Sustainability Decision Making for Renewable Biomass Energy Production: Integrated Algal Bio-energy and Environmental Remediation Systems

In this dissertation, a combination of life cycle modeling and laboratory experiments is used to evaluate the feasibility and sustainability of simultaneous biomass energy production and environmental remediation via the synergies of algal bioenergy generation and wastewater treatment polishing. Life cycle approaches include both life cycle assessment (LCA) and life cycle costing (LCC), for assessing environmental and economic performances, respectively, of integrated algae cultivation and dairy manure wastewater treatment on small dairy farms in the Southeastern US. Laboratory experiments are designed to evaluate algae-mediated removal of both environmental estrogens and the estrogenic toxicity they induce. The results indicate that the integrated systems will deliver not only algae-derived energy (as bio-electricity) but also water quality improvement, the latter via removal of aqueous nutrients (nitrogen and phosphorus) comprising eutrophication potential and also anthropogenic estrogenic compounds from wastewater. Additional work comprises expansion of the current LCA framework to include estrogenicity as an environmental impact category, and improvement of two LCA and LCC metrics; i.e., energy return on investment (EROI) and economic meta-model for algae bio-energy based on published LCCs. Results from this work will not only improve sustainability decision-making related to the proposed algae-to-energy systems, but also constitute methodological advancements to increase LCA’s usefulness during design of sustainable water-energy systems.