湿热预处理对餐厨废弃物厌氧产氢发酵类型的影响

Impact of Kitchen Waste Hydrothermal Pre-treatment on Anaerobic Fermentation Type and Hydrogen Production

通过批试验分析湿热预处理前后餐厨废弃物CODs(溶解性化学需氧量)、CODt(总化学需氧量)、粗蛋白浓度、碳氮比(C/N)等指标及代谢产物的变化,研究湿热预处理对餐厨废弃物厌氧发酵类型和产氢效能的影响。采用Gompertz动力学模型分析经湿热预处理后厌氧发酵系统启动速度、累积产氢量、产氢速率的变化。结果表明,餐厨废弃物经150℃湿热预处理30 min后,可浮油脱出量高达97.5 mL/kg,CODs和C/N变化显著;VFAs(挥发性有机酸)和乙醇浓度分析表明,湿热预处理可使餐厨废弃物厌氧发酵产氢的产酸类型从丙酸型发酵转变为丁酸型发酵。在微生物的作用下,湿热预处理时间为30 min时,经90℃处理后餐厨废弃物中的丁酸等VFAs进一步降解转化为乙酸、CO2和H2,比产氢量最高为242.1 mL/g(以VSS计)。湿热预处理可以改变餐厨废弃物中碳水化合物、蛋白质和脂肪的理化性质,影响其厌氧发酵产氢产酸类型,达到改善餐厨废弃物厌氧发酵产氢效能的目的。

Batch tests were carried out to analyze the influences of hydrotherrnal pre-treatment on anaerobic fermentation type and hydrogen production by measuring the variation of soluble chemical oxygen demand （CODs） , total chemical oxygen demand （ CODt ）, crude protein content, C/N and metabolites. Using Gompertz kinetics model, the change of anaerobic fermentation system boot speed, cumulative hydrogen production and hydrogen production rate caused by hydrothermal pre-treatment were studied. The result showed that floatable oil could be affected by hydrothermal pre-treatment which obtained a maximum yield of 97.5 mL/kg, and then the content of CODs and C/N changed significantly. The analysis of VFAs and ethanol concentration proved that hydrothermal pre- treatment can change the kitchen waste anaerobic metabolic pathways of hydrogen production from mainly propionic acid into butyric acid metabolic pathways. The 90℃-30 min pre-treatment which got a highest degree of specific hydrogen production yield at 242.1 mL/g（VSS） could shift the butyric acid into acetic acid and hydrogen by the effect of microorganism. The hydrotbermal pre-treatment could affect the characteristic of carbohydrates, proteinand fat in kitchen waste, thereby affecting hydrogen and acid production by anaerobic fermentation type of kitchen waste to achieve the purposes of enhancing the efficiency of hydrogen production performance by kitchen waste anaerobic hydrogen production.