Ongoing biogas projects

Last changed: 16 March 2021

Our goal is to generate knowledge that allows a controlled manangement of the microbiological biogas process. We aim to reach high effectivity, stability and biogas production in constructed reactors, as well as a high digestate quality.

In natural environments we try to reach the opposite aim, i.e. reduced methane emissions. To reach our aim we conduct both applied and fundamental reseach, often in combination.

It is the community that matters

We evaluate different substrates in batch and continuous biogas reactors and investigate questions concerning e g pre-treatment, biogas potential, co-digestion, quality of digestate etc. An important part of our work is to generate more knowledge about the different microorganisms that take part in biogas production and how to steer this community towards high or low methane production. We thus isolate and characterise new organisms and study their physiology, metabolism and genetics. We also develop and use different molecular tools in order to detect and quantify different organisms in the complex biogas process, but also in different natural environments.

Aggregation in syntrophic communities

(Link to project description) In the biogas system, thousands of different microorganisms work in a cooperative manner to convert the organic material to methane (biogas). Of particular importance is syntrophic microbial interactions, which have shown to underpin the success of some of the most productive biotechnological systems, including the conversion of protein-rich wastes to biogas. This is a project financed by European Research Commission and by Swedish Research Coouncil.

International research in collaboration with the industry

Our research is performed in collaboration with national and international Universities and with branch organisations and industry.

Our ongoing and previous projects

Microbial surveillance of biogas plants

The microbial interplay in a biogas is very complex and if the interactions between the different organisms are disturbed this can result in low gas production and instability, sometimes even a complete process failure.

Today the biogas process is surveyed by different chemical methods but still it is often difficult to foreseen a disturbance and also to understand the degree of disturbance. In this project we investigate the possibility to use microbial indicators as a complement or alternative to chemical surveillance. The aim is to find a method that can in an early stage can show an upcoming disturbance and also clearly show how the degree of disturbance.

The project run between 2012-2014, was financed though Uppsala BioX and was performed in collaboration with different biogas plants (Göteborg Energy, Uppsala Vatten AB,  Swedish Biogas International, the Biogas plant at Lövsta, SLU and Sötåsens Biogas plant).

Managing microbial communities towards more efficient biogas production

Nitrogen-rich materials, such as slaughterhouse waste and manure etc., have a high biogas potential that also results in high levels of ammonia. High ammonia levels are attractive as this increase the value of the digestate as a fertilizer.

However, ammonia also causes instability and low efficiency of the biogas process. We have during many years studied microbial systems coping with high ammonia with the aim to find operational strategies for efficient biogas production from protein rich materials. Through isolations, characterisations and studies in digester systems we today have good knowledge of these microbial systems.

However, at present we do not have enough information to enable controlled operation towards increased growth of these organisms. Through controlled cultivations of pure cultures in under different conditions, as well as digester studies, we aim at finding key parameters for managing the microbial population towards an optimized biogas production.

The project is funded by Formas and will run 2013-2014.

Syntrophic acetate oxidizing bacteria

 - new and promising candidate for efficient biohydrogen production from waste

Syntrophic acetate oxidizing bacteria (SAOB) is a newly described organism group with promising potential for efficient hydrogen production.

When SAOB grows in pure culture they produce acetate as main end product from a variety of different organic compounds or from hydrogen/carbon dioxide.  In association with a hydrogen consuming partner the same bacteria can reverse its this metabolic pathway and uniquely produce hydrogen and carbon dioxide, as the only end products. The bacteria have been shown to perform this second mechanism in biogas processes, operating with a variety of different organic waste materials. We have in depth knowledge of SAOB from isolated pure cultures, from co-cultures, as well as from community structure analyses but to control and efficiently use SAOB we need to understand the mechanisms regulating acetate versus hydrogen production.

The aim of the proposed project is thus to unlock new and unique knowledge of microbial hydrogen production and its regulation. More specifically we will identify differences in protein and gene expression during growth as acetate producer compared to growth as hydrogen producers and investigate hydrogen production rates in microbial electrolysis cells.

The project is funded by the Energy Agency and run between 2013-2016. The project is run in collaboration between the Department of Microbiology and Animal Genetics as SLU and the Civil and Environmental Engineering at Chalmers.

StandUp for Energy

StandUp for Energy is a collaboration initiative between Uppsala University, The Royal Institute of Technology, The Swedish University of Agricultural Sciences and Luleå University of Technology.

It arose as a result of the Government’s commitment to high quality research in areas of strategic importance to society and the business sector. The overriding aims of the StandUp partnership are to reduce the costs of large-scale production of renewable and environmentally sustainable electricity delivered to the consumer, as well as to develop more cost-effective and energy efficient hybrid and electrical vehicles. Within this program we are performing research concerning biogas production from biomass, at present Salix is in focus. We investigate possibilities for increased biogas production at agricultural sites, where biogas often are converted to electricity.

At SLU the studies are performed in collaboration between three different departments, Microbiology, Plant biology and Forest Genetics and Energy and Technology.

Biogas production from lignocellulosic materials

Plant based materials as for example straw is due to its high content of ligno-cellulose difficult to degrade and as a consequence results in low gas yields. Still these materials are of interest as they are present in large amounts, in Sweden and in the world.

We are in several different project investigating different strategies to improve the biogas production from plant-based material, with straw as a model material. We are evaluating different pre-treatments and reactor configurations and also perform work in order to generate further information about the importance of the microbiology for an efficient degradation. We are studying the cellulose degrading population in different biogas reactors and look for correlations between the microbial community and the degradation efficiency and the gas production. We are also isolating new cellulose degrading bacteria and study their physiology and genetics with the goal to get tools for optimized degradation of lingo-cellulose materials in biogas reactors.

The research is financed by the Swedish Energy Agency, MicroDrivE and CSC (China Scholarship Council). Part of the work is performed in collaboration with AEPi  (Agro-Environmetal  Protection Institute) Tianjin, China.  

Farmed based biogas production

Crops and agricultural residues such as plant residues and manure, represents an important resource for future bioenergy production, including biogas production.

Thus the interest for farmed based biogas production is high in many countries in Europe and worldwide the number of farm-based plants is increasing. However, many challenges still need to be solved in order to make this technology economical feasible and widely accessible to farmers, particularly for medium and small sized farms.

1. SE-Biomethane (Small but efficient – Cost and Energy Efficient Biomethane Production)

The overall objective of this project is thus to address some bottlenecks for a positive development and to find new and innovative solutions for efficient small-scale biogas production, particularly from cellulose rich materials, e g straw and solid manure. More specifically we aim at developing;

  1. energy and cost efficient pre-treatment methods,
  2. co-digestion strategies and digester concepts for increased efficiency of biogas production from straw and solid manure,
  3. simple and low cost upgrading systems for small scale biogas plants by the use of a ash filter and
  4. methods for efficient use of anaerobic digestion residues, e g dewatering.

In total 8 different partners (UMV, DBFZ, SLU, Ultuna Egendom, Triventus, Energy Ltd and Intitytut Energii are involved in this project from three different countries, Sweden, Poland and Germany. The project runs between 2013-2015 and is financed though the EU ERA-net bioenergy research program. The department of Microbiology at SLU, is acting as coordinator.

2. Co-digestion effects in biogas production – manure and energy crops

The aim of this project is to investigate the possibility to improve the efficiency of a manure based biogas process by addition of energy crops, which compared to manure as the sole substrate could allow a comparably higher organic. Specific questions that will be addressed include

  • What are the physical and chemical parameters of the substrate that will contribute to a co-digestion effect, i.e. an improved biogas production compared to the substrates alone, when manure and energy crops are degraded together in an anaerobic digestion process.
  • How should a manure based biogas process be operated in order to reach higher efficiency after introduction of energy crops as a substrate?

The Rural Economy and Agricultural Society in Sjuhärad  (http://hs-ps.hush.se ) is responsible for the project, that is run by a PhD student in collaboration with the department of microbiology and the department of animal environment and health  at SLU. The project will initially be performed in the laboratory but results from these studies will later be implemented on a farm based biogas plant. The project is financed by the The Rural Economy and Agricultural Society in Sjuhärad and by the Energy Agency. Project period 2013-2015.  

3. Efficiency and stability in farmed based biogas production plants – importance of the microbial community structure

The project ”Evaluation of farmed based biogas production plant” is  since 2009 run by The Rural Economy and Agricultural Society in collaboration with JTI and ten companies in the biogas branch. The project is funded by that is financed The Swedish Board of Agriculture.

The overall goal of this project is to evaluate the performance of different farmed based biogas plants and to support farmers operating these plants. An additional aim is to collect information of value farmers planning to start their own biogas plant in the future. In the project the operational management is documented and the composition of substrate, digestate and gas are analysed in order to evaluate the performance of the process. In total 22 biogas plants have been analysed and the results so far illustrate large variations in efficiency and stability between the different biogas plants, even at biogas plants using similar operational parameters and substrates.

In this project the same biogas plants will be used for a microbiological survey. The community structure of both bacteria and Achaea will be analysed with molecular tools (454 sequencing) and the obtained data will be correlated with data from the chemical analysis as well as with operational data. The aim of the project is to increase the understanding concerning the importance of the microbial community structure for the function of the biogas process.

The microbial analysis will be performed in 2014-2015 and is financed by The Swedish farmers foundation for agricultural research. The project is managed the department of microbiology at SLU (main responsible) in collaboration with JTI and The Rural Economy and Agricultural Society.

Biogas production from stillage

Stillage is a side product from ethanol production possible to use for biogas production. Stillage has a high content of proteins, resulting in high yields of biogas and a residue with high nitrogen content, giving it a high value as a plant fertilizer.

Unfortunately, the high levels of nitrogen can also cause problems due to inhibition of the microbiological degradation process, giving rise to biogas. Moreover, stillage as a substrate for biogas typically results in rather high levels of hydrogen sulphide in the gas, that decrease the quality of the biogas and that also bind trace metals, essential for microbial activity. A big portion of the hydrogen sulphide is produced through the action of sulphate reducing bacteria (SRB), using sulphate originating from sulphuric acid used during the ethanol production process. SRB compete with methanogens for their substrate resulting in less methane production. 

In this project we were looking into different operational strategies for increased biogas production from stillage, i.e. to decrease the activity of SRB and to improve the possibility for growth of microbial systems producing methane at high levels of nitrogen.

The project was performed by a industrial PhD student from Tekniska Verken AB and was financed in equal parts by them and by Formas. The project ran between 2011 and 2015. 

Quality of anaerobic digestates

 – importance of substrate and operational parameters

When organic materials are degraded in a biogas process, a degradation residue (digestate) is produced in addition to biogas. This residue, also often called bio-manure, contain different plant nutrients and can thus be used as a fertilizing agent during farming.

Today we have quite good knowledge about the residue as a fertilizing agent but still some question remains to be answered for an optimal usage.  We investigated importance of substrate and operational management for the quality of the residue. The composition of the digestion residue will vary depending on the ingoing material to the biogas plant but also depending on the operational management. For our studies we used residues from different commercial biogas plants but also from more controlled biogas reactors operated in the laboratory. We investigated for example the impact on the substrate C/N quota and the operational temperature on the residue and make comparative analyses with other types of bio-manure, such as cow and swine manure. The studies were focusing on effects of the fertilization on the soil microbial community, of importance for the nitrogen and carbon turnover.

The project was financed by the department of microbiology and Formas and ran between 2010 and 2015.

Farmed based biogas production - anaerobic digestion and biogas reactor technology

Crops and agricultural residues such as plant residues and manure, represents an important resource for future bioenergy production, including biogas production.

Thus the interest for farmed based biogas production is high in many countries in Europe and worldwide the number of farm-based plants is increasing. However, many challenges still need to be solved in order to make this technology economical feasible and widely accessible to farmers, particularly for medium and small sized farms.

1. Anaerobic digestion of solid manure at a farm scale biogas plant

The objective was to study the technical, biological and economic conditions for a considerable addition of solid manure (straw-rich cattle/pig manure or nitrogen-rich poultry manure) for co-digestion with liquid manure in a wet digestion process with limited addition of water.

Solid manure contributes to approximately half of the total manure biogas potential in Sweden. Today there is a lack of knowledge on how to efficiently mix solid manure in conventional wet digestion processes. The aim was to demonstrate cost efficient co-digestion of solid manure with liquid manure in a wet digestion process where solids contribute with 60-80% of the total biogas production. The results was disseminated to local farmers with interest for biogas in demonstration activities. The study was accomplished both in a farm scale plant at Sötåsen and in laboratory scale at JTI and SLU. JTI is acted as the project leader and the project was funded by The Swedish Farmers' Foundation for Agricultural Research, Swedish Board of Agriculture, The County Administrative Board of Västra Götaland. Project period: 2012-2014.

2. BIONA - Biogas Reactor Technology for Norwegian Agriculture

The primary objective of this project was to develop cost effective biogas reactor technologies for use in Norwegian agriculture. The AD plant economy can be enhanced by increased biogas production obtained by co-digestion of manure and plant materials with energy rich substrates like fish ensilage, food waste or slaughterhouse waste. However, the AD process is sensitive to high concentrations of the ammonia produced by degradation of these protein-rich substrates. 
Microorganisms that tolerate high concentrations of ammonia can be established but these are slow-growing and can easily be washed out of the biogas reactor. The development of ammonia tolerant biofilms was proposed as a solution to this problem.

In the project the potential role of ammonia tolerant cultures was analyzed and process design criteria for these systems was suggested. The project was divided into three work packages:

  1. Ammonia tolerant biogas processes
  2. Sensor technology and process optimization
  3. High rate biogas reactors of UASB type.

The project was a cooperation between Bioforsk, Norwegian University of Life Sciences (UMB), Telemark University College (TUC), Norweigan University of Sciences and Technology (NTNU), Swedish University of Agricultural Sciences (SLU), Institute of Agricultural and Environmetal Engineering (JTI), Aalborg University, Bondelaget, Lindum, Bioplan Hardanger and FolloRen. The projects ran between 2011-2014 and was financed by the Norweigan research council.


Contact

anna.schnurer@slu.se, 018-673288

Page editor: henrik.hansson@slu.se