Co-digestion of blackwater with kitchen organic waste: Effects of mixing ratios and insights into microbial community.

The current study was conducted to investigate the effects of mixing ratios on anaerobic co-digestion of blackwater and kitchen organic waste. The biological methane potential (BMP) of co-digested blackwater and kitchen waste were 0.85 ± 0.07 and 0.83 ± 0.06 at volatile solids (VS) ratios of 1:2 and 1:3 whereas the BMP of blackwater alone was 0.34 ± 0.01. The hydrolysis efficiency improved from 57 ± 8% in anaerobic digestion of blackwater alone to 87 ± 8% in the blackwater/kitchen waste co-digestion condition. The methane production yield increased from 449 ± 32 Nml CH 4 /gVS for blackwater only to 680 ± 58 and 630 ± 52 Nml CH 4 /gVS at blackwater/kitchen waste VS ratios of 1:2 to 1:3. Hydrogenotrophic methanogens dominated the methanogen community under a blackwater/kitchen waste VS ratio of 1:2 condition. The results suggest that blackwater energy recovery can be improved by co-digesting blackwater with kitchen waste. Image 1 • Blackwater/Kitchen waste at VS ratios of 1:2–1:3 achieved the highest performance. • Co-digestion led to hydrolysis efficiency increase of 53% and methane yield of 51%. • Co-digestion enriched for Clostridiaceae 1 and Anaerolineaceae. • Hydrogenotrophic methanogens dominant archaea community. [ABSTRACT FROM AUTHOR]