乙醇预发酵对餐厨垃圾与酒糟水解酸化和甲烷发酵的影响

Effect of ethanol pre-treatment on hydrolytic acidification and methane fermentation of food waste and distillers'grains

为了解决餐厨垃圾与酒糟干式甲烷发酵过程易酸化问题,考察了两种乙醇预发酵方式-餐厨垃圾单独预发酵和餐厨垃圾与酒糟混合预发酵对底物水解酸化和甲烷发酵的影响,并与不进行乙醇预发酵的对照组比较.结果显示,对照组、餐厨垃圾单独预发酵组(简称"FW预发酵组")、餐厨垃圾与酒糟混合预发酵组(简称"FW+DG预发酵组")的甲烷总产率分别为22.8,222.4,231.3m L/g VS.乙醇预发酵可以促进发酵底物的水解,预发酵结束后,FW预发酵组发酵底物中的乙醇、总挥发性脂肪酸(TVFA)、乙酸浓度与对照组相比分别提高了4.5、1.4、4.9倍,FW+DG预发酵组则分别提高了7.8、1.6、5.9倍.另外,在甲烷发酵过程中,预发酵组的乙醇浓度显著高于对照组,而乙酸、丙酸和TVFA浓度明显低于对照组,表明乙醇预发酵使有机物更多的转化为乙醇,减少了有机酸的生成,有效缓解甲烷发酵过程中的酸积累、产甲烷受抑制等问题.

To prevent the anaerobic co-digestion of food waste （FW） and distillers＇ grains （DG） system from acidification, the performance of anaerobic digestion of FW and DG with different ethanol pre-treatment （EP） methods （i.e., FW EP and FW＋DG co-EP） was evaluated. The results showed that the cumulative methane yield of control （i.e., without EP）, FW EP and FW＋DG co-EP groups were 22.8, 222.4, 231.3mL/g-VS, respectively. The ethanol, TVFA and acetic acid content of the hydrolysates in FW EP group were 4.5, 1.4 and 4.9 times higher than those in the control group, while 7.8, 1.6, 5.9 times higher in FW＋DG co-EP group. It indicated that EP could promote the hydrolysis extent and methane yield of the substrates. Moreover, the ethanol content of the EP groups were markedly higher than that in the control group, but acetic acid, propionic acid and TVFA content were remarkably lower than those in the control group. The results suggested that organic matter of the substrates tends to convert into ethanol, instead of VFAs, in EP scenario. Thus, EP is an effective way to prevent the accumulation of organic acids in anaerobic digestion systems.