Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Biological Engineering

Committee Chair(s)

Ronald C. Sims


Ronald C. Sims


Jon Y. Takemoto


Judith L. Sims


Due to population expiation and the increased awareness of the impact on the environment by wastewater treatment, improved wastewater treatment systems are needed to treat municipal and agricultural wastewater. Treating wastewater with oxygen decreases carbon compounds at the expense of energy to move carbon and oxygen to be in contact with each other. Anaerobic digestion of wastewater can reduce the cost by utilizing microbes to treat high amounts of carbon in wastewater without the need for extensive oxygen requirement. With a proper balance of nutrients, microbes also produce methane, a renewable energy source.

It has been suggested that microalgae be utilized to help balance the nitrogen content of wastewater for treatment by microbes. One challenge with the use of algae is the initial breakdown of algae cells. Using a digester with microorganism that can produce methane and decompose algae could enhance production of methane from the digestion of algae. The combination of wastewater, which is high in carbon content relative to nitrogen, with algae, which is high in nitrogen, could provide the balance needed for the microbes to treat wastewater and provide methane.

A biomethane potential test was used to compare the ability of two microbe communities, facultative lagoon sediment and anaerobic digester sludge to digest algae. Each microbe community treated dairy, swine, municipal, and petrochemical wastewater augmented with algae and acetate. The ability to degrade augmented wastewater and produce methane was determined by measuring the volume and composition of biogas produced over time. Both treatments were successful in production of methane. Facultative lagoon sediment showed more methane produced per carbon dioxide than anaerobic digester sludge.