INFLUENCE OF BIOFILM ACCUMULATION ON POROUS-MEDIA HYDRODYNAMICS
INFLUENCE OF BIOFILM ACCUMULATION ON POROUS-MEDIA HYDRODYNAMICS
复制标题
生物膜积累对多孔介质流体力学的影响
DOI：
10.1021/es00019a013
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发表时间：
1991-07-01
影响因子：
11.4
通讯作者：
CRAWFORD, D
中科院分区：
文献类型：
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作者：
CUNNINGHAM, AB;CHARACKLIS, WG;CRAWFORD, D
采用实验室规模的多孔介质生物膜反应器来评估生物膜积累对介质孔隙度、渗透率和摩擦系数的影响，生物膜积累以沿50毫米流动路径的平均厚度来测量。测试介质包括1 mm玻璃球、0.70 mm砂、0.54 mm砂和0.12 mm玻璃砂。以铜绿假单胞菌为接种物，连续向反应器提供25 mg L-1葡萄糖底物。反应器在恒定压头条件下运行，导致流速随着生物膜的形成而降低。生物膜厚度的变化呈s型曲线，约5天后达到最大厚度。随着生物膜积累的增加，介质孔隙度降低50% ~ 96%，渗透率降低92% ~ 98%。多孔介质摩擦系数在所有测试介质中均显著增加。对生物膜介质基质渗透率的观察表明，在生物膜厚度达到最大值后，最小渗透率[(3-7)x10 (-8) cm2]持续存在。这些结果表明，多孔介质中流体-生物膜界面的质量传递、流体动力学和生物膜积累之间存在着实质性的相互作用。对这些相互作用的更好理解将导致在生物湿法冶金、提高石油采收率以及污染地下水和土壤的生物修复方面的工业和环境应用。
Laboratory-scale porous media biofilm reactors were used to evaluate the effect of biofilm accumulation, measured as the average thickness along a 50-mm flow path, on media porosity, permeability, and friction factor. Media tested consisted of 1-mm glass spheres, 0.70-mm sand, 0.54-mm sand, and 0.12-mm glass and sand. Pseudomonas aeruginosa was used as inoculum and 25 mg L-1 glucose substrate was continuously supplied to the reactor. Reactors were operated under constant piezometric head conditions resulting in a flow rate decrease as biofilm developed. The progression of biofilm thickness followed a sigmoidal-shaped curve reaching a maximum thickness after approximately 5 days. Media porosity decreased between 50 and 96% with increased biofilm accumulation while permeability decreased between 92 and 98%. Porous media friction factor increased substantially for all media tested. Observations of permeability in the biofilm-media matrix indicate that a minimum permeability [(3-7) X 10(-8) cm2] persisted after biofilm thickness has reached a maximum value. Such results indicate substantial interaction between mass transport, hydrodynamics, and biofilm accumulation at the fluid-biofilm interface in porous media. Improved understanding of these interactions will lead to industrial and environmental applications in biohydrometallurgy, enhanced oil recovery, and bioremediation of contaminated groundwater and soil.