摘要
为了解微生物生长过程中生物堵塞对二维饱和多孔介质渗透性的影响,采用C190石英砂箱(55 cm×45 cm×1.28 cm)进行室内渗流实验,研究混合菌群KB-1在充足营养源条件下的生长情况及生物膜对饱和多孔介质渗透性的影响.实验监测了砂箱水溶液中悬浮生物量及颗粒表面附着生物量,利用共焦激光扫描技术观测了颗粒表面形成的生物膜及其厚度,利用渗流实验测量渗透率.结果表明,砂箱中微生物量随时间不断增加;砂箱底部微生物量的增长大于砂箱上部;高生物量区颗粒表面生物膜厚度比低生物量区厚.渗流实验结果表明,生物膜导致实验砂箱多孔介质的平均渗透率减少为初始渗透率的12%.为了解二维实验砂箱多孔介质渗透率的空间变化,以实验所得生物膜和生物量数据为基础,采用Taylor、Seki、Clement这3种模型分别计算了生物膜影响下的渗透率.计算结果表明,Taylor模型预测渗透率减小2～5个数量级;Clement模型预测渗透率为初始渗透率的3%～98%;Seki模型则不适用于本实验结果.可见,二维条件下生物膜会明显降低饱和多孔介质的渗透性,但和前人一维条件下的研究结果相比,渗透率的变化要小得多.此外,在二维饱和多孔介质且营养源充足条件下预测生物膜对渗透率的影响,Seki模型不适用,Taylor模型计算的kb值偏小,Clement模型计算的kb值涵盖了实验结果.
This paper studied on the influence of bioclogging on permeability of saturated porous media·Laboratory hydraulic tests were conducted in a two-dimensional C190 sand-filled cell（55 cm wide × 45 cm high × 1.28 cm thick） to investigate growth of the mixed microorganisms（KB-1） and influence of biofilm on permeability of saturated porous media under condition of rich nutrition.Biomass distributions in the water and on the sand in the cell were measured by protein analysis.The biofilm distribution on the sand was observed by confocal laser scanning microscopy.Permeability was measured by hydraulic tests.The biomass levels measured in water and on the sand increased with time,and were highest at the bottom of the cell.The biofilm on the sand at the bottom of the cell was thicker.The results of the hydraulic tests demonstrated that the permeability due to biofilm growth was estimated to be average 12% of the initial value.To investigate the spatial distribution of permeability in the two dimensional cell,three models（Taylor,Seki,and Clement） were used to calculate permeability of porous media with biofilm growth.The results of Taylor＇s model showed reduction in permeability of 2-5 orders magnitude.The Clement＇s model predicted 3%-98% of the initial value.Seki＇s model could not be applied in this study.Conclusively,biofilm growth could obviously decrease the permeability of two dimensional saturated porous media,however,the reduction was much less than that estimated in one dimensional condition.Additionally,under condition of two dimensional saturated porous media with rich nutrition,Seki＇s model could not be applied,Taylor＇s model predicted bigger reductions,and the results of Clement＇s model were closest to the result of hydraulic test.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2011年第5期1364-1371,共8页
Environmental Science
基金
国家自然科学基金项目(40872155
40725010)
关键词
生物堵塞
渗透率
生物膜
二维
多孔介质
模型
bioclogging
permeability
biofilm
two dimensional
porous media
model
