Hormesis of lanthanum and cerium on methanogenesis of anaerobic granular sludge and its kinetics
镧、铈对厌氧颗粒污泥产甲烷的Hormesis效应及其动力学研究

Batch experiments were conducted to investigate the effects of the rare earth ions La3+ and Ce3+ on the activity of anaerobic granular sludge and the kinetics of anaerobic digestion. The results showed that both of the ions can promote the Specific Methanogenic Activity (SMA) at concentrations from 0.01 to 0.1 mg·L-1 with a maximum promotion of 10.35% for La3+ and 20.79% for Ce3+. The EC50 concentrations were 5 mg·L-1 for La3+ and 1000 mg·L-1 for Ce3+, so La3+ is a stronger suppressant. The Michaelis-Menten model could be used to describe the kinetic behavior of the methane fermentation phase in anaerobic digestion. Addition of La3+ and Ce3+ increased the kinetic constants Vmax and Ks.