微量金属在餐厨垃圾厌氧消化中的应用研究
摘 要:餐厨垃圾经厌氧消化可产生沼气等可再生能源,但是餐厨垃圾常因微量金属元素缺乏导致反应器酸化,运行不稳定。投加微量金属元素能够促进产甲烷菌生长、提高关键酶的活性,加速挥发酸向甲烷的转化。因此,本文重点阐述微量金属元素在餐厨垃圾厌氧消化过程中的重要作用,以及产甲烷菌对微量金属元素的需求量。同时,本文还总结了微量金属元素单独、联合投加对餐厨垃圾厌氧消化的影响,分析了微量金属形态的变化及螯合剂对其生物利用度的研究进展,并归纳了该领域未来的研究方向。
关键词:餐厨垃圾;厌氧消化;微量金属元素;生物利用度
Application and Research of Trace Metal Elements in Anaerobic Digestion of Kitchen Wastes
ZHONG Ting-ting 160605229 Water Supply and Drainage Science and Engineering
Abstract: The renewable energy such as biogas can be produced from anaerobic digestion of kitchen wastes, but the reactor acidification and process instability often occurr due to the deficiency of trace metal elements in kithen wastes. The addition of trace metals can promote the growth of methanogens, increase the activity of key enzymes, and accelerate the conversion of volatile acids to methane. Therefore, the important roles of trace metals in anaerobic digestion, and the requirements of methanogens for trace metals are elaborated emphatically in this paper. Simutaneously, the effects of single and combined dosing on the anaerobic digestion of kitchen waste are summarized, and the changes of metal speciation and the research progress of chelating agents on their bioavailability are also analyzed. Simultenously, the future research directions in this field was summarizes.
Keywords: Kitchen waste; Anaerobic digestion; Trace metals elements; Bioavailability
随着经济发展和人口增长,我国每年产生的餐厨垃圾超过9000万吨[1-3]。尽管餐厨垃圾易腐败变质、滋生蚊蝇,但其中所含的碳水化合物、蛋白质、脂类和挥发性脂肪酸(VFAs),可通过厌氧消化转化为乙醇、氢气、甲烷和生物柴油等可再生能源[4-7]。然而,餐厨垃圾厌氧消化过程中,常因微量元素含量较低,造成反应器酸化,工艺运行不稳定等问题[7-10]。最近研究发现,投加微量金属元素能够加速底物降解,刺激厌氧微生物的生长,促进乙酸、丙酸等VFAs向甲烷的转化,进而提高反应器的处理负荷和稳定性,提高甲烷产率[8-11]。此外,微量金属元素还能在一定程度上消除氨氮对产甲烷过程的抑制,降低生物气中的H2S含量[12, 13]。值得注意的是,投加到厌氧反应器中的微量金属元素大多易形成沉淀,不能被微生物吸收,并作用于酶的活性中心[13-14]。最近的研究发现,微量金属元素与螯合剂的复合物一起投加能够提高微生物对微量金属元素的利用效率,减少投加量[12,14, 15]。
1. 微量金属元素在餐厨垃圾厌氧消化中的作用
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