Research And Design Of Process Stability Detection System In Anaerobic Digestion Of Food Wastes

The anaerobic digestion of food waste can reduce the pollution and producemethane，this technology has been widely used. However, the single-phase anaerobicdigestion of food wastes would cause instability easily, especially under high loadingrate. In order to maintain stability, it often takes operators much money and time tomake the reactors run under low load operation in industrial scale anaerobic reactor. Toensure the efficient and stable operation of anaerobic digestion system, the applicationof large-scale technical problems had to be solved. Based on this phenomenon, Thisstudy put forward a general stable index according to the constant research on thedisturbance of the food waste anaerobic digestion system and the effectiveness of stateparameter to make the managers have enough time to regulating it. On the basis of thesystem, the author intends to develop the online technique of advanced warningindicators，and develop the device of intelligent monitoring equipment combined withthe automatic control system in order to ensure anaerobic digestion system work well,.Finally, this paper explores the relationship between the microbial community dynamicsand the system stability, preliminarily explores the instability mechanism of the reactor.The main contents and conclusions are as follows:①Different from traditional analysis, This study analyzed and compared thedisturbance evaluation of different conditions in the anaerobic digestion system and putforward three stabilization system indexes，conventional index, buffer basicity indexand volatile acids based on the constant research on the disturbance of the anaerobicdigestion system and the effectiveness of state parameter. In order to evaluate thestability of anaerobic digestion reactor comprehensively, complete the index, anddetermine the inhibition of criterion and warning threshold, the author sets up auniversal warning applicability, sensitivity and stability of anaerobic digestion of earlywarning index system. The stabilization index can achieve comprehensive, rapid andeffective early warning; it has universal applicability in different systems, and can givewarnings1-9days before process failure occurred than conventional indicators (such aspH, gas production, etc.). The joint use of these indicators can reflect the metabolism ofthe digesting system and realize rapid and effective early warning.②Due to high solid content and complex component of anaerobic digestion liquidin food waste anaerobic digestion, a joint method is mentioned of hierarchical and a gradually filtering is proposed. This method ensures the subsequent determination ofcritical warning parameters in fermented liquid. At the same time, Researchers improvetraditional joint titration process and put forward a kind of determination of totalalkalinity, bicarbonate alkalinity, total volatile acid fatty.③Due to high solid content of anaerobic digestion liquid in food waste anaerobicdigestion, and on the basis of the security of the early warning index system and a newmonitoring method, This study design and develop intelligent monitoring system forfood waste anaerobic digestion system. The system includes three parts, filteringpre-processing system, stabilizing index monitoring system and control systemrespectively. This system can test the indicators in the water of liquid parameters onlinemonitoring. In addition, the rest have the commercial application of gas-liquidmonitoring indicators, the device’s software system can also realize the security of earlywarning index system of detection and display, and the running status of intelligentjudgment according to the results of the monitoring system implementation field orremote alarm.④Using454high-through put sequencing analyzed the shift of microbialcommunity succession in the anaerobic digester, in which food waste was as substrate.It concluded that system instability and food waste with high oil, high salt and highprotein features is closely related. In specific, Proteiniphilum species become dominantfungi genera of the system in the late of acidification which can degrading protein andLVFA，it increased from original1.0%to33.96%. Meanwhile, due to salt restrain,Methanospirillum decreased from35.35%to0.46%in acidification.