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Gewählte Doctoral Thesis:

Maren Mellendorf (2011): Characterisation of microbial communities during in-situ aeration of landfill material.
Doctoral Thesis - Institut für Bodenforschung (IBF), BOKU-Universität für Bodenkultur, pp 158. UB BOKU obvsg

Abstract:

In-situ aeration of old landfills is one option to reduce long term emissions through the conversion of biodegradable organic compounds, organic matter degradation and biological stabilization by low pressure air injection. Studies about the microbiology of landfills and waste material under in- situ aeration are sparse. The heterogeneity of waste material and differences in environmental parameters influencing microbial biomass, composition and activity are the main challenges for qualitative and quantitative microbial in-situ aeration studies. This thesis characterizes anaerobic and aerobic microbial community compositions and dynamics in field-scale and laboratory column experiments during in- situ aeration and statistically related to physical- chemical parameters. Simplifying the microbial dynamics, three phases were proposed (i) anaerobic, (ii) aeration start and (iii) extended aeration conditions showing significant differences in microbial compositions. Anaerobic microbial groups were immediately affected by aeration, while sulphate- reducing bacteria decreased and Gram positive bacterial groups consecutive increased along with a rapid reduction of organics. Regardless of differences in physical- (bio) chemical waste characteristics, principal component analysis (PCA) revealed that in- situ aeration start triggered a similar increase of some Gram positive bacterial and ubiquitous microbial groups and the absence of sulphate- reducing bacteria and methanogenic archaea. Investigation of overall microbial communities in the field-scale approach were rather descriptive allowing an insight into the overall microbial composition within the limitations of environmental and analytical conditions. Leachate analysis showed tendencies for higher microbial biomass (revealed with lipid- based approaches) under in-situ aeration, a change in the fungal- to- bacterial ratio but also the abundance of anaerobic groups throughout the experimental time, solid waste analysis showed no obvious tendency related to in- situ aeration.

Betreuer: Gerzabek Martin