A large fraction of the chemical oxygen demand (COD) in municipal wastewater is associated with the particulate matter. The presence of these particles might impose a negative impact on the mass transfer in biofilm systems when they attach to the bulk-biofilm interface. We thus investigated the impact of real wastewater particles by combining optical coherence tomography (OCT) and oxygen microsensor measurements. The deposition of wastewater particles of different size classes onto the biofilm surface was captured in 3D by means of OCT in a lab-scale flume. The thickness of the particle layer was calculated from OCT images. The influence of the particle deposition with respect to oxygen mass transfer into the biofilm was monitored by measuring oxygen profiles before and after particle deposition. By employing OCT, the formation of the particle layer on the biofilm surface was monitored in situ and non-invasively over time. Results from oxygen microsensor measurements concluded 20–70% reduction of the dissolved oxygen flux from the biofilm surface into the biofilm matrix. This decrease in oxygen availability lowered substrate conversion in biofilms exposed to high loadings of organic wastewater particles.

城市废水中化学需氧量（COD）的很大一部分与颗粒物有关。当这些颗粒附着在生物膜的整体界面上时，它们的存在可能会对生物膜系统中的传质产生负面影响。因此，我们通过结合光学相干断层扫描（OCT）和氧气微传感器测量来研究实际废水颗粒的影响。通过OCT在实验室规模的水槽中以3D方式捕获了不同尺寸类别的废水颗粒在生物膜表面上的沉积。从OCT图像计算颗粒层的厚度。通过测量颗粒沉积之前和之后的氧分布来监测颗粒沉积相对于氧质量转移到生物膜中的影响。通过使用OCT，随着时间的推移就地和非侵入性地进行。氧气微传感器的测量结果表明，从生物膜表面到生物膜基质的溶解氧通量减少了20-70％。氧气利用率的下降降低了暴露于高负荷有机废水颗粒的生物膜中的基质转化率。