Modeling cell aggregate morphology during aerobic granulation in activated sludge processes reveals the combined effect of substrate and shear
Modeling cell aggregate morphology during aerobic granulation in activated sludge processes reveals the combined effect of substrate and shear
复制标题
对活性污泥过程中好氧颗粒化期间的细胞聚集体形态进行建模揭示了基质和剪切力的综合影响
DOI：
10.1016/j.watres.2019.115384
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发表时间：
2020
期刊：
影响因子：
12.8
通讯作者：
Ducoste, Joel J.
中科院分区：
文献类型：
--
作者：
Wu, Jun;de los Reyes, Francis L.;Ducoste, Joel J.
以往对好氧颗粒污泥技术（AGS）的研究主要集中在宏观环境因素，如沉降时间、投料方式、有机负荷率（OLR）、污泥停留时间（SRT）等，以及它们对颗粒化过程的影响。然而，生物质造粒过程受到这些生物质聚集体周围的微环境的显著影响。本研究采用计算机模拟的方法研究了微环境对生物质颗粒化过程的影响。基于元胞自动机算法和计算流体动力学的2-D生物膜模型被用来模拟特定的流体动力学和基质可用性条件下的单个生物质聚集体的发展。模拟结果表明，剪切和散装基质浓度相结合，创造好氧颗粒形成的最佳条件。该过程可以通过RT（逆Thiele）模量值来表征，RT模量值是最大底物传输与最大底物反应速率的比率，并且是底物可用性的指标。对于AGS形成，RT值应大于0.1。RT值可以解释生物质颗粒化生产的许多常见策略，如间歇反应器的应用，选择生长缓慢的微生物，F/M（食物/质量）比调整，盛宴和饥饿条件，以及短沉降时间。结果表明，重新思考在废水处理设施的单元工艺配置将需要实现可靠的AGS形成。
Past research on AGS (aerobic granular sludge technology) has mainly focused on macro-environment factors, such as settling time, feeding pattern, OLR (organic loading rate), SRT (sludge retention time), among others, and their effects on the granulation process. The biomass granulation process, however, is significantly affected by the micro-environment surrounding these biomass aggregates. In this research, anin silicocomputational approach was adopted to study the impact of the micro-environment on the biomass granulation process. A 2-D biofilm model based on the cellular automata algorithm and computational fluid dynamics was used to simulate the development of an individual biomass aggregate under specific hydrodynamic and substrate availability conditions. The simulation results indicated that shear and bulk substrate concentration combined to create the optimal conditions for aerobic granule formation. This process can be characterized by the RT (reversed Thiele) modulus value, which is the ratio of the maximum substrate transport over the maximum substrate reaction rate and an indicator of substrate availability. For AGS formation, the RT value should be greater than 0.1. Many common strategies, such as the application of batch reactors, selection for slow-growing microorganism, F/M (food/mass) ratio adjustment, feast and famine condition, and short settling time, for biomass granulation production can be explained by the RT value. The results suggest that rethinking unit process configurations in wastewater treatment facilities will be required to achieve reliable AGS formation.