Northwestern Events Calendar

Dec
7
2018

EES Seminar: Konrad Koch

When: Friday, December 7, 2018
2:00 PM - 3:00 PM CT

Where: Technological Institute, A230, 2145 Sheridan Road, Evanston, IL 60208 map it

Audience: Faculty/Staff - Student - Public - Post Docs/Docs - Graduate Students

Contact: Tierney Acott   (847) 491-3257

Group: McCormick - Civil and Environmental Engineering (CEE)

Category: Lectures & Meetings

Description:

Improving the Efficiency of Anaerobic Digestion Processes

Abstract

Wastewater treatment plants are currently still the largest municipal consumers of electricity, although wastewater contains more than enough energy required for its purification. While treatment of wastewater under the given limits for discharge still has the highest priority, there are some approaches for both to reduce the energy required for the treatment and to recover more energy from it.
Elemental for this is the determination of the biomethane potential, which is usually done by means of anaerobic batch tests. Unfortunately, round robin tests repeatedly showed that the procedure has not yet been sufficiently standardized or there are too many influencing factors that can falsify the results. By means of systematic studies and joint discussions, the standardization of batch tests should be further advanced.
An increase in efficiency in the conversion of hardly degradable substrates is exemplarily possible by a pretreatment with ultrasound. The investigations have shown that besides the increased methane yield also other effects should be considered. For a holistic assessment, also a possibly improved dewaterability, a reduced amount of biosolids for disposal, and effects on sludge rheology and foaming tendency have to be taken into account.
The addition of co-substrates into the existing sludge digestion can also significantly increase the biogas yield. The sensible use of existing infrastructure and often described synergy effects by the mixture of substrates with different properties are faced with challenges in substrate pretreatment and storage, an potentially increased amount of residues for disposal and a possible backload of the wastewater treatment plant with nitrogen-rich centrate from sludge dewatering.
The latter can also be treated via deammonification in side stream as an alternative to the robust but energy-intensive process of nitrification/denitrification. This requires clearly less energy for aeration and even completely dispenses with the use of a carbon source through an autotrophic process. However, the comparatively low energy gain for the microorganisms involved also requires tight process monitoring and control.
There is even the possibility of at least partially recovering the energy bound in the ammonium from the wastewater. It also uses a nitritation (conversion of ammonium into nitrite) as a first stage, but then switches to a denitritation, in which intentionally nitrous oxide is generated with the addition of a carbon source. However, this novel process is still under investigation and still quite some challenges have to be tackled.
Finally, wastewater treatment plants can also contribute to the energy transition by applying microbiological methanation. Excess electricity from renewable sources can first be converted into hydrogen by means of an electrolyzer and then together with CO2 into methane to be stored. Biofilm-based technologies under thermophilic conditions have proven to be suitable particularly under dynamic operation.

Biography

Konrad Koch studied “Waste management and contaminated site treatment” at the Dresden and the Hamburg University of Technology, where he completed his diploma thesis in 2007. His PhD at the Institute of Water Quality Control at TUM was dedicated to the modeling of the anaerobic digestion of energy crops, which he finished in 2010. Between 2010 and 2012 he was the head of a research group at the Institute of Agricultural Engineering and Animal Husbandry of the Bavarian State Research Center for Agriculture in Freising, Germany.
Since 2012 he is assistant professor at the Chair of Urban Water Systems Engineering at TUM, where he mastermind several projects focusing on energy recovery from waste and wastewater streams with special emphasize on enhancing understanding, optimization of the process, and development of approaches for process monitoring and modeling.

 

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