Three-Dimensional Visualization of Oxygen Distribution in Wastewater Biofilm

Abstract

Three-dimensional (3-D) visualization of the distribution of chemical species of interest in biofilms enhances our understanding of important structural and functional characteristics of biofilms. In a previous study, the 3-D oxygen distribution in an approximately 1 mm3 wastewater biofilm was mapped by using oxygen microsensor. However, there has been a lack of method for effective visualization of 3-D oxygen distribution in biofilms. This study developed a Matlab package for 3-D visualization of oxygen distribution in wastewater biofilm as well as on and near biofilm surface. In the package, colormap slices, contour slices, isosurfaces, and animations were used for the visualization. It was found that the oxygen pockets in deep sections of biofilm existed in isolation, which indicates that the biofilm is physiologically heterogeneous. The oxygen concentration on the biofilm surface was observed to be much lower than that of bulk liquid phase, indicating a high intensity of metabolic activity in biofilm. The interception line between biofilm surface and horizontal slice was clearly visualized, which is helpful for comparing the vertical distribution of bacteria biovolume along the biofilm depth. The visualization method in this study will greatly help researchers to understand the 3-D heterogeneity of biofilms, and to gain more insight for the structural and functional features of wastewater biofilms. This Matlab package developed in this study can also support 3-D visualization of other chemical species of interest in biofilms where data are available.