Effects of FeCl3 on anaerobic digestion of cyanobacterial biomass from Lake Chao, one of the most serious eutrophic freshwater lakes in China, were investigated. Results showed that FeCl3 was one feasible additive for the anaerobic process and methane generation rate and yield were both enhanced. The maximum methane yield reached 234 mL g(-1) based on the degraded volatile solid when the dosed FeCl3 was 0.25 g L-1, while the methane yield was only 131 mL g(-1) in the control reactor. Decomposition efficiency of cyanobacterial biomass and release of element P were promoted significantly (P < 0.05). (C) 2013 Elsevier Ltd. All rights reserved.