Pollution

Event Date: 
Wednesday, February 25, 2015 - 15:30 - 16:00
Institution: 
University of California Davis
Title: 

Stress, function and community dynamics in wastewater bioreactors

Abstract: 

Biological wastewater treatment plants receive a complex mixture of chemicals and are operated based on principles of general microbial growth kinetics. Regulated effluent criteria determine the extent of treatment required to achieve removal of chemical oxygen demand and nutrients like reduced nitrogen and phophate. Plants are, however, not designed to metabolize specific (micro)pollutants, and the factors influencing the emergence of microbial communities that are tolerant of or have evolved to metabolize and remove toxic compounds are poorly understood. Basic questions in wastewater engineering include ‘What affects the dynamics of wastewater microbial communities?’  and ‘Are communities ever stable and if so does this matter for basic processes like removal of organics and nutrients?’.  
We investigated the impact of defined and sustained chemical stress on wastewater microbial communities and their functions, using the highly toxic and recalcitrant compound 3-chloroaniline (3-CA) as model stressor. Experimental design included replicate bioreactors, sterile synthetic feed, ambient levels of 3-CA, and fixed factors like bioaugmentation and temperature. Process outcomes varied from no removal of 3-CA to complete removal within three weeks. Community changes were dramatic and nitrification was a key function affected by the stressor. Finally, microbial diversity indices based on 16S rRNA gene amplicon sequencing or T-RFLP, combined with influent nutrient concentrations, were used to predict effluent concentrations using support vector regression, a machine learning model. Sensitivity analysis of a preliminary dataset for a full-scale water reclamation plant would suggest that evenness is the most significant input variable for the prediction of soluble COD, nitrate and ammonium concentrations in the effluent. Overall, we show that both detailed analysis of taxonomy and gene expression and general indices of diversity are useful for understanding the link between stable process performance and microbial communities.

Event Date: 
Wednesday, September 25, 2013 - 07:00 - 08:00
Institution: 
Helmholtz Centre for Groundwater Ecology, Munich, Germany
Title: 

Limiting factors for anaerobic aromatic hydrocarbon degradation in contaminated aquifers and oil reservoirs

Abstract: 

 
Biography

  • Rainer Meckenstock studied biology at University of Konstanz, Germany 1985-1990. He finished with a thesis in the group of Prof. Winfried Boss on microbial sugar transport systems (molecular microbiology). He did his PhD at the Swiss Federal Institute of Technology (ETH) in Zürich, Switzerland, with a thesis on biochemistry of light-harvesting complexes of phototrophic bacteria (1990-1993) in the Institute of Molecular Biology and Biophysics with Prof. Zuber. During his post-doc at the Swiss Federal Institute of Environmental Science andTechnology (EAWAG) in the group of Dr. van der Meer in Dübendorf, Switzerland, he developed molecular methods to monitor trichlorobenzene-degrading microorganisms and their degradation activities in the environment (PCR, RT/PCR, in situ hybridisation) (1993-1995). He changed to the investigation of anaerobic degradation of aromatic hydrocarbons in the Microbial Ecology Group of Prof. Bernhard Schink, University of Konstanz, Germany, in 1996. Here, he isolated novel anaerobic BTEX and PAH-degrading organisms and studied the degradation pathways. A new method to study microbial activities in the environment with analysis of stable isotope fractionation was developed. Since 2000 he changed to the Center of Applied Geosciences at the University of Tübingen, Germany, and set up a Geomicrobiology group within the Chair of Environmental Mineralogy (Prof. Stefan Haderlein). Research topics were the anaerobic degradation of mono- and polycyclic aromatic hydrocarbons (BTEX, PAH), isotope fractionation as a means to monitor biodegradation in contaminated groundwaters, limitations of natural attentuation, and the reduction of iron minerals as electron acceptor. Since July 2003, he became the director of the Institute of Hydrology at GSF which changed its name to Institute of Groundwater Ecology at the beginning of 2004. In 2007 he was appointed as a full professor for Groundwater Ecology at the Life Science Center (WZW) of the Technical University of Munich.
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