Engineering a better biofilm: Rational design of attachment surface chemistry and morphology to remove nutrients and microconstituents

新墨西哥大学安德鲁·舒勒美国废水处理行业正在努力解决一个关键问题，即保护敏感的污水不受微量化学物质的污染，这些化学物质包括药品、激素和工业化学品。由于这些化合物经常被发现，并且在极低浓度下对生态系统造成破坏，因此受到越来越多的关注。先进的物理化学处理工艺，如反渗透，可以有效地去除许多这些化学物质，但它们的能源消耗和环境后果受到批评，而且对许多社区来说，它们可能成本过高。因此，这些污染物的生物降解是有吸引力的，但在如何设计这种系统以实现高水平性能方面存在关键的知识空白。基于生物膜的系统在废水处理系统中的应用越来越多，主要用于除氮，其中附着的微生物群落生长在淹没在废水中的塑料表面。该项目将评估这样一种假设，即通过有针对性地设计附着介质的化学和物理特性，可以“工程化”生物膜特性，如微生物种群、吸光度特性和具有特定化学特性的微组分的生物降解率。初步结果表明，这些特性可用于生产富含氨氧化细菌（硝化菌）群落的生物膜，也可提高激素的去除率。该项目将包括评估特定细菌（如氨和亚硝酸盐氧化剂）在化学定义明确的表面（自组装单层）上的微生物附着，这些相互作用的建模，以及评估这些表面上的混合培养物。这些结果将用于开发反应器系统，其中使用表面化学来评估表面粗糙度和剪切的附加参数，以确定对功能行为的影响，包括去除目标微成分和代谢活性。该项目将解决从废水中可持续去除微量成分的关键需求，同时提供成本和能源节约。该项目将为如何设计表面来影响生物膜的发展、数量和功能性能提供新的、基本的见解，这将为利用生物膜系统的工艺工程师提供重要的新设计策略。这些结果对于寻求具有成本效益的技术以减少向敏感的接收水排放药物、激素和工业化学品的社区应该非常有用。

CBET 1337077Andrew SchulerUniversity of New MexicoThe U.S. wastewater industry is struggling to solve the critical problem of protecting sensitive receiving waters from microconstituent chemicals, including pharmaceuticals, hormones and industrial chemicals. These compounds are receiving increasing attention due to their frequent detection and their disruption of ecosystems at very low concentrations. Advanced physical-chemical treatment processes, such as reverse osmosis, can be effective at removing many of these chemicals, but their energy consumption and environmental consequences have been criticized, and they can be cost-prohibitive to many communities. Biodegradation of these contaminants is therefore attractive, but there are critical knowledge gaps in how such systems can be designed for high levels of performance. Biofilm-based systems are seeing increasing use in wastewater treatment systems, largely for nitrogen removal, where attached microbial communities are grown on plastic surfaces that are submerged in wastewater. This project will evaluate the hypothesis that biofilm properties, such as microbial populations, absorbance characteristics, and biodegradation rates of microconstituents with specific chemical properties can be "engineered" by targeted design of attachment media chemical and physical characteristics. Preliminary results suggest such properties can be used to produce biofilms with enriched communities of ammonia-oxidizing bacteria (nitrifiers), and also to increase rates of hormone removal. This project will include evaluation of microbial attachment of specific bacteria of interest (e.g., ammonia and nitrite oxidizers) to chemically well-defined surfaces (self-assembled monolayers), modeling of these interactions, and evaluation of mixed cultures on these surfaces. These results will be used to develop reactor systems in which the additional parameters of surface roughness and shear are evaluated, with surface chemistry, to determine effects on functional behaviors, including removal of target microconstituents and cometabolic activity. This project will address the critical need for sustainable microconstituent removal from wastewater, while providing cost and energy savings. The project will provide new, fundamental insights to how surfaces can be designed to influence biofilm development, populations, and functional performance, which should produce important new design strategies for process engineers that utilize biofilm-based systems. These results should be of great use to communities seeking cost-effective technologies to reduce discharges of pharmaceuticals, hormones, and industrial chemicals to sensitive receiving waters.