BRC Newsletter nr. 7 is out!

Biogas Research Center: our latest newsletter is out!

Our idea is to provide a way for you to keep up informed on interesting upcoming and last activities carried out  in BRC.
Click on the image below to get to newsletter no. 7/2020 (in Swedish).

Here you will also find all our previous newsletters during the ongoing stage.

Have a nice reading!

Biogas solves several environmental challenges

 

Mats Eklund.

“If biogas is produced properly, there are no disadvantages. Most other sources of energy involve some form ofhazards or risks, and researchers normally refer to this as problem exchange. Nuclear energy may be advantageous from, for example, a climate-changeperspective, but it involves major risks and problems with waste.”, says Mats Eklund. Photo: Magnus Johansson.

Problems are connected

Waste management, the use of renewable fuels and achieving sustainable food production – these major challenges are facing cities and the surrounding countryside all over the world. Huge amounts of waste must be managed, the transport system and public transport must be expanded and function efficiently, and agriculture must produce food in a rational manner. And this is all to be done in an eco-friendly and climate-smart manner.

Mats Eklund, director of the Biogas Research Center, claims that biogas can solve these three problems. Seeing biogas only as a fuel, which we often do in Sweden, leads us in the wrong direction.

“Yes, that’s what we think. We very much want to stimulate a broader, systemic view. Biogas is an excellent fuel with benefits for the climate, but it is also much more”, he says.

Graphic illustration of biogas production.

The nordic model for biogas production.

These three areas are linked in the Nordic model for the production and consumption of biogas. Waste-water sludge, waste from abattoirs, and other food waste can be collected and used as raw material to produce biogas. The gas is then upgraded to vehicle fuel, which is an excellent fuel for town buses, while the biofertiliser produced as a by-product can be used as plant nutrition in agriculture. From a climate perspective, the product is preferable to both fossil mineral-based fertilisers and natural manure.

Click here to read the full article.

 

BRC new publication!

Methane potentials and organic matter characterization of wood fibres from pulp and paper mills: The influence of raw material, pulping process and bleaching technique

Eva-Maria Ekstrand, Mattias Hedenström, Bo Håkan Svensson, Sepehr Shakeri Yekta, Annika Björn

Highlights

• Kraft and sulphite fibres had high and stable CH4 potentials (390–400 Nml CH4 g VS-1).
• Shifts in raw material gave large variations in CH4 potential for CTMP fibres.
• Removal of lignin was the most important factor for high CH4 potential.
• Bleaching of CTMP softwood improved CH4 potential, likely by deacetylation.
• Unbleached TMP fibres were inhibitory to AD, while bleaching alleviated this effect.

Abstract: During the process of pulp- and papermaking, large volumes of fibre-rich primary sludge are generated. Anaerobic digestion of primary sludge offers a substantial potential for methane production as an alternative approach to the inefficient energy recoveries by commonly used incineration techniques. However, a systematic study of the importance of upstream process techniques for the methane potential of pulp fibres is lacking. Therefore, biochemical methane potentials were determined at mesophilic conditions for 20 types of fibres processed by a variety of pulping and bleaching techniques and from different raw materials. This included fibres from kraft, sulphite, semi-chemical, chemical thermo-mechanical (CTMP) and thermo-mechanical pulping plants and milled raw wood. The pulping technique was clearly important for the methane potential, with the highest potential achieved for kraft and sulphite fibres (390–400 Nml CH4 g VS− 1 ). For raw wood and CTMP, hardwood fibres gave substantially more methane than the corresponding softwood fibres (240 compared to 50 Nml CH4 g VS− 1 and 300 compared to 160 Nml CH4 g VS− 1 , respectively). Nuclear magnetic resonance characterization of the organic content demonstrated that the relative lignin content of the fibres was an important factor for methane production, and that an observed positive effect of bleaching on the methane potential of softwood CTMP fibres was likely related to a higher degree of deacetylation and improved accessibility of the hemicellulose. In conclusion, fibres from kraft and sulphite pulping are promising substrates for methane production irrespective of raw material or bleaching, as well as fibres from CTMP pulping of hardwood.

You can read the article here:

Ekstrand et. al 2020. Biomass and Bioenergy 143: 105824

 

BRC new publication!

Post-treatment of dewatered digested sewage sludge by thermophilic high-solid digestion for pasteurization with positive energy output

Erik Nordell, Jan Moestedt, Julia Österman, Sepehr Shakeri Yekta, Annika Björn, Li Sun, Anna Schnürer

Highlights

• Thermophilic dry digestion of DDS increases methane yield by 6%.
• Thermophilic dry digestion of DDS at 52 °C efficiently converts organic N.
• Thermophilic dry digestion of DDS is stable at high free ammonia levels (2 g/L)
• Increasing ammonia level enriches members of the methanogenic family WSA2.
• Sanitization of DDS by thermophilic dry digestion has a positive energy balance.

Abstract: This study investigated the possibility to use thermophilic anaerobic high solid digestion of dewatered digested sewage sludge (DDS) at a wastewater treatment plant (WWTP) as a measure to increase total methane yield, achieve pasteurization and reduce risk for methane emissions during storage of the digestate. A pilot-scale plug-flow reactor was used to mimic thermophilic post-treatment of DDS from a WWTP in Linköping, Sweden. Process operation was evaluated with respect to biogas process performance, using both chemical and microbiological parameters. Initially, the process showed disturbance, with low methane yields and high volatile fatty acid (VFA) accumulation. However, after initiation of digestate recirculation performance improved and the specific methane production reached 46 mL CH4/g VS. Plug flow conditions were assessed with lithium chloride and the hydraulic retention time (HRT) was determined to be 19–29 days, sufficient to reach successful pasteurization. Degradation rate of raw protein was high and resulted in ammonia-nitrogen levels of up to 2.0 g/L and a 30% lower protein content in the digestate as compared to DDS. Microbial analysis suggested a shift in the methane producing pathway, with dominance of syntrophic acetate oxidation and the candidate methanogen family WSA2 by the end of the experiment. Energy balance calculations based on annual DDS production of 10 000 ton/year showed that introduction of high-solid digestion as a post-treatment and pasteurization method would result in a positive energy output of 340 MWh/year. Post-digestion of DDS also decreased residual methane potential (RMP) by>96% compared with fresh DDS.

You can read the article here:

   Nordell et al. 2021. Waste Management 119 (1): 11-21

Biogas in a sustainable society: a course for you who want to know all about biogas!

The course will provide you knowledge in all aspects related to biogas. You will get an understanding of the whole cycle which includes recycling of residual products, production of fuel and biofertilizer and much more. It suits you who are interested in working with the future transition to a circular economy and climate neutrality.

Conversion pathways to achieve our climate goals must take place quickly and sustainably. Biogas is one of the solutions that has a significant role in our future and fossil-free society. This is a course for you who want to get an overall picture of biogas – how it is produced and contributes to a circular and resource-efficient society.

Next course: 18 Jan – 23 Mar 2021

Deadline for applications: 15 October 2020

Apply here!

Click on the image below for more information about the course:

BRC Newsletter nr. 6 is out!

Our latest BRC newsletter is out!
Our idea is to provide a way for you to keep up informed on interesting upcoming and last activities carried out  in BRC.
Click on the image below to get to newsletter no. 6/2020 (in Swedish).

Here you will also find all our previous newsletters during the ongoing stage.

Nice reading!

BRC new publication!

Shaping sustainable markets—A conceptual framework illustrated by the case of biogas in Sweden

Mikael Ottosson, Thomas Magnusson, Hans Andersson

Abstract: By merging findings from transition studies with recent literature on market-shaping, this paper outlines a conceptual framework that describes the shaping of sustainable markets. The framework comprises three critical processes: enabling exchange practices, proving the system and constructing the narrative. Individually, these processes generate different kinds of value – traded, demonstrated and expected value – and the value output from each process serves as input to the other two processes. Hence the value streams link the processes together. We illustrate the framework by analyzing market-shaping processes for biogas in Sweden. The case analysis shows how public and private actors have engaged in a multitude of activities that have built up the market-shaping processes. The analysis highlights the recursive nature of sustainable market-shaping, showing how key actors must repeatedly respond to tensions resulting from growth and aspirations of growth.

You can read the article here:

BRC new publication!

Cleaner heavy transports – Environmental and economic analysis of liquefied natural gas and biomethane

Marcus Gustafsson & Niclas Svensson

Abstract: Looking to reduce climate change impact and particle emissions, the heavy-duty transport sector is moving towards a growth within technology and infrastructure for use of liquefied natural gas (LNG). This opens an opportunity for the biogas market to grow as well, especially in the form of liquefied biomethane (LBM). However, there is a need to investigate the economic conditions and the possible environmental benefits of using LBM rather than LNG or diesel in heavy transports. This study presents a comparison of well-to-wheel scenarios for production, distribution and use of LBM, LNG and diesel, assessing both environmental and economic aspects in a life cycle perspective. The results show that while LNG can increase the climate change impact compared to diesel by up to 10%, LBM can greatly reduce the environmental impact compared to both LNG and diesel. With a German electricity mix, the climate change impact can be reduced by 45 – 70% compared to diesel with LBM from manure, and by 50 – 75% with LBM from food waste. If digestate is used to replace mineral fertilizer, the impact of LBM can even be less than 0. However, the results vary a lot depending on the type of feedstock, the electricity system and whether the calculations are done according to RED or ISO guidelines. Economically, it can be hard for LBM to compete with LNG, due to relatively high production costs, and some form of economic incentives are likely required.

You can read the article here (in English):

    Gustafsson & Svensson 2020. Journal of Cleaner Production 123535

BRC new publication!

Dimensions and characteristics of biogas policies – Modelling the European policy landscape

Marcus Gustafsson & Stefan Anderberg

Abstract: Biogas solutions typically span across several sectors, such as waste handling, energy and transport. While this can be an advantage in comparison to other alternatives, it also creates an intricate policy structure that is challenging to overview, making it difficult to evaluate consequences of different policy changes that might not be directly related to biogas. This article presents an attempt to describe the institutional conditions for biogas solutions in the EU by defining the dimensions and characteristics of policies and policy instruments influencing biogas. A five-dimensional model of biogas policies is proposed: type of policy; administrative area; administrative level; targeted part of the value chain; and continuity and change over time. This reflects the complexity of the conditions for biogas solutions and constitutes a platform for describing, discussing and developing biogas policies. From the proposed model, it becomes clear that biogas policy is a very dispersed and incoherent policy area. Thus, there is an apparent risk that the responsibility for biogas policy is diffuse and has no obvious owner among the involved actors, making the framework of biogas policies patchy and ineffective. This model can contribute to an improved overview of biogas policies, and can be used as a tool for comparing the policy landscapes in different countries.

You can read the article here (in English):

  Gustafsson & Anderberg 2021. Renewable and Sustainable Energy Reviews 135: 110200

Thesis Project Opportunity!

Thesis Project within Biotechnology

We offer thesis project to student with an education in technical biology, chemical biology, chemical engineering or similar, and with laboratory experience. This project is industrially relevant with a potential real impact on the use of digestate after anaerobic digestion.

Lab-scale biogas reactors

Lab-scale biogas reactors at Tema Environmental Change (Photo: Eva-Maria Ekstrand)

Improved dewaterability of digestate from anaerobic digestion by the addition of pulp and paper mill primary sludge

Anaerobic digestion (AD) of biological waste for biogas production is an important process in today’s society, both in terms of waste reduction as well as the generation of a carbon neutral fuel. Reuse of the nutrient-rich residue (digestate) is essential and can have a significant effect on the economy of the process. The digestate often contains > 90 % water, and therefore dewatering can be an important step to lower the cost for transport to potential customers. This project aims to investigate if the addition of pulp and paper mill primary sludge to the AD process can improve the dewaterability of the sludge, and thereby increase its use and value on the market.

In short, the student will carry out a laboratory study using lab-scale biogas reactors primarily digesting food waste. Primary sludge (rich in fibres) from different types of pulp mills will then be added to the reactors, and the biogas production and dewaterability of the sludge will be assessed.

Supervision

The thesis project is supervised by researchers from LiU, and the project is part of a research area in the Biogas Research Center (BRC), a national competence center financed by the Swedish Energy Agency, LiU, the Swedish Agricultural University (SLU) and several industrial partners. The student will be invited to take part in and present their results in one of the center’s larger meetings, where several companies will be present. Desired starting date is September 2020, but this can be discussed.

We are looking for a student with an education in technical biology, chemical biology, chemical engineering or similar, and with laboratory experience. This project is industrially relevant with a potential real impact on the use of digestate after anaerobic digestion.

Contact

LiU/BRC: Eva-Maria Ekstrand, eva-maria.ekstrand@liu.se

(From https://liu.se/en/article/thesis-project-in-improved-dewatering-of-residual-rot-after-biogas-production)