| Abstract |
| The purpose of this study was to find the optimal C/N ratio for sludge reduction and biogas production through a two-step anaerobic co-digestion process of acidogenically fermented maize stalk broth (AFMB) with sewage sludge. AFMB was prepared as follows: Crushed maize stalk were mixed with 20% (v/v) tap water. The mixture was put into a 10-L cylindrical reactor and anaerobically fermented at 100 rpm and 55 ± 2 °C without pH control (initial pH was 7.2 ± 0.3) to improve fermentation efficiency of maize stalks. The ratio of C/N was prepared to 5.32, 8.62, 12.27, 18.15, 24.43 and 30.75 using the mixing of AFMB and sewage sludge for sludge reduction and biogas production in the anaerobic co-digestion process. The highest total solid (TS) and volatile solid (VS) removal efficiency and biogas recovery was observed with C/N ratio of 18.15, which was found to be 58.13%, 67.85% and 1841.05 mL for TS, VS and biogas, respectively. Above C/N ratio of 24, the activation of microorganisms was inhibited by low pH, thereby TS, VS removal efficiency and biogas production were reduced. Therefore, in case of sludge reduction and biogas production in the anaerobic co-digestion process using AFMB, the optimum C/N ratio was recommended between 18-24. In addition, the production of biogas using AFMB in anaerobic co-digestion was determined a methane content of more than 70%, which opens the possibility of biogas production using AFMB. |
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| Key Words |
| Anaerobic codigestion, Biogas, Carbon and nitrogen ratio, Maize stalk acidogenic fermented broth, Sludge reduction, 혐기성병합공정, 바이오가스, 탄소질소비율, 옥수수대산발효액, 슬러지감량 |
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