<p>This work presents an improved aggregation model that accounts for two types of particles and simulates the heterogeneous aggregation between these particles. By accounting for the sizes, concentrations, and affinities of the nano- and background particles, the model can evaluate e.g. how the nanoparticles affect an existing distribution of natural aggregates or how quickly the nanoparticles will settle out of a given system, and can help determine which parameter to change in order to eliminate the nanoparticles from a system faster. The model could provide a powerful tool to evaluate the exposure of nanoparticles in environmental and engineered waters.</p> / Dissertation