腐殖质对污泥厌氧消化的影响及其屏蔽方法

《巴黎气候协定》的签署意味着污水处理碳中和运行时代的来临,这就需要将剩余污泥尽可能最大程度地转化为可再生能源—甲烷(CH4).细胞破壁、木质纤维素破稳及腐殖质解抑制是提高污泥厌氧消化能源转化率的主要技术手段.相对于细胞与木质纤维素,腐殖质不仅结构更为复杂、自身难以生物降解,而且还会抑制其它有机物水解.虽然腐殖质亦有促进酸化、产氢/乙酸、产甲烷过程的微弱可能,但它对水解过程的抑制是肯定的、显著的、难以逆转的.因此,需要深入了解污泥中腐殖质来源、形成、结构及性质,综合分析它对污泥厌氧消化水解、酸化、产氢/乙酸、产甲烷阶段的各种影响,探讨消除腐殖质抑制水解过程的不同技术路径,重点描述外加金属离子对腐殖质的屏蔽作用.以期为提高污泥厌氧消化能源转化率制定可行的技术路线.

Effects of humic substances on anaerobic digestion of excess sludge and their blocked approaches

Signing "the Paris Climate Agreement" means the immediate start of carbon-neutral operation of wastewater treatment, which needs to maximally convert excess sludge into renewable energy, methane (CH₄). Breaking both bacterial cells and lignocellulosic structures as well as eliminating inhibition effect of humic substances on hydrolysis are considered as major technical approaches to increase energy conversion from anaerobic digestion of excess sludge. Relatively to bacterial cells and lignocellulosic materials, humic substances are more complicated in structures, retardant in biodegradation, and even inhibiting to hydrolysis for other organic substances during anaerobic digestion. Although humic substances are possibly beneficial on acidification, syntrophic acetogenesis and even methanogenesis, they definitely inhibit hydrolysis, which is remarkable and irreversible. For this reason, it is essential to understand the source, formation, structure, and properties of humic substances, to analyze the effects of humic substances on hydrolysis, acidification, syntrophic acetogenesis and methanogenesis, to explore technical routes of relieving hydrolysis, and especially to focus the shield of humic substances by heavy metals. The aim of the review is to make possible technical routes to increasing energy conversion of anaerobic digestion for excess sludge.