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.

根据英国环境局的说法，从废水到环境的NH4+和NO3-排放持续存在问题，对水生生态，饮用水资源和人类健康造成了伤害。在市政废水处理中，硝化和硝化细菌的组合通常用于将NH4+转换为NO3-，然后将其转换为N2气体。但是，有氧NH4+氧化过程消耗了大量能量（用于充气），并且昂贵。一种有吸引力的替代方法是使用厌氧氨氧化（Annamox）细菌，该细菌通过将NH4+和NO2-直接转换为N2来提供“快捷方式”。一个关键的好处是，Anammox过程是厌氧，这意味着不需要消耗的充气。估计部分硝化/ANAMMOX过程需要0.3 G-O2/G-N-比常规硝化/硝化中使用的4.57 G-O2/G-N小得多。此外，Annamox不使用外部有机碳，因此将能源消耗降低了60％，加上外部化学品的节省成本。 尽管Anammox是解决急性环境问题的有前途的替代方法，但其应用目前仅限于高NH4+浓度废水（来自污泥消化的侧面流）。主流污水处理和基于自然的解决方案（例如，建造的湿地）的应用提出了一些挑战，尤其是如何固定厌氧菌细菌并保持其活性。由于长期保留时间，保护性矩阵和特种间相互作用，自然出现的生物膜是最适合Anammox生长的“栖息地”。不幸的是，天然的Anammox生物膜生长速度很慢。成熟的Anammox生物膜很容易分解并失去其活性，尤其是在英国的低温废水中。我们的突破性想法是通过将Anammox细菌封装在水性聚合物中以制造工程“生物胶化”来开发一种“合成生物膜”。我们假设我们的生物涂料将机械保护细菌，将增加对生物反应器内部载体的粘附，并将其表面上的自然生物膜生长播种。我们将添加电导的纳米颗粒（ECNP），例如纳米线和C纳米管，提供桥梁以刺激细胞外电子转移（EET），以加速Anammox过程中的NH4+氧化速率。我们推测ECNP将为外部电子受体（NO2-除外）提供传导途径，从而停止有害温室气体N2O的产生。没有先前关于Anammox biocoatings的报道，可以证实研究新颖性。我们最近在其他细菌物种中有杀菌剂的经验。