Abstract: With the progress of domestic waste classification and resource recovery in China, acidogenic fermentation of kitchen waste for resource utilization is confronted with problems such as low efficiency and difficulties in the utilization of fermentation liquid. The synergistic effect of mixed bacterial strains was utilized to enhance the acid production efficiency of kitchen waste fermentation and evaluate the possibility of resource utilization of the fermentation liquid as a carbon source for denitrification. With volatile fatty acids (VFAs) yield and chemical oxygen demand (COD) concentration as vital indicators, the impacts of microbial strain ratios and initial pH of kitchen waste slurry on acidogenic fermentation performance of kitchen waste were assessed. Results showed that with yeast, Acetobacter, Bacillus licheniformis, and Bacillus subtilis being co-inoculated at a ratio of 1.0∶0.5∶3.0∶4.5,under 30 ℃ with an initial pH of 8 for the kitchen waste slurry, peak VFAs concentration showed a 284.5% increase relative to the control group, whereas the biochemical-to-chemical oxygen demand (B/C) raised from 0.54 to 0.92. It indicated that the mixed bacterial strain significantly enhance the hydrolysis and acidification rate of macromolecular organic substances. Denitrification assays further verified that the denitrification performance of the composting liquid from kitchen waste was basically the same as that of industrial glucose, which proved that the composting liquid from kitchen waste enhanced by the mixed microbial agent is an economical, efficient and stable alternative carbon source.

Key words: microbial synergy, kitchen waste, anaerobic fermentation, VFAs, denitrification