Bioaugmentation as a strategy to reduce the uncertainty of biological nutrient removal in granular sludge systems

本研究计划将解决与废水处理有关的一个主要问题：如何减少生物去除营养物的不确定性。这项研究的方法将结合数学建模和生物过程工程创新策略的实验测试。去除营养物（氮和磷）在废水处理的总成本中起着主要作用。生物除营养物（BNR）是最经济和环境可持续的先进技术。然而，BNR的设计和运行仍然存在一定程度的不确定性。进行生物降解和营养物去除的微生物群落的选择和分离是目前面临的主要问题。聚磷菌（PAO）的选择是实现磷的可持续去除和回收的有效策略。此外，颗粒污泥技术的最新发展和应用为改善固液分离和减少工厂规模提供了一条有希望的途径，特别是在寒冷气候地区。这两种解决方案并不总是适用于实际技术，这取决于上下文。颗粒污泥的形成表现出与颗粒形成和稳定性有关的一些关键方面，PAO的选择严格依赖于与糖原积累菌的竞争。由于废水流量大，控制废水的一些重要参数（如组成、pH和温度）进行过程控制的成本过高。因此，寻找替代策略来推动植物生态系统的选择是很重要的。我和我的团队提出了一种创新的方法，基于在受控侧流反应器中选择所需的微生物群落，作为主流反应器的连续接种物（生物增强）。这将促进废水处理厂生物去除营养物的设计和运行，并将为环境生物过程工程的新方面提供见解。研究结果将对除BNR以外的环境技术产生潜在影响和未来的应用。

This research program will address a major problem related to wastewater treatment: how to reduce the uncertainty of biological nutrient removal. The approach to the research will combine mathematical modelling and experimental testing of an innovative strategy for bioprocess engineering. The removal of nutrients (nitrogen and phosphorus) plays a major role in the overall cost of wastewater treatment. Biological nutrient removal (BNR) is the most economically and environmentally sustainable state-of-the-art technology. However, a degree of uncertainty is still related to BNR design and operation. The selection and the separation from the liquid of the microbial consortia operating biodegradation and nutrient removal are the main problems to be faced. The selection of phosphorus accumulating bacteria (PAO) is a very effective strategy for a sustainable removal and recovery of phosphorus. Moreover, the recent development and application of granular sludge technologies represents a promising approach to improve solid-liquid separation and to reduce the size of the plants especially in cold climate regions. Both solutions are not always suitable, depending on the context, with actual technologies. Granular sludge formation presents some critical aspects related to granules formation and stability and the selection of PAO strictly depend on the competition with glycogen accumulating bacteria. Due to the high flow rates of wastewater, it is too expensive to control some important parameters of wastewater (such as the composition, pH and temperature) for process control. Thus, it is important to find alternative strategies to drive the selection in the plant ecosystem. My team and I propose an innovative approach, based on the selection of the desired microbial community in a controlled side stream reactor, to be used as continuous inoculum for mainstream reactors (bioaugmentation). This will facilitate the design and operation of wastewater treatment plants for biological nutrient removal and will offer an insight in to new aspects of environmental bioprocess engineering. The results of the research will have a potential impact and future application in environmental technologies other than BNR.