| Title |
Evaluating Process Performance and Stability of Anaerobic Co-digestion of Food Waste and Sewage Sludge Infull-scale Anaerobic Sequencing Batch Reactor (ASBR) |
| Authors |
김세영(Se Yeong Kim) ; 양현명(Hyeon Myeong Yang) ; 최영환(Young Hwan Choi) ; 권진홍(Jin Hing Kwon) ; 전항배(Hang Bae Jun) |
| DOI |
https://doi.org/10.15681/KSWE.2025.41.6.549 |
| Keywords |
Anaerobic digestion; ASBR; Food waste; Microbial community; Sewage sludge |
| Abstract |
This study assessed the performance and stability of an anaerobic sequencing batch reactor (ASBR) that processes food waste and sewage sludge through integrated anaerobic digestion. The physical stability was evaluated by monitoring temperature variations and water level changes during intermittent mixing operations. The temperature differences between the upper and lower sections remained stable, within 0.3±0.2 °C, while water levels exhibited consistent variations of 0.4 m, indicating effective mixing without scum formation or dead zones. Biological stability was analyzed through microbial community assessments under various stress conditions. Ammonia inhibition experiments (4 g/L addition) led to volatile fatty acids (VFAs) accumulating beyond 10 g/L and significant shifts in methanogenic communities. Acetoclastic methanogens (Methanosarcina and Methanosaeta) decreased markedly, while hydrogenotrophic methanogens (Methanoculleus and Methanobacterium) increased to help maintain system stability. Variations in organic loading rates from 3.3 to 6.6 kgVS/m³·d elicited sensitive responses from Methanosarcina populations, highlighting the vulnerability of acetoclastic pathways to operational stress. Performance evaluations across differing hydraulic retention times (HRTs of 95.4 to 31.5 days) showed an increase in biogas production (330 to 1,975 m³/d) and methane yield (0.291 to 0.509 m³CH₄/kgVS) as HRT decreased. The anaerobic biodegradability reached 79.3%, consistent with previous studies. Stability assessments using alkalinity fractions (IA/TA, IA/PA) proved to be more sensitive indicators than conventional VFAs/alkalinity ratios. Additionally, the correlation between alkalinity fractions and archaeal community structure indicated that the proportion of hydrogenotrophic methanogens increased with intermediate alkalinity, emphasizing their vital role in maintaining system stability under stress conditions. |