关键词:

餐厨垃圾')">"> 餐厨垃圾, 厌氧发酵, 酸化, 恢复, 预警参数

Abstract:

Anaerobic digestion (AD) for biogas production is currently the predominant treatment technology for food waste. However, improper operation can readily induce acidification. This study investigated the characteristics of acidification in food waste anaerobic digestion triggered by variations in organic loading rate (OLR), identified early-warning indicators for acidification, and evaluated the effectiveness of the "OLR reduction + Na?CO? supplementation" strategy for acidification mitigation and process recovery. Changes in digestion performance during these phases were comprehensively analyzed.The results demonstrate that increasing the OLR by 31.3% within 15 d induced system acidification. Significant precursors to acidification were observed in specific parameters: the specific biogas production (SBP), total alkalinity (ALK), volatile fatty acids (VFA), and the VFA/ALK ratio exhibited abnormal deviations 42 d, 40 d, 28 d, and 28 d, respectively, prior to the onset of acute acidification. These parameters thus serve as effective early-warning indicators, with SBP exhibiting the highest sensitivity. An early-warning protocol should be initiated when these parameters deviate from their stable operational ranges.During acidification, critical parameters reached their extremes: SBP, ALK, methane (CH?) content, and pH decreased to 520.4 m3/tVS/d, 7400 mg/L, 49%, and 6.98, respectively, representing declines of 66%, 27%, 19%, and 10.5% from initial baseline values. Conversely, VFA and VFA/ALK peaked at 5960 mg/L and 0.8, reflecting increases of 674% and 952%, respectively.Acidification was gradually reversed through the combined strategy of reducing OLR and supplementing Na?CO?. The entire cycle, from OLR-induced acidification to complete recovery, spanned 86 d. During this period, the feed load was reduced for 33 consecutive days, consuming 4,320kg of soda ash, demonstrating high feasibility and cost-effectiveness.Recovery dynamics revealed a sequential restoration of parameters: CH? content improved first, followed by SBP, pH, VFA, VFA/ALK, and finally ALK. Acidification was confirmed to be resolved, and the early-warning status lifted, once VFA and VFA/ALK stabilized below thresholds of 2000 mg/L and 0.25, respectively, establishing these as robust indicators for recovery monitoring.Statistical analysis confirmed significant correlations (p<0.01) among all monitored parameters throughout the stable operation, acidification, and recovery phases. This study provides valuable insights for implementing early-warning systems and recovery protocols for acidification in full-scale food waste anaerobic digestion plants, aiding operational management in practical engineering applications.

Key words:

food waste')">"> food waste, anaerobic , fermentation, acidification, recovery, Warning parameters