EAGER: Engineering and Testing a Feammox Bacterium for its use in Nitrogen Removal Bioreactors for Wastewater Treatment

1433101 Jaffe PI及其同事最近在新泽西的湿地土壤中、加州大学伯克利分校的研究人员在热带雨林土壤中以及日本的研究人员在生物反应器中描述了一种在没有氧气和硝酸盐/亚硝酸盐的情况下与铁还原偶联的铵氧化新途径，并被称为Feammox。进一步的研究已经在新泽西州湿地沉积物的培养物中进行，证实Feammox是一个生物过程，并且以前未知的酸微生物科细菌A6负责它。样品已经富集，PI已经分离出纯的酸微生物科细菌A6菌株。从增加缺氧生物反应器与水铁矿和Acidimicrobiaceae细菌A6的初步结果表明，有一个潜在的利用这一过程的厌氧生物氨氧化。已经分离出的Acidimicrobiaceae细菌A6提高了确定Feammox的功能基因的潜力，并获得了对这一过程及其应用的新的基本见解。几乎所有的废水处理厂在发达国家以及许多发展中国家，在排放处理后的废水之前，都将氨氧化为硝酸根离子。这样做是为了减少受纳沃茨的需氧量。生物铵氧化是由好氧（在氧气存在下）硝化细菌进行的，需要曝气，这是污水处理厂中能量输入最高的步骤。一种替代方案是部分硝化+厌氧氨氧化系统，该系统在过去15年中已在一些处理厂实施，其目的是节省能源成本，因为只有一半的氨在有氧条件下转化为亚硝酸根离子，而其余的则通过厌氧氨氧化转化为氮气。然而，这些基于厌氧氨氧化物的废水处理系统需要在28至35摄氏度的温度下运行。相比之下，我们已经表明Feammox途径在低于10摄氏度时仍然活跃。因此，基于Feammox的工艺可以通过在温和气候下不需要对废水进行曝气或加热来进一步节省能源，尽管必须考虑Fe（III）源的成本。此外，近岸环境中的氮过量已被确定为导致富营养化和缺氧的主要环境问题（切萨皮克湾、墨西哥湾等）。因此，正在起草立法，要求在传统的废水处理厂中将硝酸盐转化为氮气。Feammox工艺可以在一段反应器中实现低能耗脱氮。

1433101JaffeA new pathway for ammonium oxidation coupled to iron reduction in the absence of oxygen and nitrate/nitrite has recently been described by the PI and co-workers for wetland soils in New Jersey, by researchers from UC Berkeley in tropical rainforest soils, and by researchers in Japan in a bioreactor, and has been referred to as Feammox. Further Studies have been conducted in incubations of NJ wetland sediments, confirming that Feammox is a biological process, and that an Acidimicrobiaceae bacterium A6, previously unknown, is responsible for it. Samples have been enriched and the PI has isolated the pure Acidimicrobiaceae bacterium A6 strain. Preliminary results from augmenting an anoxic bioreactor with ferrihydrite and Acidimicrobiaceae bacterium A6 have shown that there is a potential to exploit this process for anaerobic biological ammonium oxidation. Having isolated the Acidimicrobiaceae bacterium A6 raises the potential to determine the functional gene responsible for Feammox and to gain new fundamental insights into this process and its applications.Virtually all wastewater treatment plants in the developed world as well as in many developing countries oxidize ammonia to nitrate ion, before discharging the treated wastewater. This is done to decrease oxygen demand in the receiving waters. Biological ammonium oxidation is conduced by aerobic (in the presence of oxygen) nitrifying bacteria and requires aeration, the step with the highest energy input in wastewater treatment plants. An alternative is the partial nitrification + Anammox system, which has been implemented in some treatment plants over the past 15 years, with the goal of saving energy costs, since only half of the ammonia is converted to nitrite ion aerobically, while the rest is converted to nitrogen gas anaerobically via Anammox. However, these Anammox-based wastewater treatment systems need to operate at temperatures between 28 and 35 Celsius. In contrast, we have shown that the Feammox pathway is still active at below 10 Celsius. Hence, a Feammox-based process could result in further energy savings, by requiring no aeration or heating of the wastewater water in temperate climates, although the cost of an Fe(III) source will have to be taken into account. Furthermore, N excess in near-shore environments has been identified as a major environmental problem leading to eutrophication and anoxia (Chesapeake Bay, Gulf of Mexico, etc.). Therefore legislation is being drafted which will require conversion of nitrate to nitrogen gas in conventional wastewater treatment plants. Potentially the Feammox process could achieve N removal in a single stage reactor with low energy utilization.