Relative environmental impacts of aqueous and solvent small parts cleaning systems: Application of life-cycle analysis methods to evaluate regulatory trends in the auto repair industrial sector.

摘要

Life cycle assessment is a tool well-suited to identifying and quantifying the resource requirements, environmental releases and impacts of a product or process. This research utilizes methods of life-cycle assessment to develop a comparison of the environmental impacts for solvent, aqueous, and bioremediative-aqueous small parts cleaning systems in the automotive repair industrial sector. The research demonstrates methods capable of identifying life-cycle impacts across multiple environmental media, with the purpose of facilitating informed policy decisions regarding substitution of one cleaning method over another. These methods are applied to auto repair facilities in the San Francisco Bay area, California, an industrial sector providing a ready example of multiple types of cleaning systems being used for similar purposes.; The research compiles a computational model defining the relationship among important unit processes in the life-cycle of the parts cleaning systems, and uses it to tabulate lifecycle materials and energy flows for the parts cleaner types. Sources of data used to populate the model range from first-hand site-specific data, to aggregate industrial data, to state and federal government pollutant emissions factors. This research evaluates the limitations of the life-cycle assessment, and evaluates how elements of the computational framework and research results are applicable to inquiries into other processes, or similar processes in different geographic regions.; In comparing the inventory and an extended set of life-cycle impacts at different impact levels, no one system was clearly preferable. For global level impacts the solvent system was favorable as its life-cycle generated the fewest greenhouse gas emissions. However, at the regional level the same solvent system is the most polluting in terms of VOCs, and it has the greatest potential of the three systems to adversely affect the user. Given the Bay Area's air pollution issues, results of this work support the current regulatory strategy of a wide-scale shift from solvent to aqueous cleaning methods. The most striking unintended first-order life-cycle impact of changing parts cleaning paradigms from solvent to aqueous was the increased electricity use of the aqueous parts cleaners during the cleaning phase, and the greater need for energy during the processing of aqueous waste. The LCA demonstrated its effectiveness for identifying this unintended effect. (Abstract shortened by UMI.)