The approximate volume of 28.75 kg slurry is 28.75 liters. Usually maximum volume of the slurry in the digester is about 80% to that of the total volume of the digester. This gives the total volume of the digester as 28.75/0.8=35.9 liters. But, this study also used poultry waste as fermentable material. Therefore, provision is made in the total volume of the chamber for that also. Considering the poultry waste whose gas production yield is 0.07 m3/kg and TS is 25%, the total volume of the slurry for 13.5 kg becomes about 42 liters. For slurry volume 80% of total volume, the total volume of the digester becomes about 52 liters. There is an optimum relation between the diameter D of the digester and the total volume Vas D=1.3078V1/3, where f1/D=1/5, f2/D=1/8 and H=D/2.5 [2]. This gives D=0.49 m, H=0.19m, f1=0.1 m and f2=0.06 m. The chamber dimensions are shown in Fig. 2.
Figure