Engineering Commons^™

Effect Of Low Aeration And Heat Drying On Anaerobic Digester Performance And Microbial Community, Dylan Thomas Friss

Master's Theses (2009 -)

This thesis describes three research projects on anaerobic digestion (AD) that investigated functional differences and relationships between microbial composition and digester function. Both archaeal and bacterial communities were characterized using high throughput (Illumina) sequencing technology with universal 16S rRNA gene primers. In the first project, limited aeration, and limited aeration with an aerotolerant enrichment culture were investigated as possible methods to increase digester functional performance in comparison to a strictly anaerobic control digester. No functional differences were observed at quasi-steady state between the limited aerated digester (LAD), limited aerated anaerobic digester augmented with an aerotolerant enrichment culture (LADE), and strictly …

Bioaugmentation And Correlating Anaerobic Digester Microbial Community To Process Function, Kaushik Venkiteshwaran

Dissertations (1934 -)

This dissertation describes two research projects on anaerobic digestion (AD) that investigated the relationship between microbial community structure and digester function. Both archaeal and bacterial communities were characterized using high-throughput (Illumina) sequencing technology with universal 16S rRNA gene primers. In the first project, bioaugmentation using a methanogenic, aerotolerant propionate enrichment culture was investigated as a possible method to increase digester methane production. Nine anaerobic digesters, seeded with different biomass, were operated identically and their quasi steady state function was compared. Before bioaugmentation, different seed biomass resulted in different quasi steady state function, with digesters clustering into high, medium or low …

Preservation Of Methanogenic Cultures To Enhance Anaerobic Digestion, Ujwal H. Bhattad

Dissertations (1934 -)

The use of anaerobic biotechnology is increasing as a sustainable process to treat various organic wastes. Methanogens convert organic COD into CH4 and play the key role to drive thermodynamically unfavorable biochemical fermentation reactions and keep the digestion process steady and efficient. Progressive understanding of anaerobic microbiology with digester functionality may help to develop efficient, customized methanogenic cultures to enhance anaerobic bioprocesses. Preservation of methanogenic cultures via drying would be a cost-effective option for research and practical applications. However, preservation of methanogenic cultures is challenging due to methanogen sensitivity to O2 toxicity and drying, and very limited work is reported …

Relating Methanogen Community Structure And Function In Anaerobic Digesters, Benjamin T.W. Bocher

Dissertations (1934 -)

A deeper understanding of how microbial community structure relates to process function would help improve anaerobic digester design. This dissertation describes both qualitative and quantitative relationships between anaerobic digester function and microbial community structure. Community structure was characterized using banding pattern intensities from denaturing gradient gel electrophoresis (DGGE) for the mcrA gene of methanogenic Archaea. The first project compared a single-stage continuously mixed stirred tank reactor (CSTR) and staging with an acidogenic CSTR followed by a methanogenic CSTR. After seeding with the same biomass, these unique process configurations exhibited different function and qualitatively different methanogen communities. Compared to a single-stage …

Bioaugmentation For Recovery Of Anaerobic Digesters Subjected To Organic Overload, Vaibhav Panjabrao Tale

Dissertations (1934 -)

Anaerobic digester upset due to organic overload is common and methods to reduce recovery time would be beneficial. One potential method is bioaugmentation, the addition of an external culture for performance improvement. Methanogenic community structure differs from digester to digester and there may exist a relation between specific methanogenic activity (SMA) and microbial community composition. The research presented herein tested whether there is a relationship between SMA and community structure. Also, the effectiveness of bioaugmentation was tested by hypothesizing that bioaugmenting with a methanogenic, propionate-degrading culture acclimated to small oxygen doses will help rapid recovery of organically overloaded digesters.

Fourteen …