Efficient processes for biogas production from of organic waste and renewable raw materials


© Biotech Surindo / Fraunhofer IGB

Use of organic residues from the food industry

In the production of food or in biotechnological processes, residual materials of the most varied composition are produced. Fraunhofer IGB develops individual and adapted solutions for the material and energetic use of organic residues that are generated as by-products. Organic residues that cannot be recycled are particularly suitable for anaerobic conversion into the end product biogas (methane and carbon dioxide).

© Universität Hohenheim

Productivity increase of biogas plants

Biogas plants, in which above all renewable raw materials are digested into biogas, are an important decentralized component in the expansion of renewable energies. However, there is still a need for research to make biogas production as a whole as effective as possible and thus improve the biogas yield.

Our solution: Efficient digestion processes for maximum biogas yield

The range of our services extends from digestion tests on laboratory scale to determine the degradability and the biogas yield, to investigations on pilot plant scale to determine design parameters for biogas plants, to the realization of plants on technical scale in cooperation with engineering offices. All developments are carried out with the aim of providing optimal and specific solutions for the user.

  • Feasibility studies: Investigation of the fermentability, quantification of the biogas yield of substrates / cosubstrates
  • Characterization of solids and substrates: Qualitative and quantitative biogas analysis, analysis of substrate ingredients
  • Specific analysis of processes with the aim of process improvements: elimination of faults, increase of efficiency, process optimization
  • Anaerobic processes as an alternative to aerobic processes
  • Determination of potential for increasing the performance of processes, e.g. wastewater treatment, biogas plants, sewage sludge digestion
  • Process development for anaerobic treatment of organic residues, e.g. from agriculture, food processing, production
  • Technical implementation up to pilot scale
  • Scientific support during the commissioning of processes on a technical scale
Biogas experiments at Fraunhofer IGB.
© Fraunhofer IGB
Biogas experiments at Fraunhofer IGB.

Infrastructure and equipment

  • Bioreactors of different types and sizes (laboratory, pilot and technical scale)
  • Pilot plant for environmental and bioprocess engineering
  • Mobile pilot plants in m3 scale for the generation of design data on site for the planning and construction of innovative demonstration plants

Concepts for utilization of biogas: Energy carrier, fuel, raw material

Biogas can be used in many ways. In the combined heat and power plant it supplies electricity and heat. If biogas is upgraded to biomethane, it can be fed into the natural gas grid or used as fuel for appropriately equipped vehicles. Finally, the components methane and carbon dioxide can also be used as materials. Fraunhofer IGB supports you in the realization of new utilization concepts.


Biogas couples energy, chemical and mobility sectors

Among the renewable energies, the production of biogas as "bioenergy" for the energy turnaround takes a special position: While electricity generation from the sun and wind is heavily dependent on the weather, biogas, a mixture of methane and carbon dioxide, can in principle be used to produce energy continuously.  

In addition, biogas can be stored for a certain period of time and converted into electricity and heat in a combined heat and power plant as required. If biogas is purified accordingly, the high-purity methane can also be used as a fuel (natural gas vehicles) or chemical base material – or fed into the natural gas network. In this way it links the energy and chemical sectors.


Material use of biogas: Production of basic chemicals from methane and carbon dioxide

Biogas, a mixture of methane and CO2, can be used as a substrate to produce basic chemicals or biopolymers such as polyhydroxy fatty acids. Methanotrophic, i.e. aerobic, microorganisms are used in the utilization of biogas.

Use of biomethane as fuel

© Fraunhofer IGB / Frank Kleinbach

Due to its high net energy yield, biogas is the most important bioenergy source. Biogas, a mixture of energetically usable methane and carbon dioxide, is produced during the anaerobic fermentation of organic matter. In combination with combined heat and power generation, biogas production is considered a technology with a very high CO2 avoidance potential.

In the EtaMax project, Fraunhofer IGB has shown that biomethane can also be used in the mobility sector – as a fuel for suitably upgraded vehicles. In this project, easily fermentable wet biomass with a low lignocellulose content – in particular low-cost biowaste and residual algae biomass that does not compete with food production – was completely converted into biogas using a combined, modular process with maximum energy production, while at the same time closing all material cycles. The aim is to use the biomethane purified as a vehicle fuel to power CNG (compressed natural gas) vehicles.

Biogas has also been successfully upgraded to biomethane in Brazil and is now used as fuel for the company's own fleet of vehicles. In a project funded by the International Climate Initiative of the German Federal Ministry for the Environment, a plant was built here to process the digester gas (biogas) from the wastewater treatment plant in Franca, Brazil, to natural gas quality.