Date of Award:

5-1-2011

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biological and Irrigation Engineering

Advisor/Chair:

Ronald Sims

Abstract

Excess nitrogen and phosphorus in discharged wastewaters can lead to downstream eutrophication, ecosystem damage, and impaired water quality that may affect human health. Chemical-based and physical-based technologies are available to remove these nutrients; however, they often consume significant amounts of energy and chemicals, greatly increasing treatment costs. Algae are capable of removing these pollutants through biomass assimilation, and if harvested, can be utilized as a feedstock for biomethane or biodiesel production. Currently, difficulties in harvesting, concentrating, and dewatering algae have limited the development of an economically feasible treatment and production process. When algae are grown as surface-attached biofilms, the biomass is naturally concentrated and more easily harvested, leading to less expensive removal from treated water, and less expensive downstream processing for biofuel production. In this study, a novel algal biofilm production and harvesting system was designed, built, and tested. Key growth parameters were optimized in order to maximize biomass production and nutrient uptake from wastewater. Compared to suspended algae systems, the attached algal biofilm design of this study led to increased biomass production and greater treatment of domestic wastewater. An efficient and inexpensive algal biofilm harvesting technique was also developed in order to obtain a concentrated biosolids product, resulting in improved water quality and a feedstock suitable for further processing in the production of biofuels.

Comments

This work made publicly available electronically on August 9, 2011.

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