Biofilm with highly heterogeneous interior structure for pollutant removal : Effects of individual extracellular polymeric substance

For the first time, this study reveals the effects of an individual component of extracellular polymeric substances on the substrate consumption rates by the embedded cells based on the highly heterogeneous interior structures of a working biofilm. The flow-across mode in operation established a boundary-layer flow field with high transport resistance, making the uniformly structured model valid. Conversely, the flow field of the flow-through mode is determined by 46% jointly by proteins and β-D-glucopyranose polysaccharides. The substrate consumption rates hindered by β-D-glucopyranose polysaccharide is up to 60% over the 20%−40% biofilm height from the bottom, much lower than expected by the uniformly structured models. The strategies to maximize the biofilm performance have been suggested.