Mathematical Modeling of Carbon and Light-Limited Algal Biofilms

A mathematical model of carbon and light limitation in algal biofilms was developed based on well-established fundamental descriptions of chemical, physical, and biological processes. The model considers carbon dioxide utilization and production from photosynthesis and respiration, diffusion of inorganic carbon species, pH changes due to CO$\sb2$ utilization, mass transfer resistance due to a concentration boundary layer, light limitation, and photoinhibition. Because of the interaction of pH with the inorganic carbon system, inorganic carbon can easily become growth limiting within a biofilm, even when bulk carbon dioxide concentrations are very favorable. The concentration boundary layer had a significant adverse effect on biofilm growth which was enhanced by the inorganic carbon/pH interaction. Carbon limitation can be avoided by providing high inorganic carbon concentration. Light limitation, however, almost always occurs. Because of the inhibitory nature of high light intensity, higher light intensity does not necessarily improve growth. The interaction of carbon and light limitation in algal biofilms is very complex. The light intensity required to get the maximum growth rate depends on the availability and distribution of inorganic carbon. Algal biofilm reactors can be designed with either a front-lit or back-lit configuration. For high alkalinities, there is not much difference in maximum growth rate between the two configurations, although the front-lit configuration generally allows reasonably high growth rates over a much wider range of biofilm thicknesses. This modeling approach is a simplification of real systems, but is very useful for developing an understanding of the complex interactions that occur in algal biofilms.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Civil Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Liehr, Sarah Kate

Contributors dc:contributor

• Eheart, J. Wayland
• Suidan, Makram T.

• Biology, Ecology
• Engineering, Sanitary and Municipal
• Environmental Sciences

Language dc:language

eng

Identifier

(UMI)AAI8908754

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/77331