| 内容提要: |
In this study, a temperature-separated two-stage anaerobic fermentation process of waste activated sludge (WAS) and food waste (FW) was performed to optimize the sludge retention time of methane producing stage (M-SRT) and sludge return ratios of the system (SRR). Results show that higher M-SRT improved the removal of organics and energy yield of the system but reduced the stability of hydrogen production in H2-reactor. In this study, all the M-SRT conditions were below the threshold level. The highest total energy yield and volatile solid (VS) removal efficiency of the two-stage system of 8.98 kJ/g-VS and 63.8% was observed under the optimized M-SRT of 12 d. Return sludge could complement alkalinity for acidogenic stage especially with higher SRR, but the methanogens in it inhibited hydrogen production and caused stage transfer eventually. The optimized SRR was 1:1 with comprehensive consideration of energy yield, VS removal efficiency and alkali dosage. The dominant bacterial families in acidogenic stage were Ruminococcaceae and Clostridiaceae in this study. |