Bioresource Technology, Vol.276, 325-334, 2019
Co-production of biohydrogen and biomethane from food waste and paper waste via recirculated two-phase anaerobic digestion process: Bioenergy yields and metabolic distribution
To achieve the co-production of H-2 and CH4, co-digestion of food waste (FW) and paper waste (PW) was performed on the recirculated two-phase anaerobic digestion (R-TPAD). The PW content in the feedstock increased from 0% to 20%, 40% and 50% (in total solids) with FW as the rest. The results showed that bioH(2) and bioCH(4) were simultaneously and stably produced in the long-term operation. With the increasing PW content, the removal efficiency of volatile solids decreased slightly from 84.9% to 78.4%; the bioH(2) yields increased from 50 to 79 NL-H-2/kg-VSfed while the bioCH(4) yields decreased from 426 to 329 NL-CH4/kg-VSfed. With the fixed amount of FW, adding PW could significantly increase the total bioenergy yields. The relative abundance showed that the key H-2-producing bacteria, Caproiciproducens and Thermoanaerobacterium, increased after PW addition. The microbial distribution suggests that the H-2-producers were recirculated to the first stage after proliferating in the second stage.