Page 66 - European Energy Innovation - summer 2019 publication
P. 66
66 Summer 2019 European Energy Innovation
BIOGAS
Biogas production of organic
by-products from the food
industry
By Emma Lindkvist (pictured), PhD student at Linköping University and the Biogas Research
Center, Linköping, Sweden.
disintegration, e.g. making the pieces and fats are recovered as petroleum
Atransition in the energy of substrate smaller, to enable a replacements. However, organic by-
sector towards renewable faster digestion. The substrate is products are still left for treatment
energy s ources is thereafter digested in an anaerobic as waste. The organic by-products
necessary. Anaerobic
digestion of biomass (substrate) to environment in the digesters by could be used as substrate for biogas
produce biogas is one alternative. methane-producing microorganisms. production. Given the potential for
Biogas consists mainly of methane Biogas is collected from the digesters biogas to contribute to both nutrient
(40-80%), but also carbon dioxide and the remaining organic matter, recovery and the mix of renewable
and traces of other gases. Biogas which is rich in phosphorus and energy in the energy sector, it is
can be used for heat and electricity nitrogen, can be used as fertilizer on important to understand how
generation as well as vehicle farm lands. industrial organic by-products are
fuel, if the biogas is upgraded to treated today and which conversion
biomethane. When upgraded to The food and drink industry are options are most beneficial from a
biomethane the methane content the largest manufacturing industry resource efficient perspective.
in the gas increases to around 97%. in Europe, in terms of turnover,
Biomethane can also be injected into employment and value-added. Every Resource efficiency is a term used
natural gas grids. year, large quantities of primary food more and more frequently. To be able
products from the agricultural sector to assess which conversion option
The substrate is often pretreated are refined into high-quality products of organic by-products resulting
at the biogas plant before digested (about 70% in Sweden). The industry from the food and drink industry
in the digesters. Pretreating can, produces organic waste that needs that are most resource efficient,
for example, include hygienization treatment. For example, high protein three different perspectives may be
to sanitize the substrate and by-products are used for animal feed concerned; economy, energy and
environment.
In a recent research study,
five different areas in Sweden
with multiple food and drink
manufacturers were studied. All areas
had different prerequisites. The aim
was to assess if biogas production
is a resource efficient alternative for
treating organic by-products from the
food and drink industry, compared to
other treatment methods.
For all the five areas the business as
usual were compared to two biogas
scenarios. In the business as usual
scenario (referred to as Scenario
BAU), the organic by-products
are either used as animal feed,
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