Presenter: Margery Price – Earth Sciences
Faculty Mentor(s): Thomas Giachetti
Session: (In-Person) Poster Presentation
Graywater (wastewater produced by bathing, washing, and other domestic water uses) contains particles that can be removed by filtration. With treatment, it can be reused for tasks such as irrigation or street cleaning. Pumice and scoria, highly porous volcanic rocks, are optimal filtration media; they have both high external and internal surface area due to their tortuous networks of connected pores. This project investigates the physical characteristics of pumices and scoriae that most impact their efficacy as filter materials by testing interactions between the rocks and graywater. Samples of pumice and scoria from Oregon volcanoes are measured using a Particle Analyzer, a high precision scale, and a helium pycnometer to find mass, volume, packing fraction, and total and connected porosity. Graywater is created using conventional household cleaning and personal care products, then characterized for pH, turbidity, TDS, and conductivity. Lastly, static absorption experiments examine the interactions between pumice and scoria with both tap water and graywater when submerged. Preliminary results show that pumice and scoria systems of the same sizes absorb similar volumes of water, despite having different porosities. Scoria offers more area of interaction with water on its external surfaces, but pumice contains more available surface area within the particles. More work needs to be done investigating which of these parameters results in better filtration of graywater.