First Advisor

William Fish

Date of Award

Spring 2014

Document Type



Civil and Environmental Engineering




Landfill gases -- Recycling -- Oregon, Sanitary landfills -- Environmental aspects, Sanitary landfills -- Management, Anaerobic bacteria -- Research




Cities around the world transport large quantities of waste to landfills at a great expense to their residents, infrastructures, and environments. The objective of this study was to run an anaerobic food waste digester with minimal interference or maintenance. One specific goal of this research was to evaluate the relationship between anaerobic food waste and pH. Two benchop digesters were started with vegetarian food waste collected from the Portland State University campus. Measurements were collected over the course of the digestion process. Due to low pH and lack of biogas production, the digesters were buffered with sodium carbonate and seeded with wastewater digestate. Post recovery, the solids content decreased and methane production began though the process was never fully optimized. The lack of digester performance is thought to be due in part to low operation temperature.


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A thesis submitted in partial fulfillment of the requirement for the degree of Bachelor of Science with Departmental Honors in Civil and Environmental Engineering.

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