Management of reoccurring process disturbances in agricultural digesters through post digestion, total solid adjustment and recirculation

The aim of this study was to elucidate mechanisms underlying perturbation of agricultural waste (AW) digesters by assessing the process response to operational remedies in relation to microbial community dynamics. Two serial continuously stirred tank reactors, namely as main digester (MD) and post digester (PD), simulating the operation of an existing full-scale biogas plant experienced process perturbations, in forms of declined biogas production, pH variations and accumulation of intermediate degradation products. To remedy this, different operational remedies were evaluated including, alternation of feeding intervals, recirculation of the liquid, and whole digestate. Recirculating part of digestate from PD stream to the MD resulted an increased in overall process stability.

本研究旨在阐明农业废弃物（Agricultural Waste, AW）厌氧消化器受工艺扰动的内在机制，通过评估运维调控措施的工艺响应并结合微生物群落动态变化展开分析。本研究搭建两套串联连续搅拌釜式反应器（Continuously Stirred Tank Reactor, CSTR），分别命名为主消化器（Main Digester, MD）与后消化器（Post Digester, PD），用以模拟现有规模化沼气工程的实际运行工况。两套反应器均遭遇工艺扰动，具体表现为沼气产量下降、pH值波动及中间降解产物积累。为缓解上述工艺问题，本研究评估了多种运维调控手段，包括调整进料间隔、液体回流及全沼液回流。其中，将后消化器出料流中的部分沼液回流至主消化器，可有效提升整体工艺稳定性。