EAGER: Feasibility Study of Micro-Level Sensing and Process Control of Nitrification

这个项目的目的是证明集成了“片上”传感的微生物反应器可以在各种剪切应力和质量传输条件下研究微生物的过程动力学。这种微生物反应器概念将允许研究低剪切应力与快速质量输运相结合的条件，这在目前较大的实验规模反应器中是无法实现的。本项目研究的目标微生物为硝化菌。这些细菌依次将氨氧化为亚硝酸盐和硝酸盐，从而使其易于随后还原为二氮气体。硝化细菌在自然和工程环境中都发挥着重要作用，因为它们在全球氮循环中发挥着重要作用，例如在废物管理方面。与目前使用的基准反应器相比，微生物反应器具有固有的变革性优势。它们具有比大型反应器更均匀的流动条件，直接光学通道和大的表面体积比，以增强传质。例如，可渗透膜用于气体扩散，而不是传统的鼓泡技术，后者会增加剪切应力。亚硝酸盐浓度和温度的控制和测量将使用光学和微加工技术来实现。更广泛的影响pi将在他们的研究生课程“微尺度传输现象”中传播研究结果。本科生和高中生将参与这项跨学科研究，这是PI和co-PI研究实验室的惯例。这项探索性研究将为提交用于废水处理的硝化生物反应器工程的完整尺寸提案提供基础，有效克服目前观察到的传质限制。这项研究将整合到哥伦比亚大学与工业（IBM“智慧城市”）和化学工程系的协同活动中，以使这项工作成为可能的国家科学基金会研究中心。

1025685AttingerIntellectual meritThe aim of this project is to prove the concept that microbioreactors with integrated "on-chip" sensing can investigate the process kinetics of microorganisms under a wide array of shear stress and mass transport conditions. This microbioreactor concept will allow the study of low shear stress in combination with fast mass transport, conditions that are not attainable in current larger bench scale reactors. The target microorganisms investigated in this project are nitrifying bacteria. These bacteria sequentially oxidize ammonia to nitrite and nitrate and thus render it amenable for subsequent reduction to dinitrogen gas. Nitrifying bacteria play an important role in both natural and engineered environments due to their role in the global nitrogen cycle, for instance in relation to waste management. Microbioreactors have inherent, transformative advantages over currently used benchscale reactors. They feature more homogeneous flow conditions than larger reactors, direct optical access and large surface to volume ratio, for enhanced mass transfer. For instance, permeable membranes are used for gas diffusion, rather than traditional bubbling techniques that come with increases in shear stress. Control and measurement of nitrite concentration and temperature will be implemented using optical and microfabrication techniques.Broader impactThe PIs will disseminate the results in their graduate course "Microscale Transport Phenomena". Undergraduate and High School students will be involved in this interdisciplinary research, a practice that is customary to the research laboratories of both the PI and co-PI. This exploratory research will provide a foundation for the submission of a full size proposal to engineer nitrifying bioreactors for wastewater treatment, effectively overcoming currently observed mass-transfer limitations. This research will integrate into synergistic activities of Columbia University with industry (IBM "Smarter Cities") and with the Department of Chemical Engineering to grow this effort into a possible NSF research Center.