Ecological Engineering for Optimal Management of Agricultural and Municipal Organic Residues

克拉克的生态工程研究小组对提供服务或解决方案的生态系统的创建和管理进行了创新研究。该小组同时使用计算建模和物理实验。他们最近在容器内堆肥方面的工作导致了关于堆肥生产和利用的行业和市政研究伙伴关系。相关工作调查了大规模养分循环模型和区域农业系统综合评估模型的可行性。该小组目前在研究人类主导的生态系统中的养分流动方面处于有利地位。在工业化经济体中，农作物的主要营养物质是不可持续的来源。氮肥是从大气中固定下来的，耗费巨大的能源成本，而磷肥和钾肥是从不可再生的矿藏中提取的。这些养分被应用于农田，作为食品供应链的一部分集中在城市，然后分散在环境中。挑战正在增加，因为到本世纪中叶，不断增长的人口和富裕程度将使粮食需求翻一番。与此同时，能源成本的上涨和矿产资源的枯竭将使化肥变得更加昂贵。随着全球城市化的继续，这些营养物质越来越集中在不断增长的城市中。粮食和生物质生产的长期可持续性要求通过对废物管理系统的颠覆性、大规模的改造，将养分循环用于生产。在短期内，该小组先前的经验强烈地表明他们将推进：(1)多尺度物质和能量流动的计算模型，以及(2)有机残留物的回收。第一个研究重点将集中在物质和能量流动的多尺度模拟上。这项工作将扩展城市新陈代谢的概念，描述养分从农田到城市和环境的运输。然后将评估废物管理系统的颠覆性变化战略，转而将养分循环用于农业生产。对有机残渣进行大规模堆肥等技术可以将回收的养分带回传统的农地或城市农业倡议。这项工作将在博士和研究助理水平上进行，通过与克拉克的政府、行业和学术同事进行强有力的跨学科合作。第二个研究重点是堆肥生产的物理和计算模型，以回收有机残留物。这项工作对于评估作为大型系统模型的一部分而提出的技术是必要的。克拉克团队的初步工作显示，在堆肥中添加生物炭以减少气体排放和保留氮气是有希望的。新的工作将优化新型生物聚合物在堆肥中的降解。重复的物理实验将在现有的Pilo规模的堆肥容器中进行，这些容器配备了自动测量温度和气体排放的仪器。这项工作将是实验室小组理学硕士工作的主要重点。这些共同努力将提升该小组的综合专业知识，为基于合理管理地球有限生物资源的可持续经济发展做出更大贡献。在更大的范围内，这项工作将为区域和国家的粮食和生物质可持续生产政策提供信息。这项工作将在中期为制定有机物回收标准和协议做出贡献，因为许多市政当局都在争先恐后地实施回收和堆肥计划。在规模较小的情况下，堆肥技术和利用方面的创新将使集团的工业和市政合作伙伴受益。

Clark’s Ecological Engineering Research Group has performed innovative research on the creation and management of ecosystems that provide services or solutions. The group uses computational modeling and physical experimentation in parallel. Their recent work on in-vessel composting has led to industry and municipal research partnerships on compost production and utilization. Related work investigated models of large-scale nutrient cycling and on the feasibility of Integrated Assessment Modeling of regional agricultural systems.The group is now strongly positioned to study the flow of nutrients through human-dominated ecosystems. In industrialized economies, the principle crop nutrients are unsustainably sourced. Nitrogen fertilizer is fixed from the atmosphere at a huge energy cost and phosphorous and potassium fertilizers are extracted from nonrenewable mineral deposits. These nutrients are applied to agricultural land, concentrated in cities as part of the food supply chain, and then dispersed in the environment. The challenges are increasing, as growing population and affluence will double demand for food by midcentury. At the same time, rising energy costs and depletion of mineral resources will make fertilizers more expensive. These nutrients are increasingly concentrated in growing cities as urbanization continues worldwide. Long-term sustainability of food and biomass production demands that nutrients be recycled back to production, by the disruptive, large-scale reinvention of waste management systems.In the short term, the group’s prior experience strongly positions them to advance: (1) computational modeling of multi-scale material and energy flows, and (2) the recycling of organic residues. The first research thrust will focus on multi-scale simulation of material and energy flows. The work will expand on the concept of urban metabolism, characterizing nutrient transport from agricultural land, to cities, and into the environment. Strategies will then be evaluated for disruptive change in waste management systems, to instead recycle nutrients back to agricultural production. Technologies such as large-scale composting of organic residuals could direct reclaimed nutrients back to traditional agricultural land or to urban agriculture initiatives. This work will be conducted at the doctoral and research associate level, through strong interdisciplinary collaboration with Clark’s government, industry, and academic colleagues.The second research thrust is the physical and computational modeling of compost production to recycle organic residues. This work is necessary to evaluate technologies proposed as part of the large-scale systems models. Preliminary work by Clark’s group shows promise in adding biochar to compost to reduce gas emissions and retain nitrogen. New work will optimize the degradation in compost of novel biopolymers. Replicated physical experiments will be run in existing pilo-scale composting vessels, instrumented for automated measurement of temperature and gas emissions. This work will be the primary focus of the MSc stream of the lab group.These combined efforts will elevate the group’s combined expertise to make even greater contributions to the development of a sustainable economy based on the rational management of the planet’s finite biological resources. On a large horizon, the work will inform regional and national policy for the sustainable production of food and biomass. The work will contribute in the mid-term to the development of standards and protocols for organics recycling, as many municipalities scramble to implement recycling and composting programs. At a smaller scale, innovation in composting technology and utilization will benefit the group’s industrial and municipal partners.