基于原位近红外技术对猪场粪污高负荷厌氧消化过程中挥发酸、产甲烷菌及其主要代谢产物的实时在线检测研究

Anaerobic digestion, an effective way to utilize swine manure resources, can meet the needs of energy shortage and is an important part of energy structure in the future. The bottleneck problem is that the organic load of the biogas project is not high while the volume gas production rate is low, which leads to the poor economic performance of the project. However, under the high organic load, anaerobic digestion system is prone to acidify and destabilize. The key to break through the bottleneck lies in timely grasping the operation of the project, early warning of instability and stable regulation. At present, there is no real-time monitoring system for anaerobic fermentation using swine manure as raw material at home and abroad. In this project, near-infrared detection technology will be used to monitor the methanogenesis phase of anaerobic digestion process in real time. Near- infrared spectroscopy data of anaerobic digestion process will be collected quickly, at the same time, the characteristic bands will be selected by the multivariate curve resolution algorithm in chemometrics. The contents of volatile fatty acids in the substrate, the abundance of methanogens and the main metabolites of bacteria will be tabulated. In order to realize the effective monitoring of anaerobic digestion process, a simple and fast online monitoring system for anaerobic digestion process was established to realize the real-time monitoring and early warning of biogas engineering, and to provide support and help for the improvement of anaerobic digestion process engineering and technology of pig manure.

厌氧消化是猪场粪污资源化利用的有效手段，能补齐能源供需短板，是未来能源结构重要的组成部分。目前的瓶颈问题是生物天然气工程有机负荷不高，容积产气率较低，导致工程经济性欠佳。其主要原因之一是在高有机负荷条件下，厌氧消化系统易酸化失稳。突破该瓶颈的关键在于及时掌握工程运行情况，进行失稳预警和稳定调控。目前国内外尚未建立成熟的以猪粪为原料的厌氧发酵实时监控体系，无法做到实时监测。本项目拟采用近红外检测技术，对厌氧消化过程的产甲烷阶段实施实时监测，快速采集厌氧消化过程的近红外光谱数据，并结合化学计量学中的多元曲线分辨算法筛选特征波段，对底物中多种主要挥发性脂肪酸的含量、产甲烷菌丰度及菌种主要代谢产物含量进行表征，以实现对厌氧消化过程的有效监控，最终建立一套简便快捷的厌氧消化过程在线监测系统，实现对沼气工程的实时监控和预警，为猪粪的厌氧消化过程工程与工艺的改进提供支撑与帮助。

我国是农业大国，由养殖业和种植业产生的大量农业废弃物，是现代农业发展遇到的难题。目前，厌氧发酵手段是资源化利用生物质的重要手段。修建的生物天然气、沼气工程可通过厌氧发酵手段，把废弃物转化为清洁能源。近红外（NIR）光谱技术通过近红外光测得物质内部分子发生能级跃迁，引起波长在780~2526nm范围的含氢官能团出现振动、拉伸和结合，测得物质NIR光谱。将NIR光谱结合化学计量学算法可以建立快速预测模型，，具有速度快、预测精度高、无化学污染等特点，被许多领域广泛应用。本研究通过建立基于近红外的预测方法，对厌氧发酵体系中可溶性糖、挥发性脂肪酸进行预测。这项预测方法，可以为生物天然气、沼气工程的启动、运行提供便捷、高效的检测方法。与此同时，沼渣沼液的高效利用是解决农业面源污染的重要手段。目前，沼液利用受限于营养成分检测耗时的缺点。针对此，本研究针对水培用沼液建立起的快速检测方法，为沼液的还田利用提供了参考。为进一步比较厌氧发酵和燃烧对二氧化碳减排产生的影响，课题组基于近红外技术，建立农业废弃物碳排放估算策略。这些近红外方法的建立和完善，对农业废弃物资源化利用提供了更为经济、更为便捷的检测技术。