基于CFD模拟的混合菌群合成PHA工艺筛选机制分析

OPTIMIZATION OF THE PHYSICS PRESSURE UNDER ADD MODE IN PHA PRODUCTION WITH CFD SIMULATION

利用数值模拟方法,建立了活性污泥混合菌群合成PHA工艺中ADD与ADF模式反应器的流体有限元分析模型,同时基于固液二相流体理论对ADD和ADF模式的沉淀过程进行分析,探讨了物理选择压的产生原理和作用机制。模拟获得了沉淀过程中不同停留时间反应器内不同沉降速率等级活性污泥的分布规律,以及沿反应器竖向方向的污泥体积分数分布规律。结果表明:ADD模式下活性污泥在沉淀过程中可形成较为稳定的沉降性差异分层界线,反应开始10~15 min内在高度为0.6 m处污泥分布体积分数为0.75左右,可对PHA合成能力强的菌群提供较强的筛选作用。固液二相流体场的模拟结果促进了对物理选择压筛选作用机制的认识,可为ADD模式反应器参数优化研究提供理论依据。

Numerical simulation method was used to establish the fluid finite element analysis model of PHA accumulating by the mixed microbial culture(MMC)under aerobic dynamic discharge(ADD)and aerobic dynamic feeding(ADF)mode.The precipitation process was analyzed to discuss the generation principle and mechanism of physical selective pressure.The simulation obtained the distribution law of activated sludge with different sedimentation rate grades in the reactor with different residence times during the sedimentation process,and the distribution law of the sludge volume fraction along the vertical direction of the reactor.The results showed that the activated sludge in the ADD mode could form a relatively stable sedimentation difference stratified boundary during the sedimentation process.The sludge distribution volume fraction at a height of 0.6 m was about 0.75 within a residence time of 10~15 minutes,which provided a strong screening effect on the MMCs with strong PHA accumulating ability.The analysis process based on numerical simulation technology promoted the understanding of the mechanism of physical selective pressure screening,and could provide a theoretical basis for the optimization of parameters under ADD mode.