기질 혼합비와 식종원 특성이 하수슬러지와 음식물류폐기물의 혐기성 소화에 미치는 영향 평가

초록

We evaluated the effects of feedstock mixing ratios and inoculum sources on the anaerobic digestion of sewage sludge (SL) and food waste (FW) through batch experiments and methanogen community analysis. Both factors influenced methane yield and production rate significantly (p < 0.05). The feedstock mixture ratio had a greater contribution to methane yield variation, and both feedstock mixture ratio and inoculum source affected methane production rates substantially. Co-digestion showed increasing methane yield with higher FW proportions, reaching levels similar to food waste alone at an SL:FW ratio of 25:75 in chemical oxygen demand (COD; 293 ± 11 mL CH4/g COD). Ob served methane yields were 13–19% higher than theoretical weighted means, indicating a synergistic co-digestion effect. Methane production rates also increased at ratios of 50:50 and 25:75, reaching values 74–97% higher than sludge alone. Inoculum type strongly affected variability, with co-dige ster-derived inocula yielding the highest activity and stability. Sequencing demonstrated that these inocula harbored balanced populations of acetoclastic (Methanothrix), hydrogenotrophic (Methano linea, Methanospirillum), and methylotrophic (Methanofastidiosales) methanogens, enabling robust conversion of diverse intermediates. These results indicate that co-digestion-derived inoculum, com bined with FW proportions of >50–75%, may help improve start-up stability and optimize methane productivity in full-scale SL–FW co-digestion systems.

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