生物强化菌系添加量对不同食微比餐厨垃圾厌氧发酵性能影响

Effect of Bioaugmentation on Anaerobic Digestion of Food Waste at Different Food to Micro Ratios

为考察生物强化菌系添加剂量对餐厨垃圾厌氧发酵性能影响,确定不同食微比(F/M)下最佳菌剂添加量,进行了批式厌氧发酵实验。以实验室已获得的丙酸产甲烷菌系为生物强化菌系,对不同F/M(0.5、1.0、2.0)进行生物强化,菌剂添加量设置为5%、10%、15%、25%、35%比,通过产气性能及中间代谢产物的对比,结合产甲烷动力学评价生物强化效果。结果表明:各剂量的生物强化均可促进餐厨垃圾产气,提高累积产甲烷率1~3倍;各F/M下,累积产甲烷率均随生物强化剂量增加而增大,35%的添加量产气效果最佳。就生物强化效率而言,3组F/M发酵中,F/M为1.0且菌系添加量为15%时,单位质量菌剂获得最大甲烷提升效率(1706 mL/gVS_(菌剂));中间代谢产物分析显示,生物强化可促进丙酸和乙酸的降解,避免酸抑制,从而提高产甲烷能力。修正Gompertz模型对产甲烷潜力动力学分析表明,生物强化可以缩短不同食微比下的发酵延滞期,加快反应进程。

This study aimed to investigate effect of bioaugmentation on anaerobic digestion of food waste and achieve optimum dosage of bioaugmentation inoculum under various of ratios of VS from the inoculum and VS of the substrate(ISR).Thus,methanogenic propionate-utilizing consortia,as the bioaugmentation inoculum,were introduced into batch anaerobic digestion reactors with different ISR(i.e.,0.5,1.0,and 2.0),and the dosages of inoculum was set at 0%,5%,10%,15%,25%,and 35%(on the basis of VS),respectively.This study showed that bioaugmentation across all groups had varying degrees of positive effect on methane production rate,ranging from 1 to 3 times higher.Inoculum dosage showed the positive correlation with cumulative methane production rate,and groups with the dosage of 35%showed the best performance,which was applied to all groups with different ISR.Besides,amongst all groups,the group with inoculum dosage of 15%and ISR of 1 achieved the highest bioaugmentation efficiency of 1706 mL/g VS_((bioaugmentation inoculum)).As evidenced by intermediate metabolites analysis,the addition of bioaugmentation inoculum significantly alleviated acid inhibition through accelerating biodegradation process of derived propionic acid and acetic acid and then recovered methane yields from acid inhibition.Focusing on kinetics of methane production by modified Gompertz model,the results indicated that the addition of bioaugmentation inoculum could shorten the lag phase and accelerate anaerobic digestion process across groups with different ISR.