Ammonia nitrogen(NH3-N) content was examined using thespectrophotometer (HACH, DR/2500). The compositionof methane in the biogas produced was analyzed using agas chromatography equipped with a thermal conductivity
detector (TCD). The column used was a HP Molesieve30m × 0.53mm × 0.05mm capillary column. The injector,oven and detector temperatures were set at 150oC, 60oCand 200°C, respectively. Argon served as the carrier gaswhile nitrogen was used as the makeup gas.