From fork to farm
We convert food waste into gas, electrical power, hotwater, and compost
We recycle organic waste
Potato peels and food residues are full of energy and nutrients. Since
organic waste contains between 70 and 80 per cent of water, its
calorific value for incineration is poor. Therefore, at our facility we
convert the waste into eco-friendly biogas and nutrient-rich compost.
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1. Separation at home
Just about all types of food waste can
be separated for recycling. This goes
for vegetables, fruit, and leftovers
of meat and cold cuts. Milk cartons,
nappies and disposable tableware
and other non organic kitchen waste
cannot be converted into compost
and should be put in the domestic
waste bin. It is important that waste
is separated correctly at the source.
Organic waste is picked up by a
multiple-compartment waste
collection truck or on separate
collection routes to prevent mixing
with other types of waste.
2. Pretreatment at the facility
At Bio Vækst waste is tipped from
the collection vehicle in the reception hall. It is then mixed in a large
mixer, ripping up the waste bags. If
the waste is not separated correctly
it may be necessary to screen it in a
trommel to separate all large items.
To give waste the right structure hard
plant materials such as branches or
wood chips are then added.
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3. Treatment in closed module
The mixed waste is taken to a
treatment module where it is
unloaded with a conveyor belt placed
at the back of the mixer – piling it
all the way up to the ceiling. When
the module is full, the air and water
tight door is closed and the waste is
watered with liquid from the biogas
tank. This kicks off the biological
decomposition process. To accelerate
the process the liquid is circulated in
pipes between the biogas tank and
the waste in the treatment module.
4. Generation of biogas
The liquid and the juices from the
waste, which are full of nutrients,
are pumped to the biogas tank. Here,
bacteria convert these waste juices
into biogas using a natural process.
The biogas is fed either to a gas
engine, thus generating electrical
power and heat, or it is cleaned and
pumped to the natural gas grid.
5. Composting
When no more nutrients for biogas can
be extracted from the waste it remains
in the closed module. The recirculation
of the liquid is halted and the composting process is started by sucking
air through the waste. The air from the
process is filtered in a biofilter before
it is expelled from the module, thus
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6. Fertilisation of agricultural land
The finished compost is screened
to remove any remaining inorganic
residues. Now the compost is ready
to be spread as a fertiliser on
agricultural land.
avoiding odour nuisances. During the
composting process the temperature
in the waste mass goes up to 70
degrees Celsius, killing any unwanted
bacteria and sanitizing the material for
safe agricultural use. When the process
is over the module is emptied and the
compost is placed in large windrows
for maturing.
From food waste to gas, power, heating, and compost
Each Dane generates more than 100 kg of food waste
per year. In our facility this can be turned into:
Compost
100 kg of food waste can be converted into 40 kg of
compost. The compost contains 400 g of nitrogen,
200 g of phosphorous, 200 g of potassium, and 25 kg of
organic matter.
Power
100 kg of food waste can be converted into just about
25 kWh of power. This corresponds to the consumption
of a new refrigerator for one month.
Heating
100 kg of food waste can be converted into 100 MJ
of heating, which can raise the temperature of
1,000 litres of water by 25 degrees Celsius.
AIKAN system
The AIKAN system combines the biogasification
and the composting of organic waste. This means
that it is possible to both recover energy from
waste, and produce compost, in one and the
same system. Without moving the material
In the AIKAN system, wastes’ can is treated
in separate modules. Therefore, the facility is
able to treat different types of waste at
simultaneously and independently from each
other. In addition, treatment can be planned
according to the desired result: highest possible
energy recovery (biogasification) or fastest
possible processing time (composting).
Since the process takes place in a closed system,
emissions to the environment are limited and
therefore so are potential odour nuisances.
Waste is not moved about during treatment. Only
the liquid (leachate) is conveyed by robust pumps.
This makes the AIKAN system very reliable.
The result is the generation of methane gas,
electrical power, hotwater, and a fine compost product that can be used as a fertiliser in
agriculture. In addition to the fertilizer benefits
the compost has a soil improving effect on both
light and heavy soils. Sandy soils become better
at retaining water in dry periods, and heavy soils
become easier to work before sowing.
Hagesholmvej 7
DK-4520 Svinninge
Phone: +45 4399 5020
E-mail: [email protected]
Bio Vækst is owned by Solum A/S.
© www.tankegang.dk 06/2016 16.0289
At Bio Vækst we treat organic waste by using
biological conversion and decomposition. We
manage food waste from municipal collection
schemes, commercial food processors, packaged
food, and other biological residues.