Collaborative Research: WERF: GOALI: Bioaugmentation-Enhanced Anammox for Mainstream Nitrogen Removal

营养氮(N)超标是影响环境和公众健康的主要污染物；因此，过量的氮必须从废水（WW）中去除。传统的营养物氮去除技术依赖于被称为硝化-反硝化的两个微生物过程序列。第一步（硝化）是将铵氧化为硝酸盐。缺点是硝化需要大量的能量输入来给水充气。第二步（反硝化）是将硝酸盐还原为无害的元素氮气。缺点是硝酸盐的还原需要宝贵的化学能，而硝酸盐可以更好地用于制造生物燃料，如富含甲烷的沼气。厌氧氨氧化（anammox）细菌可以提高去除营养物n的经济性。厌氧氨氧化将亚硝酸盐和铵转化为单质氮气，而不需要曝气或化学能。厌氧氨氧化必须与部分曝气相结合，才能从大约一半的铵中生成亚硝酸盐（部分硝化），但与传统的营养物n去除相比，该工艺节省了57%的曝气成本和100%的化学能需求。厌氧氨氧化已成为处理高铵、低有机质污水的成熟技术，如厌氧消化污泥脱水产生的污泥液侧流，占污水处理厂氮负荷的15-30%。本研究的目的是将厌氧氨氧化应用于污水处理厂主流氮负荷的70-85%。提出的策略是利用富铵侧流培养的高活性厌氧氨氧化污泥与上流式厌氧污泥毯（UASB）反应器对另一个UASB处理主流进行生物强化。反应器将作为单阶段部分硝化厌氧氨氧化过程运行，通过曝气引入亚化学计量量的单质氧。所提出的工作的智力优点是将富铵侧流所体现的高氮负荷的负债转化为主流生物脱氮的资产。关键的科学/工程问题是，在主流环境中，由于异养细菌和低氮浓度的竞争，厌氧氨氧化污泥的生长和维持条件不太有利，是否可以利用高富集厌氧氨氧化污泥的生物强化来提高氮处理过程。pi将分别在相同污泥颗粒的微氧外部和缺氧内部探索部分硝化和厌氧氨氧化的新分层。通过动力学、代谢和宏基因组学/转录组学分析，pi将通过提供生物标记物来定量监测其所含的厌氧氨氧化菌，从而确定富集的厌氧氨氧化污泥在主流中是否会变质。他们还将获得有关微生物种群的变化组成和功能的信息。该项目直接解决了国家工程院的重大挑战，即通过开发节能技术来控制过量营养氮进入环境的负荷，从而改善氮循环的管理。两名博士生将与GOALI合作伙伴一起在区域废水回收设施工作，以获得工业经验。

Krzmarzick1705088Nutrient nitrogen (N) in excess is a major pollutant affecting the environment and public health; consequently, excess N must be removed from wastewater (WW). Conventional nutrient N-removal technology relies on a sequence of two microbial process known as nitrification-denitrification. The first step (nitrification) involves the oxidation of ammonium to nitrate. The drawback is that nitrification requires a large input of energy to aerate the water. The second step (denitrification) involves the reduction of nitrate to harmless elemental nitrogen gas. The drawback is that valuable chemical energy is required for the nitrate reduction that could be better used to make biofuels such as methane-rich biogas. Improvements in the economy of nutrient N-removal can be achieved with anaerobic ammonia oxidizing (anammox) bacteria. Anammox converts nitrite and ammonium to elemental nitrogen gas without any need for aeration or chemical energy. As a technology anammox must be combined with partial aeration to form nitrite from about half of the ammonium (partial nitritation), but this process saves 57% of the aeration costs and 100% of the chemical energy demand compared to conventional nutrient N-removal.Anammox has become a mature technology for the treatment of high ammonium, low organic matter WW, exemplified by sludge liquor side streams from the dewatering of anaerobically digested sludge, which accounst for 15-30% of the N load at wastewater treatment plants (WWTP). The objective of this research is to apply anammox to the 70-85% of the N-load in the mainstream of a WWTP. The strategy proposed is based on utilizing highly active anammox sludge cultivated on the ammonium rich side stream with an upflow anaerobic sludge blanket (UASB) reactor to bioaugment another UASB treating the mainstream. The reactors will be operated as a single-stage partial-nitritation anammox process by introducing substoichiometric quantities of elemental oxygen via aeration. The intellectual merit of the proposed work is to convert the liability of the high N-loading embodied by the ammonium rich side stream into an asset for biological N-removal for the mainstream. The key scientific/engineering question is whether bioaugmentation of highly enriched anammox sludge can be used to enhance the N-treatment process in the mainstream where conditions are less favorable for growing and sustaining anammox due to competition from heterotrophic bacteria and low N concentrations. The PIs will explore a novel stratification of partial nitritation and anammox in the microaerophilic exterior and anoxic interior of the same sludge particles, respectively. Through kinetic, metabolic and metagenomic/transcriptomic analyses, the PIs will determine whether the enriched anammox sludge deteriorates in mainstream by providing biomarkers to quantitatively monitor the anammox bacteria they contain. They will also obtain information on the shifting composition and function of the microbial population. The project directly addresses the National Academy of Engineering grand challenge of improving the management of the N cycle by developing energy saving technology to control the load of excess nutrient-N into the environment. Two PhD students will be working with the GOALI partner at the regional wastewater reclamation facility to gain industrial experience.