levels on the integrated anaerobic digestion of pig manure with food waste was explored. Results showed that SDZ concentrations ranging from 50 and 450 mg/kg of total solids inhibited methane production by 3.3 % to 50.8 %. Moreover, SDZ hindered the acidification and methanogenesis processes but had minimal impact on the hydrolysis phase. Mechanism studies revealed that extracellular polymeric substances (EPS) absorbed and accumulated SDZ via amine, hydroxyl, and carboxyl groups. Then, SDZ incited microorganisms to secrete high amounts of EPS and reactive oxygen species. These compounds inhibited enzyme activity, thereby disrupting the processes of acidification and methanogenesis. Furthermore, SDZ remarkably reduced the populations of acidogenic bacteria and methanogens, rendering the microbial community inhospitable to methane generation. This study offers a noteworthy reference regarding the response of the anaerobic co-digestion system to various concentrations of SDZ.