Inhibitory Effect of Streptomycin on Methane Production of Anaerobic Granular Sludge

The inhibitory effect of streptomycin on methane production of anaerobic granular sludge treating starch wastewater was investigated. The results indicated that the methane production of anaerobic granular sludge was influenced in the presence of streptomycin ranged from 0 to120 mg/L. The larger final methane production, the less remaining COD and the higher final pH value at the end of tests were obtained at streptomycin concentration range varying from 5 mg/L to 40 mg/L, compared with these in control batches or at other higher streptomycin concentrations, indicating that the methane production depended on the multiple inhibitory effects of streptomycin on both acetogenic bacteria and methanogens being responsible for bioconversion of organic matter to methane. On the other hand, the inhibitory effect of streptomycin on methanogenesis seemed predominant in the initial 24 h. The initial methane production rates decreased with an increase in streptomycin concentration, which was simulated using Logistic model. The low half inhibitory concentration of streptomycin for methane production was obtained as 2.054 mg/L, indicating relatively strong inhibitory effect of streptomycin on methanogenesis of anaerobic granular sludge under this study conditions.