Table 2. Influence C/N ratio on ultimate biodegradability and volatile solids removal during anaerobic digestion at 18 d

Carbon type C/N ratio Ultimate biodegradability (%) Volatile solid removal (%) Biodegradable volatile solids removal (%)
Starch 10 100.0 82.7 82.7
25 99.2 86.4 87.1
40 99.5 89.3 89.8
Cellulose 10 99.5 88.3 88.3
25 99.5 91.9 92.3
40 99.5 95.4 95.9
Xylan 10 93.7 79.3 84.7
25 99.7 84.1 84.3
40 99.9 85.5 85.6
SEM 0.44 1.19 1.11
p-value1) C 0.001 <0.001 <0.001
CN <0.001 <0.001 <0.001
C × CN <0.001 0.935 0.048
C, effect of carbon type; CN, effect of carbon: nitrogen ratio; C × CN, interaction between carbon type and carbon: nitrogen ratio.
C/N ratio, carbon to nitrogen ratio; SEM, standard error of means.