Effect of nickel on methane production and butyric acid utilization in a downflow fixed-film reactor

Abstract

Butyric acid conversion by a mixed methanogenic population in a pilot scale anaerobic downflow fixed-film reactor (DFFR), treating a cheese factory effluent was increased by the addition of nickel (30 mg/l NiCl2. 6H2O). The butyric acid concentration dropped abruptly (2300 to 150 mg/l) when the reactor was fed with Ni (II). Furthermore, when running two lab. scale DFFRs butyric acid utilization and methane production were slightly higher within the reactor supplemented with nickel than in the control reactor (without nickel).