ECO-CBET: Modular Electrochemical Processes for Simultaneous Nitrogen Recovery and Carbon Dioxide Mitigation

畜牧业是农业的一个重要分支，为人类提供富含蛋白质的食品。然而，反刍动物系统产生大量的温室气体排放，并可能产生有害的环境影响。这种畜牧系统越来越受到压力，要求变得更加具有环境可持续性。许多环境问题源于牲畜粪便成分的释放，包括营养物质，病原体和有机物质，进入环境。这些排放污染地表和地下沃茨，增加气候变化的风险，产生令人讨厌的气味，并最终对人类和动物健康构成威胁。此外，粪肥的高含水量和低养分密度增加了运输到农田的成本，限制了其有效利用。从粪肥中回收养分可以改善养分管理，并将负面环境影响的可能性降至最低。通过将粪肥加工产生的沼气中的二氧化碳转化为燃料和其他有用产品，可以进一步减轻气候影响。该项目是威斯康星大学麦迪逊分校和马萨诸塞州理工学院的研究人员之间的合作，旨在通过开发新型模块化电化学过程来克服粪便处理系统面临的挑战。拟议的系统将整合电化学过程，同时从牲畜粪便中回收氨作为肥料，并将二氧化碳转化为当地有价值的化学品。从这项研究中产生的知识将满足对可持续和有效的牲畜粪便管理日益增长的需求。该团队将让K-12，本科生和研究生参与STEM推广和研究经验。确定为STEM中代表性不足的群体成员的学生将通过与校园组织的合作伙伴关系进行招募和指导。通过对农民、政策制定者、农业教育工作者和公众的宣传和教育活动，也将为社会带来好处。牲畜粪便会使营养物质、病原体和有机物流失到环境中，降低地表水和地下水的质量，加剧气候变化，并造成人类和动物的健康问题。处理粪肥以回收嵌入的养分可以通过增加养分密度来减轻这些影响，使肥料更易于管理，可以经济地运输到偏远地区。该ECO-CBET项目的总体目标是开发模块化电化学工艺，通过回收氨作为肥料，增加养分密度，并从二氧化碳中生产有价值的化学品供现场应用，来解决牲畜粪便系统中的碳、养分和水挑战。这些电化学过程通过氧化还原储库而独特地实现，所述氧化还原储库可逆地存储电子和特定离子，同时用作可互换的反电极，用于与互补的电化学半反应灵活集成。富铵粪肥废水可以被进料到具有生物电化学阳极和氧化还原池阴极的原电池中，其选择性地从环境中提取铵阳离子。氧化还原储层被引入电解池中，在电解池中，氧化还原储层用作阳极，释放铵，并与二氧化碳还原阴极配对，用于共同生成有用的产品，包括甲酸，补充动物饲料防腐剂，和甲烷，可注入天然气管道的可再生原料。具体目标是：1）开发牲畜粪便的预处理，合成和表征新的氧化还原储层材料，并证明氧化还原储层启用的从粪便中选择性氨回收的可行性; 2）将氨回收与二氧化碳转化为模块化系统中的增值产品;以及3）对单个和组合模块化系统进行技术经济和生命周期分析。该项目的成功将为更有效地从粪肥中回收养分和碳资源引入变革性概念，为分布式和可持续的化学制造提供新的见解，培养下一代跨学科科学家和工程师，并在农民，政策制定者，农业教育者，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Livestock farming is an essential branch of agriculture that provides protein-rich food products to humans. However, ruminant animal systems produce substantial amounts of greenhouse gas emissions and can have deleterious environmental impacts. Such livestock systems are increasingly under pressure to become more environmentally sustainable. Many of the environmental issues stem from the release of livestock manure constituents, including nutrients, pathogens, and organic matter, into the environment. These releases contaminate surface and ground waters, increase the risk of climate change, cause nuisance odors, and, ultimately, pose a threat to human and animal health. In addition, manure’s high water content and low nutrient density increase the transportation cost to farmlands and limit its effective use. Recovering nutrients from manure can improve nutrient management and minimize the possibility of negative environmental impacts. Climate impacts could be further mitigated by converting the carbon dioxide in the biogas generated from manure processing into fuels and other useful products. This project, a collaboration between investigators at the University of Wisconsin–Madison and Massachusetts Institute of Technology, seeks to overcome the challenges facing manure processing systems through the development of novel modular electrochemical processes. The proposed system will integrate electrochemical processes to simultaneously recover ammonia from livestock manure as fertilizer and convert carbon dioxide to locally-valuable chemicals. The knowledge generated from this research will address the growing need for sustainable and effective livestock manure management. The team will engage K-12, undergraduate, and graduate students in STEM outreach and research experiences. Students identifying as a member of an underrepresented group in STEM will be recruited and mentored through partnerships with on-campus organizations. Benefits to society will also be achieved through outreach and education activities for farmers, policymakers, agriculture educators, and the general public.Livestock manure can lose nutrients, pathogens, and organic matter to the environment, degrading both surface and ground water quality, contributing to climate change, and creating human and animal health issues. Processing manure to recover embedded nutrients can mitigate these impacts by increasing nutrient density, making a more manageable fertilizer that can be economically transported to remote locations. The overall goal of this ECO-CBET project is to develop modular electrochemical processes to tackle carbon, nutrient, and water challenges in livestock manure systems by recovering ammonia as fertilizers with increased nutrient density and producing valuable chemicals from carbon dioxide for on-site application. These electrochemical processes are uniquely enabled by redox reservoirs, which reversibly store electrons and specific ions while serving as interchangeable counter electrodes for flexible integration with complementary electrochemical half-reactions. The ammonium-rich manure wastewater can be fed into a galvanic cell with a bioelectrochemical anode and a redox reservoir cathode that selectively extracts ammonium cations from the milieu. The redox reservoir is introduced into an electrolytic cell, where it serves as an anode, releasing ammonium, and is paired with a carbon dioxide-reducing cathode for co-generation of useful products, including formic acid, a supplemental animal feed preservative, and methane, a renewable feedstock that can be injected into natural gas pipelines. The specific objectives are: 1) develop the pretreatment of livestock manure, synthesize and characterize new redox reservoir materials, and demonstrate the feasibility of redox reservoir-enabled selective ammonia recovery from manure; 2) integrate ammonia recovery with carbon dioxide conversion to value-added products in modular systems; and 3) perform techno-economic and life cycle analyses of individual and combined modular systems. The success of this project will introduce transformative concepts for more efficient nutrient and carbon resource recovery from manure, generate new insights for distributed and sustainable chemical manufacturing, train the next generation of interdisciplinary scientists and engineers, and provide exciting STEM outreach and education opportunities at the intersection of the farmers, policymakers, agriculture educators, and the public.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.