Abstract：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.
