Characteristics of acidification fermentation and biogas production for co-digestion of Spartina alterniflora and potato

Abstract

Influences of anaerobic co-digestion of Spartina alterniflora, a lignocellulosic material, and potato on acidification fermentation of S. alterniflora and its biogas production were investigated by anaerobic batch digestion experiments conducted at S. alterniflora to potato ratio of 6:1, 7:1 and 9:1 at 35°C. The results indicated that acidification fermentation for co-digestions was butyrate type compared with that of propionate type for mono-digestion of pure S. alterniflora, and the total volatile fatty acids (TVFA) concentrations for co-digestion increased more than twice compared with that of mono-digestion of pure S. alterniflora. The results also indicated that the cumulative biogas yields for co-digestion at SC:P ratios of 6:1, 7:1 and 9:1, respectively amounted to 460, 431 and 415 mL/g VS, increased by 27.4%, 19.3% and 15.0% than the 361 mL/g VS obtained in mono-digestion of pure S. alterniflora. In addition, the average methane contents of biogas produced in co-digestion at SC:P ratios of 6:1, 7:1 and 9:1 were 60.3%, 62.4% and 62.7%, respectively, about 3%-5% higher than 57.4% in mono-digestion of pure S. alterniflora. It was concluded that great changes of VFAs were obtained for co-digestion compared with mono-digestion of pure S. alterniflora, and in general, these changes were beneficial to improve biogas production and biogas quality of S. alterniflora digestion.