Biofilm reactors are an alternative technology to the conventional activated sludge process for treating wastewater. Understanding the microbial activity microdistribution in heterogeneous biofilms will enable exploration of microbial microdistribution, substrate transfer, and reaction processes inside biofilms. However, the microbial activity obtained from models and the reported measurement techniques are imprecise and complex, respectively. In this study, a convenient approach for estimating the relative microbial oxygen metabolic activity microdistribution inside biofilms is proposed. The oxygen-infusion processes within the biofilm produced by a rotating biological contactor (RBC) were measured by an oxygen microelectrode system. The measurement results showed that there were regular catastrophe points of dissolved oxygen (DO) concentration vs. time, and the DO concentration change rate increased notably at the catastrophe points. This catastrophe point phenomenon was observed for the first time and was analyzed using the three-dimensional diffusion-reaction model. Based on the analysis, it appears that the catastrophe point begins the biomass-limited stage. These points can be used to estimate the relative microbial oxygen metabolic activity microdistribution inside biofilms. This proposed method is convenient and less destructive than other methods. This approach enables the exploration of oxygen transfer-reaction micro-processes, dynamic OUR microdistribution, and microbial microdistribution inside biofilms.

中文翻译：

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基于输氧过程中的突变点现象估算生物膜中相对氧代谢活性的微分布

生物膜反应器是用于处理废水的常规活性污泥工艺的替代技术。了解异质生物膜中的微生物活性微分布将使人们能够探索生物膜内部的微生物微分布，底物转移和反应过程。然而，从模型和所报道的测量技术获得的微生物活性分别是不精确的和复杂的。在这项研究中，提出了一种方便的方法来估算生物膜内相对微生物氧代谢活性的微分布。通过氧气微电极系统测量了旋转生物接触器（RBC）产生的生物膜内的氧气注入过程。测量结果表明溶解氧（DO）浓度存在规律的突变点随时间变化，DO浓度变化率在灾难点显着增加。首次观察到该突变点现象，并使用三维扩散反应模型对其进行了分析。基于分析，看来灾难点开始了生物量限制阶段。这些点可用于估计生物膜内相对微生物氧代谢活性的微分布。所提出的方法比其他方法方便且破坏性较小。这种方法使得能够探索生物膜内部的氧转移反应微过程，动态OUR微分布和微生物微分布。