有机负荷对酒糟厌氧消化降解及甲烷产率的影响

为了探究有机负荷对酒糟中温厌氧消化运行的稳定性及产气性能的影响，启动了有机负荷分别为1.6、4.8和6.4 kg·（m3·d）-1的厌氧反应器R1、R2和R3，并以半连续方式运行100 d。单因素方差分析（ANOVA）的结果表明，3个反应器在60~90 d的VS降解率无显著性差异（p=0.19>0.05），分别为（66.9±3.2）%、（68.1±2.7）%和（66.1±1.5）%，但产气率随着有机负荷的提高而升高，分别为（0.48±0.07）、（0.61±0.06）、（0.71±0.06）m3·kg-1，对应的甲烷比例为56.9%、60.9%和59.6%。虽然提高有机负荷促进了有机碳源利用效率，提高了甲烷比例和产量，但其稳定运行存在一定困难，R3在90 d后产气急剧下降，丙酸大量积累，产酸菌和产甲烷菌间的动态平衡受到破坏。因而，适宜的有机负荷是确保酒糟良好的厌氧消化稳定性能和产气性能的关键因素。

Effect of organic loading rate on volatile solids reduction and methane production in anaerobic digestion of distillers grains

To assess the effect of the organic loading rate (OLR) on the system stability and the biogas yield in the anaerobic digestion of distillers grains under mesophilic conditions, three semi-continuous reactors, R1, R2, and R3, were operated for 100 days with OLR values of 1.6, 4.8, and 6.4 kg·(m3·d)-1, respectively. During 60 to 90 d, the volatile solids reductions of the three reactors were (66.9±3.2)%, (68.1±2.7)%, and (66.1±1.5)%, respectively, showing no significant differences (ANOVA, p=0.19>0.05) among them. The corresponding biogas yields were (0.48±0.07), (0.61±0.06), and (0.71±0.06)m3·kg-1, and the methane proportions were 56.9%, 60.9%, and 59.6%. The elevated OLR did promote the carbon conversion efficiency for the methane yield. However, there were still difficulties in achieving stable operation with an OLR of 6.4 kg·(m3·d)-1. From 90 d, the R3 showed a sharp decline in biogas yield, and propionic acid accumulation occurred, which probably resulted from the imbalance between the acid-producing bacteria and the methanogens. Therefore, an optimal organic loading rate is one of the main factors to ensure the good performance of anaerobic digesters with distillers grains.