Engineered Anammox Biofilms for Low-Energy Wastewater Remediation and Environmental Protection

用于低能耗废水修复和环境保护的工程厌氧氨氧化生物膜

• 批准号: 2891771
• 金额: --
• 依托单位: University of Surrey
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2891771
• 关键词: Engineered; Anammox; Biofilms; Low; Energy

According to the UK Environment Agency, there are continuing problems with the discharge of NH4+ and NO3- from wastewater to the environment, causing harm to aquatic ecology, drinking water resources, and human health. In municipal wastewater treatment, combinations of nitrifying and denitrifying bacteria are commonly used to convert NH4+ to NO3- and then to N2 gas. But the aerobic NH4+ oxidation processes consume huge amounts of energy (for aeration) and are costly. An attractive alternative is to use anaerobic ammonia oxidation (annamox) bacteria, which provide a "shortcut" by converting NH4+ and NO2- directly to N2. A key benefit is that anammox processes are anaerobic, meaning no energy-consuming aeration is needed. A partial nitrification/anammox process is estimated to require 0.3 g-O2/g-N - much less than the 4.57 g-O2/g-N used in conventional nitrification/nitrification. Moreover, annamox uses no external organic carbon, thus reducing the energy consumption by 60% plus saving cost on external chemicals. Although anammox is a promising alternative to tackle an acute environmental problem, its application is currently limited to high NH4+ concentration wastewater (side-stream from sludge digestate). Applications to mainstream sewage treatment and nature-based solutions (e.g., constructed wetland) poses several challenges, especially how to immobilize the anammox bacteria and maintain their activity. Naturally-occurring biofilms are the most suitable "habitat" for anammox growth, due to long retention times, protective matrix, and intra-/inter-species interactions. Unfortunately, natural anammox biofilm growth is slow. Mature anammox biofilms easily disintegrate and lose their activity, especially in the UK's low temperature wastewater.Our breakthrough idea is to develop a type of "synthetic biofilm" by encapsulating anammox bacteria in a water-based polymer to make an engineered "biocoating." We hypothesise that our biocoatings will protect the bacteria mechanically, will increase their adhesion to carriers inside of bioreactors, and will seed natural biofilm growth on their surfaces. We will add electrically-conducting nanoparticles (ECNP), e.g. nanowires and C nanotubes, to provide bridges to stimulate extra-cellular electron transfer (EET) to accelerate the NH4+ oxidation rates in the anammox process. We speculate the ECNP will provide conducting pathways to external electron acceptors (other than NO2-), thereby halting the production of the harmful greenhouse gas, N2O. There are no prior reports of anammox biocoatings, which confirms the research novelty. We have recent experience with other bacterial species in biocoatings.

据英国环境署称，废水中NH 4+和NO3-的排放问题持续存在，对水生生态、饮用水资源和人类健康造成危害。在城市污水处理中，硝化细菌和反硝化细菌的组合通常用于将NH 4+转化为NO3-，然后转化为N2气体。但是好氧NH 4+氧化过程消耗大量的能量（用于曝气）并且是昂贵的。一个有吸引力的替代方案是使用厌氧氨氧化（annamox）细菌，它通过将NH 4+和NO2-直接转化为N2提供了一条“捷径”。一个关键的好处是厌氧氨氧化工艺是厌氧的，这意味着不需要消耗能源的曝气。部分硝化/厌氧氨氧化工艺估计需要0.3 g-O2/g-N -远低于常规硝化/硝化中使用的4.57 g-O2/g-N。此外，annamox不使用外部有机碳，因此减少了60%的能源消耗，并节省了外部化学品的成本。 虽然厌氧氨氧化是一种很有前途的替代方案，以解决严重的环境问题，其应用目前仅限于高NH 4+浓度废水（侧流从污泥厌氧状态）。应用于主流污水处理和基于自然的解决方案（例如，人工湿地）提出了一些挑战，特别是如何培养厌氧氨氧化细菌并保持其活性。由于保留时间长、保护性基质以及种内/种间相互作用，天然存在的生物膜是anammox生长最合适的“栖息地”。不幸的是，天然厌氧氨氧化生物膜生长缓慢。成熟的厌氧氨氧化生物膜很容易分解并失去活性，特别是在英国的低温废水中。我们的突破性想法是开发一种“合成生物膜”，将厌氧氨氧化细菌包裹在水基聚合物中，制成工程“生物涂层”。“我们假设我们的生物涂层将机械地保护细菌，增加它们对生物反应器内载体的粘附，并在其表面上种植自然生物膜生长。我们将添加导电纳米颗粒（ECNP），例如纳米线和碳纳米管，以提供桥梁来刺激细胞外电子转移（EET），从而加速厌氧氨氧化过程中的NH 4+氧化速率。我们推测ECNP将提供传导途径到外部电子受体（NO2-除外），从而阻止有害温室气体N2 O的产生。之前没有关于厌氧氨氧化生物涂层的报道，这证实了研究的新奇。我们最近有在生物涂层中使用其他细菌物种的经验。