Fluidized bed bioreactors are widely used in wastewater treatment applications. Such reactors employ gel beads or hard particles covered with a biofilm layer. These particles lose more energy due to deformation when they collide than particles with high mechanical resistance. This energy loss can result in heterogeneity in particle distribution, increasing the drag on them, which, if not considered properly, can lead to problems in reactor design and operation. Therefore, it is important to know how much energy is dissipated by particles with low mechanical strength during collisions. In this context, the coefficient of restitution of alginate particles synthesized using different cationic solutions was determined experimentally. The influence of the Young’s modulus, size and roughness of the particles, as well as the impact velocity, on the coefficient of restitution was investigated. Results indicate that the coefficient of restitution is directly proportional to the particle Young's modulus and inversely proportional to the impact velocity. A correlation is proposed to estimate the coefficient of restitution as a function of particle density, Young’s modulus, impact velocity and maximum deformation in the elastic regime, with R² = 0.9219. This correlation provides a potential tool for determining the coefficient of restitution to be used in simulating the dynamics of the flow in fluidized bed bioreactors in wastewater treatment.

Graphic abstract

中文翻译：

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具有低机械阻力的颗粒恢复系数的新型相关性，用于模拟废水处理生物膜反应器

流化床生物反应器广泛用于废水处理应用中。这样的反应器采用凝胶珠或覆盖有生物膜层的硬颗粒​​。与具有高机械阻力的颗粒相比，这些颗粒在碰撞时由于变形而损失更多的能量。这种能量损失会导致颗粒分布不均匀，增加对颗粒的阻力，如果考虑不当，则会导致反应堆设计和运行出现问题。因此，重要的是要知道在碰撞过程中具有低机械强度的颗粒会消耗多少能量。在这种情况下，实验确定了使用不同阳离子溶液合成的藻酸盐颗粒的复原系数。杨氏模量，颗粒尺寸和粗糙度以及冲击速度的影响，对恢复系数进行了研究。结果表明，恢复系数与颗粒的杨氏模量成正比，与冲击速度成反比。提出了一种相关性，以估算恢复系数与颗粒密度，杨氏模量，冲击速度和弹性状态下的最大变形的关系，其中R ²  ＝ 0.9219。这种相关性提供了一种潜在的工具，用于确定恢复系数，该恢复系数可用于模拟废水处理中流化床生物反应器中的流动动力学。

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