Part III: Integrated Bio-Systems

Our paper analyzes the strengths and weaknesses of a subfield of industrial ecology called integrated bio-systems (IBS). Consistent with the principles of industrial ecology, the goal of an IBS is to reduce pollution by transforming linear material flows into closed, cyclical processes that produce value-added product. The presence of large, concentrated quantities of compost, generated as a residue during the mushroom growing process, creates an opportunity to develop innovative onfarm uses for this material. We consider two potential options: (1) a mushroom farm/mycorrhizae IBS; and (2) a mushroom/ biogas recovery IBS. INTRODUCTION Agriculture – the science, art, and business of soil cultivation, crop production, and animal husbandry – has evolved over time to meet the demands of a changing world. In general, population growth and rising demand for food has led to an intensification of agriculture characterized by increased use of capital and other inputs. This trend has increased the potential for “spillovers,” or material losses, and environmental degradation. Cyclical versus Linear Systems Traditional agricultural systems were cyclical in nature. For example, early agrarian societies would grow crops, raise livestock, and spread the livestock manure on fields to enhance crop production. Integration of these processes created a relatively closed, self-sustaining system based on principles of conservation of resources and limited wastes. The industrialization or “modernization” of agriculture over the last century, however, has been the main factor in transforming agriculture from a cyclical process to a linear process, through which large quantities of raw materials are consumed and large amounts of waste are emitted. Figure 1 illustrates this transformation (Allenby and Graedel 1995).