油脂含量和电发酵电压对含油餐厨垃圾厌氧消化产甲烷的影响

INFLUENCE OF LIPID CONTENT AND ELECTRIC FERMENTATION VOLTAGE ON METHANE PRODUCTION FROM FOOD WASTE ANAEROBIC DIGESTION

现有餐厨垃圾处理过程中存在油脂包裹厌氧消化菌群的状况,经提油后,仍有大量油脂进入发酵体系,对发酵稳定性造成一定危害。为缓解此问题,研究了通电预处理对于含油餐厨的厌氧消化促进作用。采用0.8 V电预处理的含油(50%)餐厨垃圾甲烷产率,较未处理组,由(780.43±4.49)mL/g TVS提升了6.5%,达到(831.06±13.85)mL/g TVS。而最高产甲烷速率由(35.84±0.64)mL/(g TVS·d)提升了20.3%,达到(43.11±0.72)mL/(g TVS·d)。达到峰值速率的时间由20 d大幅缩减至14 d。研究表明,在一定的外加油脂添加范围(0~50%)内,随着油脂含量的提升,电预处理对于厌氧消化的促进作用越强。微观图像表明,在0.8 V电压下,电极表面附着大量微生物,而未处理组无可见微生物附着。根据三维荧光光谱测试结果,0.8 V电压下微生物对于腐殖酸等代谢底物的利用明显提升。电压对于含油餐厨垃圾的厌氧消化促进作用可能从3个方面进行解释:加强微生物与电极的接触,促进油脂的酸化降解,提高乙酸化和甲烷化途径的电子传递。

At present,in the process of food waste treatment,the situation that anaerobic digestion microorganisms coated by lipids often occurs.After lipids extraction,a large amount of lipids still enters the digestion system,which causes certain harm to the stability of the system.To alleviate this problem,the promoting effect of electric pretreatment on anaerobic digestion of high lipid content food waste was studied in this research.Compared with the untreated group,the methane yield of food waste(50%of lipids)treated with 0.8 V increased by 6.5%from(780.43±4.49)mL/g TVS to(831.06±13.85)mL/g TVS.The peak methane production rate increased by 20.3%,from(35.84±0.64)mL/(g TVS·d)to(43.11±0.72)mL/(g TVS·d).The time to reach the peak rate was reduced from 20 days to 14 days.The results showed that in a certain range of added lipids(0 to 50%),with the increase of lipids content,electric pretreatment demonstrated a better promoting effect on anaerobic digestion.Microscopic images showed that a large number of microorganisms were attached to the electrode surface at a voltage of 0.8 V,while no microorganisms were observed in the untreated group.According to the results of the three-dimensional fluorescence spectrum test,utilization of metabolic substrates such as humic acid was significantly improved at a voltage of 0.8 V.The promoting effect of voltage on the anaerobic digestion of high lipid content food waste can be explained from three aspects:enhancing the contact between microorganisms and electrodes,promoting the acidification and degradation of lipids,and improving the electron transfer through acetoxylation and methanation pathways.