Researchers at the Leibniz Institute for Agricultural Engineering in Potsdam, Germany, have shown that anaerobic microorganisms can use complex organic pollutants for biogas production. Phenols, furans, aldehydes and ketones, which are frequently found in liquid by-products of thermochemical conversion of biomass, can easily and efficiently be degraded into bio-methane. This provides the basis for an efficient and sustainable integration of carbonization processes such as pyrolysis and hydrothermal carbonization (HTC) into bio-refinery concepts. The results have now been published in the renowned scientific journal “Bioresource Technology”.
The production of materials and chemicals from renewable resources usually bases on biological or thermochemical processes. The latter possess the advantage of very high reaction rates. At temperatures of 250°C and above, even complex organic compounds that are recalcitrant to biologic degradation like lignin are rapidly decomposed.
However, thermochemical processes are highly unselective in their product pattern. Besides the target products a range of more or less problematic organic compounds is formed. This decreases the product yield and causes additional costs for the waste water treatment.
The researchers in Potsdam have put focus on the liquid by-products of thermochemical biomass conversion. This includes waste waters from HTC as well as pyrolysis. Both processes are highly flexible both in their feedstocks and products and are therefore expected to fulfil important roles in future bio-refinery concepts. However, until now a major problem is: These processes form waste waters that contain various environmental hazardous substances such as phenols, furans, aldehydes and ketones.
The main product of pyrolysis and HTC is biochar, a carbon and energy-rich solid material, which can be used as fuel, but also for a range of further applications from soil amendment to carbon electronics. By-products of pyrolysis are the so-called syngas, which can be used as a fuel, and a condensate composed of volatile compounds, for which no satisfying type of use exists today.
In the HTC, a process liquid is formed which contains a wide variety of organic and mineral compounds. Thus, both waste waters from HTC and pyrolysis require an effective treatment before they can be released into the environment.
In their latest article published in the scientific journal “Bioresource Technology”, the Potsdam researchers now report on the successful anaerobic biological conversion of water-soluble pyrolysis condensates in laboratory tests.
The condensates were obtained from pyrolysis of solid digestate, which is a by-product of biogas production, at temperatures between 330°C and 530°C. Large parts of the organic compounds contained in these condensates could be degraded and transformed into bio-methane. After the biological treatment, the analysed toxic components 5-HMF, phenol, furfural, catechol and guaiacol were removed below detection limit.
Only cresol remained detectable, but was still degraded by 10 to 60 %. The temperature at which the condensate was produced had strong impact: the higher the pyrolysis temperature the less organic compounds were degraded. In detail, increasing the temperature from 330 to 530°C decreased the overall degradation efficiency, expressed as the chemical oxygen demand (COD), from 57 to 37 %.
“Our results indicate the range of synergistic options to combine thermochemical processes like pyrolysis and HTC with biogas production”, project leader Jan Mumme emphasizes the added value of these integrated systems. “In addition to the production of biochar, energy can also be obtained in form of biogas”, adds junior scientist Tobias Hübner. “Recently, high research activity is seen concerning the integration of thermochemical and biological processes following bio-refinery concepts. With our research results we want to contribute to a better economic performance and a higher sustainability of these systems”, concludes Mumme.
The use of HTC waste water for biogas production was demonstrated by the APECS researchers earlier in 2013. In another joint study with Fraunhofer Institute for Chemical Technology ICT Pfinztal, quantification of individual substances in the HTC liquid by NIR showed promising results that could lead to an advanced control of biomass conversion and, thus, to higher efficiency.
The project “APECS – Anaerobic pathways to Renewable Energies and Carbon Sinks” was funded 2009 to 2014 by the German Federal Ministry of Education and Research (BMBF) under the funding scheme „Bioenergy 2021“. Project leader Dr. Jan Mumme currently works as guest researcher with the UK Biochar Research Centre at the University of Edinburgh.
Hübner, T., Mumme, J. (2015): Integration of pyrolysis and anaerobic digestion - use of aqueous liquor from digestate pyrolysis for biogas production. Bioresource Technology, DOI: 10.1016/j.biortech.2015.02.037
Wirth, B., Mumme, J. (2013): Anaerobic digestion of waste water from hydrothermal carbonization of corn silage. Applied Bioenergy 1, 1-10. Available online at: http://tinyurl.com/oqwrksp
Reza, M.T., Becker, W., Sachsenheimer, K., Mumme, J. (2014): Hydrothermal carbonization (HTC): near infrared spectroscopy and partial least-squares regression for determination of selective components in HTC solid and liquid products. Bioresource Technology 161, 91-101. Available online at: http://tinyurl.com/lhm7op2
Dr. Jan Mumme – Leader of the junior research group APECS
Helene Foltan – Communication
Phone: +49 (0) 331 5699-820, mail: firstname.lastname@example.org
Leibniz Institute for Agricultural Engineering Potsdam-Bornim (ATB)
Max-Eyth-Allee 100, 14469 Potsdam, Germany, http://www.atb-potsdam.de
Helene Foltan | idw - Informationsdienst Wissenschaft
Forest Management Yields Higher Productivity through Biodiversity
14.10.2016 | Technische Universität München
Farming with forests
23.09.2016 | University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES)
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
24.10.2016 | Earth Sciences
24.10.2016 | Life Sciences
24.10.2016 | Physics and Astronomy