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

过量的营养氮(N)是影响环境和公众健康的主要污染物；因此，必须从废水(WW)中去除过量的N。传统的营养氮去除技术依赖于一系列称为硝化-反硝化的两个微生物过程。第一步(硝化)涉及将铵氧化成硝酸盐。缺点是硝化作用需要投入大量的能量来使水曝气。第二步(反硝化)包括将硝酸盐还原为无害的元素氮气。缺点是，硝酸盐还原需要宝贵的化学能量，这些能量本可以更好地用于制造富含甲烷的沼气等生物燃料。利用厌氧氨氧化(Anammox)细菌可以提高营养氮去除的经济性。Anammox将亚硝酸盐和氨转化为元素氮气，不需要任何曝气或化学能。作为一种技术，厌氧氨氧化必须与部分曝气相结合才能将大约一半的氨氮(部分亚硝化)转化为亚硝酸盐，但与传统的营养氮去除工艺相比，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氨氮、低有机物的成熟技术，例如，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水中70%-85%的N负荷。提出的策略是利用富氨侧流培养的高活性厌氧氨氧化污泥和上流式厌氧污泥床(UASB)反应器对另一条处理主流的UASB进行生物强化。这些反应器将通过曝气引入亚化学计量的元素氧，作为单级部分亚硝化厌氧氨氧化工艺运行。拟议工作的智力价值是将富铵侧流所体现的高氮负荷的责任转化为主流生物脱氮的资产。关键的科学/工程问题是，在主流情况下，由于来自异养菌的竞争和低N浓度的竞争，Anammox的生长和持续条件不太有利，能否利用高浓缩Anammox污泥的生物强化来强化N处理过程。PIS将探索一种新的分层，部分亚硝化和厌氧氨氧化分别在同一污泥颗粒的微好氧外部和缺氧内部进行。通过动力学、代谢和后基因组/转录组分析，PI将通过提供生物标记物来定量监测厌氧氨氧化污泥中所含的厌氧氨氧化细菌，从而确定浓缩的厌氧氨氧化污泥是否在主流中恶化。他们还将获得有关微生物种群组成和功能变化的信息。该项目直接解决了美国国家工程院的重大挑战，即通过开发节能技术来控制环境中过量营养氮的负荷，从而改善氮循环的管理。两名博士生将在地区废水回收设施与Goali合作伙伴合作，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.