Theses and Dissertations

Issuing Body

Mississippi State University


Truax, Dennis D.

Committee Member

Burcham, Tim

Committee Member

Zitta, Victor

Committee Member

Brown, Lewis

Committee Member

Magbanua, Benjamin

Date of Degree


Document Type

Dissertation - Open Access


Civil Engineering

Degree Name

Doctor of Philosophy


College of Engineering


Department of Civil Engineering


Confined animal feeding operations (CAFOs) relating to swine and their resulting odors continues to be an issue of concern. The primary sources of odors from a CAFO include general ventilation of the confinement house, the anaerobic lagoon, and the land application of lagoon sludge. This paper focuses on lagoon wastewaters, but the results therein could have influence on the other two aforementioned areas. An advanced upflow anaerobic/aerobic reactor system was developed to determine its impact on microbial activities that ultimately result in offensive odors. The microbial activity of SRB (sulfate-reducing bacteria) and hydrogen-sulfide production was monitored closely in each ?zone?, as well as other parameters such as dissolved oxygen and BOD. The results indicated a microbial physiology conducive to offensive odor production in the anaerobic zone of the pilot reactor and an aerobic microbial population in the upper zone of the pilot reactor. This aerobic zone was found to be effective in oxidizing the odorous gases created in the anaerobic zone. The overall microflora was consistent with an average magnitude of 108 CFU/mL. From the analysis performed, it was concluded that the microbiotic flora development and related substrate decomposition was the result of different metabolic pathways employed by the microflora rather than changes in the microbial population. In addition, the rise in pH throughout the experiment indicated the impact of the protein metabolic pathways (ammonification) over the carbohydrate metabolic pathways. Overall, the upflow anaerobic/aerobic pilot reactor proved to be an effective method for ?zoning? of the microbiotic flora, and a positive impact on the modifying the compounds related to offensive odor production.



swine||odor||hog||hydrogen sulfide||microbiology