Trash: a local solution to a global problem

Gemstone Team GREEN JUSTICE

The Architecture of Waste: Creating New Avenues for Public Engagement with Trash

The relationship between industry, waste, and urbanism is one fraught with problems across the United States and in particular American cities. The interrelated nature of these systems of flows is in critical need of re-evaluation. This thesis critiques the system of Municipal Solid Waste Management as it currently exists in American cities as a necessary yet undesirable ‘invisible infrastructure’. Industry and waste environments have been pushed to the periphery of urban environments, severing the relationship between the urban environment we inhabit and the one that is required to support the way we live. The flow of garbage from cities of high density to landscapes of waste has created a model of valuing waste as a linear system that separates input from output. This thesis aims to investigate ways that industry, waste, and urban ecologies can work to reinforce one another. The goal of this thesis is to repair the physical and mental separation of waste and public activity through architecture. This thesis will propose ways to tie urban waste infrastructure and public amenities together through the merging of architecture and landscape to create new avenues for public engagement with waste processes.

GEOTECHNICAL AND ENVIRONMENTAL IMPACTS OF STEEL SLAG IN EMBANKMENTS

Steel slag is a byproduct of iron and steel production by the metallurgical industries. Annually, 21 million tons of steel slag is produced in the United States. Most of the slag is landfilled, which represents a significant economic loss and a waste of valuable land space. Steel slag has great potential for the construction of highway embankments; however, its use has been limited due to its high swelling potential and alkalinity. The swelling potential of steel slags may lead to deterioration of the structural stability of highways, and high alkalinity poses an environmental challenge as it affects the leaching behavior of trace metals. This study seeks a methodology that promotes the use of steel slag in highway embankments by minimizing these two main disadvantages. Accelerated swelling tests were conducted to evaluate the swelling behavior of pure steel slag and water treatment residual (WTR) treated steel slag, where WTR is an alum-rich by-product of drinking water treatment plants. Sequential batch tests and column leach tests, as well as two different numerical analyses, UMDSurf and WiscLEACH, were carried out to check the environmental suitability of the methods. Tests were conducted to study the effect of a common borrow fill material that encapsulated the slag in the embankment and the effects of two subgrade soils on the chemical properties of slag leachate. The results indicated that an increase in WTR content in the steel slag-WTR mixtures yields a decrease in pH and most of the leached metal concentrations, except aluminum. The change in the levels of pH, after passing through encapsulation and subgrade, depends on the natural pHs of materials.