Biomass Energy and Environmental Engineering Research Center, Beijing University of Chemical Technology, Beijing, China.
Beijing No. 80 High School, Beijing, China.
Water Environ Res. 2021 Aug;93(8):1370-1380. doi: 10.1002/wer.1527. Epub 2021 Feb 14.
The effect of pH regulation in phase I on hydrolysis and acidogenesis rate, metabolites production, microbial community, and the overall energy recovery efficiency during two-phase anaerobic digestion (AD) of food waste (FW) was investigated. pH strongly affected the acidogenesis rate and the yield of the fermentation products. The highest acidogenesis efficiency (60.4%) and total volatile fatty acids (VFA)/ethanol concentration (12.4 g/L) were obtained at pH 8 during phase I. Microbial community analysis revealed that Clostridium IV was enriched at pH 8, relating to the accumulation of butyrate. Also, Clostridium sensu stricto played a crucial role in hydrogen production and was abundant at pH 6, resulting in the highest hydrogen yield (212.2 ml/g VS). In phase II, the highest cumulative methane yield (412.6 ml/g VS) was obtained at pH 8. By considering the hydrogen and methane production stages, the highest energy yield (22.8 kJ/g VS, corresponding to a 76.4% recovery efficiency) was generated at pH 8, which indicates that pH 8 was optimal for energy recovery during two-phase AD of FW. Overall, the results demonstrated the possibility of increasing the energy recovery from FW by regulating the pH in the hydrolysis/acidogenesis phase based on the two-phase AD system. PRACTITIONER POINTS: pH 8 was suitable for hydrolysis, acidogenesis, and methanogenesis. High hydrogen yields were obtained at pH 5-8 (about 200 ml/d). Clostridium sensu stricto might have played a crucial role in hydrogen production. High methane production (about 400 ml/g VS) was obtained at pH 7-9. pH 8 was optimal for energy recovery from FW with an efficiency of 76.4% (22.8 kJ/g VS).
研究了 pH 值调节对单相和两相厌氧消化（AD）过程中水解酸化速率、水解酸化产物、微生物群落以及整体能量回收效率的影响。pH 值强烈影响酸化速率和发酵产物的产率。在单相 AD 中，pH 值为 8 时，酸化效率（60.4%）和总挥发性脂肪酸（VFA）/乙醇浓度（12.4 g/L）最高。微生物群落分析表明，Clostridium IV 在 pH 8 时富集，与丁酸的积累有关。此外，Clostridium sensu stricto 在产氢过程中发挥着关键作用，在 pH 6 时丰度较高，产生的氢气产量（212.2 ml/g VS）最高。在两相 AD 的第二阶段，pH 8 时的累积甲烷产量（412.6 ml/g VS）最高。综合考虑氢气和甲烷的产生阶段，在 pH 8 时的能量产率（22.8 kJ/g VS，回收率为 76.4%）最高，表明在两相 AD 过程中，pH 8 有利于 FW 的能量回收。总的来说，结果表明通过调节两相 AD 系统水解/酸化阶段的 pH 值，FW 的能量回收可以提高。实际意义：pH 8 适合水解、酸化和产甲烷。在 pH 5-8 （约 200 ml/d）时可以获得较高的氢气产量。Clostridium sensu stricto 可能在产氢过程中发挥了关键作用。在 pH 7-9 时可获得较高的甲烷产量（约 400 ml/g VS）。pH 8 是 FW 能量回收的最佳条件，效率为 76.4%（22.8 kJ/g VS）。
