Fluid transport in porous media based on differences in filter media morphology and biofilm growth in bioreactors
Fluid transport in porous media based on differences in filter media morphology and biofilm growth in bioreactors
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基于生物反应器中过滤介质形态和生物膜生长差异的多孔介质中的流体输送
DOI：
10.1016/j.envres.2022.115122
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发表时间：
2022
影响因子：
8.3
通讯作者：
Yongchao Zhou
中科院分区：
文献类型：
--
作者：
Ping Tang;Henglei Xu;Wenming Zhang;Yixuan Zhu;Jin Yang;Yongchao Zhou
为了阐明孔隙结构对生物反应器中生物堵塞和渗流的影响，我们采用x射线计算机断层扫描（X-CT）技术，通过注入非离子型造影剂碘己醇，研究了沸石、砾石和陶粒生物反应器中多孔介质在生物膜生长过程中的渗流变化。基于采用球棒模型的X-CT图像，发现陶粒柱在初始条件下具有最高的平均孔隙半径(R)和平均孔喉半径(R)，这有利于陶粒柱的渗透性。砾石柱的孔喉较小且相对均匀。生物膜的生长使柱孔和孔喉减小。沸石柱、砾石柱和陶粒柱的总喉道面积分别减小了74%、73%和79%。沸石柱具有最高的平均孔喉，这有助于其在生物膜生长后的最大电导率。此外，孔隙结构的分形维数随着生物膜的生长而增加，特别是在沸石和陶粒柱中。由于沸石和陶粒柱的非均质性较高，生物膜的生长增强了多孔介质的非均质性。我们还观察到多孔介质非均质性的增加放大了优先流和流动非均质性，特别是在沸石和陶粒柱中。
To elucidate the effect of pore structure on bioclogging and seepage flow in bioreactors, we used X-ray computed tomography (X-CT) to investigate the changes in seepage flow of porous media in zeolite, gravel and ceramsite bioreactors with biofilm growth by injecting a non-ionic contrast medium iohexol. Based on the X-CT images using a ball-and-stick model, the highest average pore radius (R‾) and the average pore throat radius (r‾) in the ceramsite column were found under the initial conditions, which facilitated its permeability. The pore and throat of the gravel column were small and homogeneous relatively. Biofilm growth decreased the pore and pore throat in the columns. The total throat area of zeolite, gravel and ceramsite columns declined by 74%, 73% and 79% respectively. The zeolite column had the highest average pore throat, which contributed to its maximum conductivity subsequently after biofilm growth. Further, the fractal dimensions of the pore structure increased with biofilm growth, especially in the zeolite and ceramsite columns. The heterogeneity of the porous media was reinforced by the biofilm growth in the zeolite and ceramsite columns due to their higher heterogeneity initially. We also observed that an increase in heterogeneity of porous medium amplified the preferential flow and flow heterogeneities, especially in the zeolite and ceramsite columns.