INFLUENCE USING POTATO AS CO-SUBSTRATE ON ACIDIFICATION FERMENTATION AND BIOGAS YIELDS OF Spartina alterniflora

摘要

Influences of anaerobic co-digestion of Spartina alterniflora, a lignocellulosic biomass, with potato on acidification fermentation of S. alterniflora and its biogas yields 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 the acidification fermentation for co-digestion was butyrate type compared with that of propionate type for digestion of pure S. alterniflora, and the total VFAs concentrations for co-digestion increased more than two times compared with that of digestion of pure S. alterniflora. The concentration order of major individual VFAs produced in co-digestion was "acetate > propionate > butyrate", which was different from "butyrate > acetate > propionate" for digestion of potato and "propionate > acetate > butyrate" for digestion of S. alterniflora. The results also indicated that the co-digestion at S. alterniflora to potato ratio of 6:1 was optimal, with the biogas yield of 460 ml/g VS, an increase of 27.4% compared with 361 ml/g VS obtained in digestion of pure S. alterniflora. In addition, the average methane content of the biogas from co-digestion ranged between 60% and 63%, which was higher than that of 57% obtained in digestion of pure S. alterniflora. It was concluded that great changes of VFAs were obtained for co-digestion compared with digestion of pure substrate, and in general, these changes were beneficial to improve biogas yield and biogas quality ofS. alterniflora.