LAUSR

Abstract 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 CH4/gVS for blackwater only to 680 ± 58 and 630 ± 52 Nml CH4/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.