零价铁耦合弱磁场强化含抗生素畜禽养殖废水厌氧消化的机理与应用基础研究

Anaerobic digestion (AD) is one of the most promising technologies for biowaste reclamation. Nevertheless, AD of livestock wastewater often encounters ammonia and antibiotic inhibition, resulting in decreased methanogenic activity. The antibiotic residues resulting from incomplete anaerobic degradation of the organic wastewater could also be a problem of concern during digestate application on arable land. Compared with acetoclastic methanogens (AM), hydrogenotrophic methanogens (HM) have a faster growing rate and a higher tolerance to toxicants. Based on this fact, the aim of the current study is to alleviate ammonia and antibiotic inhibition during AD of livestock manure, as well as to accelerate antibiotic degradation, by strengthening the hydrogenotrophic methanogenesis pathway using zero-valent iron coupled with weak magnetic field. The mechanisms of improved methane production will be elucidated, and the effect of iron dissolution on dynamic changes of bacterial population will be investigated by using various analytical methods. Moreover, the combined effect of zero-valent iron and weak magnetic field on tetracyclines degradation will be studied, and the key factors governing tetracyclines removal will be revealed. This study will not only contribute to a novel and workable strategy for improving AD of livestock wastewater, but also it will provide a new concept for anaerobic treatment of organic wastewater containing different toxic micropollutants (e.g. pesticides, polycyclic aromatic hydrocarbons, etc.).

厌氧消化是最具前景的生物质废弃物资源化技术之一。但畜禽养殖废水的厌氧消化过程易受氨和抗生素抑制，导致甲烷产率低下，且消化过程中抗生素降解不充分也将影响沼液的农田安全利用。针对以上问题，本项目根据厌氧体系中氢营养型产甲烷菌比乙酸营养型产甲烷菌世代周期短、对毒害物耐受性更高的特点，拟通过添加零价铁并耦合弱磁场的方式，强化氢营养型甲烷化途径并促进抗生素的降解。本课题将结合多种物理化学和生物分析手段，系统地研究零价铁缓解厌氧过程氨和抗生素抑制的作用机制和弱磁场的调控机理，揭示铁溶蚀对产甲烷功能种群分布规律的影响；并探明零价铁-弱磁场的结合对典型四环素类抗生素降解的促进机制，解析抗生素去除的关键驱动因子。本项目的开展不仅可为含抗生素畜禽养殖废水的资源化、无害化处理提供新的思路，还将对其它含有毒微污染物（如农药、多环芳烃等）有机废水的厌氧处理起到借鉴作用。

畜禽养殖废水的厌氧消化过程易受氨和抗生素抑制，导致甲烷产率低下。因此寻求有效途径缓解厌氧过程氨与抗生素胁迫，实现畜禽粪便的高效资源化利用与该过程中高风险抗生素的无害化是亟待解决的难题。项目根据氢营养型产甲烷菌比乙酸营养型产甲烷菌世代周期短、对毒害物（如氨氮与抗生素等）耐受性更高的特点，提出通过添加零价铁并耦合弱磁场的方式，强化氢营养型甲烷化途径并促进抗生素的降解。本项目重点研究了零价铁提升甲烷产率的机制和弱磁场的调控机理，从产甲烷功能菌群的组成结构和代谢活性角度，揭示了零价铁的溶蚀对厌氧产甲烷和抗生素降解的促进机理，并阐明了弱磁场对零价铁-微生物间电子转移的驱动机制。本项目的研究成果可为厌氧系统的高效稳定运行提供理论和技术基础。