高温甲烷发酵过程的丙酸过量积累机制及调控技术研究

Due to the accumulation of propionic acid in thermophilic methane fermentation, stable performance and efficient energy recovery is hard to be achieved. In this project, the mechanism of propionic acid accumulation in thermophilic methane fermentation and technologies for process control will be systematically studied with the entry point of the phenomenon and driving factors analysis. Batch test combined with continuous pilot experiment will be employed for the mechanism studies of propionic acid accumulation associated with chemical, microbiological and molecular biological analysis. The dynamic mechanism of propionic acid production in hydrolysis and acidogenesis will be confirmed by bio-ecological environment condition analysis. The role of environmental factors and interspecies electron transfer will be investigated to identify the pathway and biochemical principle of propionic acid conversion. The multiple technologies for process control of thermophilic methane fermentation will be established based on the study of accumulation control and degradation enhancement of propionic acid. It will provide theoretical and technical foundation for optimizing the design of thermophilic digester and achieving stable performance with high efficient energy recovery.

针对高温甲烷发酵过程丙酸易积累、难降解，影响系统稳定运行，制约高效能源回收的问题，本项目拟从丙酸积累现象考察及其驱动因子识别为切入点，研究丙酸过量积累机制及调控技术。结合批次实验和连续中试实验，开展化学、微生物学、分子生物学分析和理论解析，深入研究水解酸化阶段的生物生态条件，判明丙酸产生的动力学机制；分析丙酸的乙酸化环境条件及种间电子传递作用，揭示其转化路径及生化原理；研究丙酸积累控制和降解促进途径，确立高温厌氧发酵过程调控的多元耦合技术策略。研究成果将为高温发酵系统优化设计和高效稳定运行提供理论和技术基础。

有机废弃物甲烷发酵系统在高负荷条件下极易发生丙酸等挥发性脂肪酸（VFAs）的过量积累，从而导致甲烷产率降低，甚至系统崩溃。研究以餐厨垃圾和剩余污泥为共发酵基质，从VFAs积累现象考察及其驱动因子识别为切入点，研究了VFAs过量积累机制及调控技术。通过批次实验与连续实验相结合的方式，在对不同基质组分的VFAs产生特性及VFAs降解动力学分析的基础上，以强化高负荷条件下高效稳定产甲烷为目标，具体解析了温度、进料频率及生物炭投加对发酵系统效能的影响，并从微生物的VFAs代谢活性及群落变化规律等方面进一步阐明了各种调控措施的潜在促进机理。重点研究了生物炭投加对传统VFAs互营产甲烷过程电子传递路径的影响，提出了以木质纤维素类废弃物热解强化餐厨垃圾与污泥高效稳定能源回收的耦合技术。