The nutrient microgrid: Ecologically-inspired design of urban material cycling networks

Abstract

Engineered systems are composed of multiple interconnected networks that produce, process, and dispose of waste materials. However, to achieve process efficiency within system boundaries, engineers have historically designed supply chains that are highly centralized and modeled them with surroundings of infinite material sources and sinks. Considering the dwindling resources and growing pollution brought on by this design strategy, this thesis focusses on the material dynamics of the human food supply and waste management infrastructure to identify possible improvements to the material efficiency of these engineered systems. Case studies tracing material through selected urban and industrial networks are presented, and emerging biotechnologies, including aquaponics and constructed wetlands among others, are then introduced to these networks as material cycling modules. These reimagined material networks are then analyzed using ecological and sustainability metrics and compared to the original networks to assess impact and efficiency. Results suggest that a design strategy that employs higher degrees of nutrient cycling, catalyzed by ecologically-inspired material cycling modules, can improve material efficiency and increase the resilience of these systems. Results also suggest that a decentralized urban agriculture network may be more fragile to disruption, with highly specific food sourcing and confined flow paths that do not allow for restructuring in the event of a perturbation.