Spring 2021 EN

Biogas Journal | Spring_2021 English Issue
agitate containers with volumes starting at 500 cubic metres. The
acid is dosed through a nozzle located directly above the agitator
paddles. The amount is set based on results provided by a pH
measuring instrument. Foam is produced when the slurry is agitated
vigorously as the sulphuric acid is added. For this reason, the
agitator operator must constantly watch the contents of the slurry
container in order to prevent it from overflowing. When the desired
pH value is reached, the acidification process is stopped. When the
tank lorry has left the farm, there is no longer any risk of danger.
Currently, 26 percent of the farm fertiliser is fermented in Danish
biogas plants, of which there are more than 90. The increase is
notable because in 2012 it was just four to five percent. However,
imported biomass such as molasses or olive stones also play a role
in biogas production. “Danish farmers also consider maize to be an
energy crop after animals have eaten it,” says Jin Mi Triolo at the
University of Southern Denmark (USD) in Odense.
Professor Triolo, who researches alternative biomass for biogas
plants, thinks that more slaughterhouse waste will end up in the
digesters of Danish biogas plants in the future. She thinks a share
of 25 percent of the substrate input is conceivable. Hog operations
represent an important sector of Danish agriculture, which
is export oriented.
Biogas has a future
In the highly advanced laboratories at SDU, scientists work on
the future for biogas. This energy source could play an important
role in the hydrogen economy. Algae can also be produced in the
digester of a biogas plant. But in Odense they are also researching
material applications, such as harvesting high-quality oils from
cherry stones.
In the context of the EU Interreg project BIOCAS (BIOmass CAScade),
they share their work with German colleagues. The project
brings together 18 partners from four EU countries to cooperate in
the area of the sustainable transformation of biomass streams by
using new technologies, process sequences and business models.
Furthermore, they are working together with other local partners.
The German partners include the Heidekreis district, the 3N Competence
Centre and the University of Oldenburg.
In the meantime, Denmark is developing into a significant market
for German manufacturers in the biogas area. For the planned
construction of a mega biogas plant in Hojslev, near Viborg in the
central Jutland region, Stallkamp is producing and erecting all
of the digesters and equipping the plant with pump and agitator
technology. Lundsby Biogas ApS, located in Denmark, is the ordering
client for the large-scale project, but assembly will be executed
by the Danish sales representative Biogas Teknik A/S. The biogas
plant is designed for a total of 14 containers. The three tall digesters
will be assembled with stainless steel roofs and the remaining
11 will be equipped with gas-tight, double membrane roofs.
Author
Thomas Gaul
Freelance Journalist
Im Wehrfeld 19a · 30989 Gehrden
00 49 1 72/512 71 71
gaul-gehrden@t-online.de
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