玉米秸秆高浓度厌氧发酵的启动过程特性

Start-up process for high-solid anaerobic fermentation of corn straw

高浓度厌氧发酵具有单位体积产气率高、原料处理量大、需水量小、能耗低等优点,同时存在启动难和易酸化的问题。以玉米秸秆为原料,研究秸秆高浓度发酵过程接种物、分批进料结合渗滤液回流对启动的影响。结果表明,分批进料结合渗滤液回流工艺可有效实现高浓度厌氧发酵系统的稳定启动,反应器启动运行22 d,以污泥为接种物的秸秆累积产沼气量为43.54 ml·(g TS)?1,以湿法发酵的沼液为接种物的秸秆累积产沼气量为115.15ml·(g TS)?1。与以厌氧污泥为接种物的发酵系统相比,以湿式发酵沼液为接种物的高浓度厌氧发酵系统秸秆微观结构变化更明显,主要表现为半纤维的溶解;荧光原位杂交技术(FISH)结果也表明两种接种物系统的甲烷菌形态存在明显差异。

High-solid anaerobic fermentation has the advantages, such as higher biogas yield per unit volume, more organic waste disposal, smaller water requirement and less energy consumption. However, the reactor is difficult to start and easy to acidize due to high concentration of feedstock. Using corn stalk as substrate, the performance of start-up process, different inocula and slurry recycling methods were studied during the start-up process for high solid anaerobic fermentation. The reactor system remained stable during the start-up phase with the combined method of feedstock feeding and slurry recycling. The cumulative biogas yields were 43.54 ml·（g TS）-1 with sludge as inoculum and 115.15 ml·（g TS）-1 with corn straw wet fermentation slurry as inoculum in 22 days. X-Ray diffraction （XRD） showed that the CrI was strongly influenced by the microflora, which showed that semicellulose was mainly dissolved. Fluorescentin situ hybridization （FISH） demonstrated that the methanogenic archaea exhibited an obvious difference in the two methane fermentation systems inoculated with sludge and corn straw biogas slurry, respectively.