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模型和物理实验。他们最近在船内堆肥方面的工作导致了工业和市政在堆肥生产和利用方面的研究伙伴关系。相关工作研究了大规模养分循环模型和区域农业系统综合评价模型的可行性。该小组现在在研究人类主导的生态系统中营养物质的流动方面处于有利地位。在工业化经济体中，主要作物养分的来源是不可持续的。氮肥是从大气中固定下来的，需要耗费大量的能源，而磷肥和钾肥是从不可再生的矿藏中提取的。这些营养物质被用于农业用地，作为食品供应链的一部分集中在城市，然后分散在环境中。到本世纪中叶，随着人口和财富的增长，对粮食的需求将增加一倍，挑战正在增加。与此同时，能源成本的上升和矿产资源的枯竭将使化肥更加昂贵。随着全球城市化进程的继续，这些营养物质越来越集中在不断发展的城市中。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进行破坏性的大规模改造，将营养物质回收到生产中。在短期内，该小组先前的经验使他们能够推进：(1)多尺度材料和能量流的计算建模，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代谢的概念，表征从农田到城市和进入环境的营养运输。然后将评估各种战略，以便对废物管理系统进行破坏性的改变，从而将营养物质再循环到农业生产中。大规模有机残留物堆肥等技术可以将回收的营养物质引导回传统的农业用地或城市农业倡议。这项工作将在博士和研究助理水平上进行，通过与克拉克政府、行业和学术同事的跨学科合作。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规模系统模型的一部分提出的技术是必要的。克拉克小组的初步工作显示，在堆肥中添加生物炭以减少气体排放并保留氮是有希望的。新的研究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中试规模的堆肥容器中进行，并配有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硕士课程的主要重点。这些共同的努力将提升该集团的综合专业知识，为基于合理管理地球有限生物资源的可持续经济的发展做出更大的贡献。从长远来看，这项工作将为粮食和生物质可持续生产的区域和国家政策提供信息。随着许多城市争相实施回收和堆肥计划，这项工作将在中期为制定有机回收标准和协议做出贡献。在较小的范围内，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.