Date of Award

3-10-2010

Document Type

Thesis

Degree Name

Master of Science in Environmental Engineering and Science

Department

Department of Systems Engineering and Management

First Advisor

Charles Bleckmann, PhD

Abstract

The micro-alga Chlorella vulgaris was cultivated under a variety of environmental conditions in various culture media solutions to assess and optimize growth rate and biomass productivity. Efforts during this work investigated growth parameters at the micro-scale in an air-lift bubble system with the goal of interpreting performance characteristics that can be applied to a larger serpentine tubular Photo-bioreactor. Maximum growth rates and biomass yields were 0.65 d-1 and 2.003 g biomass/L and achieved in seven days using urea in de-ionized water under a 24:0 Photoperiod (Light:Dark). Additionally, growth rates and biomass yields of 0.65 d-1 and 1.964 g biomass/L were achieved over the same time period using commercial fertilizers in Charcoal Filtered Tap Water, indicating that the alga is very robust and tolerant of a wide range of environmental conditions, including nutrient composition and water type. CO2 tolerance was investigated to determine the utility of the alga in power plant flue gas remediation schemes. The alga grew in all CO2-in-Air concentrations between ambient air and 50% CO2 with maximum growth occurring at concentrations between ambient levels and 20% CO2-in-Air. However, reductions in growth rate and biomass yield were observed at CO2-in-Air concentrations between 20% and 50%, indicating some level of pH induced toxicity. Greatest growth was observed in the culture grown on 15% CO2-in-Air, indicating this particular alga may be appropriate for power plant flue gas remediation (13-16% CO2 in flue gas).

AFIT Designator

AFIT-GES-ENV-10-M03

DTIC Accession Number

ADA515174

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