Risø produces biogas at animal show in Roskilde

The biogas plant has been made in Risø’s Biosystems Division and this is the first prototype of a small, handy demonstration plant. It has been built from a 1000 litre intermediate bulk container. Degassed slurry coming from a biogas plant in operation makes it start. 600 litres of slurry are poured into the tank, organic waste is also added and the big crank handle is turned around a few times to mix things well. This is how to get biogas production started quickly. Biogas consists of 60 % methane and 40 % carbon dioxide. The animal show takes place in Roskilde on 4 - 6 June 2010. More information (in Danish)

We are going to show in an easily understandable way how you go from slurry and other types of waste to useful biogas while simultaneously transforming the slurry into a much better slurry product, says Sune Thomsen from Risø.

As the slurry has been used to produce biogas it has also been processed into fertilisers that are easier to absorb for the plants than slurry. And this is not the only advantage of making biogas from slurry.

”You have to spread the slurry before you sow the crops. The degassed slurry that remains after it has been used to produce biogas, can be spread once the plants have begun to grow. This will give the plants the nutrients exactly at the time they need them. You also avoid unnecessary washing out of slurry into streams and lakes, "says Sune Thomsen.

Thus the biogas production is in every way in line with the government’s proposal for Green Growth. It aims at a better nature, environment and climate. It also aims to provide a good framework for agricultural development and growth.


Stefan Heiske (left) and Morten Jensen (right) from the Biosystems Division at Risø making their homemade biogas plant ready for the animal show in Roskilde which starts on 4 June.

At the animal show the guests are going to take part in producing biogas. Risø’s scientists have brought with them their home-built bike blender. When riding a bike the guests will be dividing e.g. food scraps and other kinds of waste into fine particles, making it useful in the biogas plant instead of throwing it in the bin.

This is how the biogas plant works: Slurry and household rubbish are poured into a large tank through a lock system. The lock is needed to effectively stop the access of air. The tank contains anaerobic bacteria, i.e. to these bacteria the oxygen of the air is pure poison. A large crank handle on the side of the tank is turned around to mix the waste well with the biogas bacteria. They immediately start to stuff themselves with the waste and in return provide biogas.