Note: Descriptions are shown in the official language in which they were submitted.
~ 2l~3177
A Process and an Apparatus for the Aeroblc Decompositlon
of Organlc Components
The present lnventlon relates to a process for the aeroblc
decomposltlon of organlc components ln two phases,
fermentatlon that lasts from two to twenty days taklng place
ln the flrst phase ln one or a plurallty of closed contalners
to whlch alr ls lntroduced or removed under regulatlon or
under control, dependlng on the temperature that occurs durlng
the fermentatlon; ln the second phase, after the concluslon of
the fermentatlon, the organlc components so obtalned are
removed from the contalners and sub~ected to after-rettlng.
The present lnventlon also relates to an apparatus for
carrylng out the process referred to above, wlth at least one
rettlng tank that ls connected to a ventllatlng system and
wlth a system for measurlng the rettlng temperature or the
rettlng humldlty, and an after-rettlng apparatus.
So-called blo-wastecompostlng serves to reduce the quantltles
of waste that have to be dumped or lnclnerated, and entalls
the advantage that a ma~or part of the waste that ls generated
can be reused.
DE 36 31 170 descrlbes a process and an apparatus for
fermentlng refuse has a large content of organlc components ln
a closed contalner to whlch alr can be lntroduced or from
whlch alr can be removed, the alr that ls removed belng
blologically cleansed. In practlce, thls process has been
found useful when uslng several moblle rettlng contalners, ln
whlch, ln each lnstance, mlcro-organlsms decompose the
long-chaln organlc compounds, such as cellulose, grease, and
albumen, at an average temperature between 40C and 60C. In
the subsequent thermophlllc stage of rettlng, the temperature
rlses to more than 60C whlch renders the blo-materlal
hyglenlcally benlgn.
28024-11
~IS3i77
After the conclusion of the intensive retting, i.e., after 2
to 20 days, the material matures to after-retting silage.
It is the task of the present invention to minimize the total
retting time.
This problem has been solved by means of a process as defined
in Claim 1 which, according to the present invention, is
characterized in that the after-ret is essentially constantly
ventilated during the after-retting time and turned at least
once during this time.
Whereas, according to the prior art, the second phase proceeds
more or less uncontrolled and, at all events, the silage is
mixed with other silage depending on the amount of shrinkage
that takes place during decomposition, now, the after-ret is
deliberately ventilated constantly and turned over once or
several times. This optimizes the aerobic decomposition even
in the after-retting phase, and this results in considerably
reduced compoæting time.
It is preferred that the introduction and removal of air
during the first phase, which is to say, into and out of the
closed container, and/or the ventilation of the after-ret be
carried out, at least in part, in a closed circuit, and that
the exhaust air be biologically cleansed.
The separation of the first and of the second phase from the
environment entails the considerable advantage that the odours
that are generated during the decomposition process are
avoided and, in the same way, the bacteria or fungi that are
needed for the initiation and maintenance of the decomposition
process are not allowed to escape.
In a further development of the present invention, up to 80
per cent of the after-ret exhaust air is returned so as to
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ventilate the after-ret; this brings about a considerable
reduction in the quantity of gases that have to be filtered.
In order to accelerate decomposition, it is preferred that
exhaust air from the first phase be added in order to
ventilate the after-ret; as an example, up to 20 per cent
exhaust air can be added to the quantity of gas that is
introduced into the after ret.
Whereas the biologically decomposition process of the first
phase (in one or a plurality of closed containers) takes place
as far as possible in a stationary manner, which is to say
without movement and without the retting material being turned
over, according to a further development of the present
invention the after-retting process is ventilated during
movement. It is preferred that the after-ret be moved onto a
conveyor that has openings to permit the introduction of air
and for draining liquid off, and then moved to the removal
point during the after-retting process.
This conveyor is located in a room or a container that is
closed off from the environment. The container is filled at
one end. During the after-retting process, the ret material
passes through the after-retting container or the
after-retting room to the end at which it is removed, where
the compost can be taken away. The conveyor can be operated
continuously or intermittently, so that the total retting time
is eight weeks, after-retting lasting for six to seven weeks.
It is preferred that a (fixed) turning system operate across
the whole width of the conveyor or can be moved transversely
to the conveyor system in such a manner that all of the
after-ret material that is spread across the conveyor can be
turned over.
21S3177
It is preferred that the after-ret process take place in a
system that is closed off to the outside -- apart from the
regulated or controlled introduction and removal of air. As a
result of these measures, the most favourable conditions for
the after-retting process can be set up, regardless of outside
temperature, very variable humidity, and/or wind. Unlike the
process that is known from the prior art, in which the organic
material is constantly turned over and/or ventilated from the
start, the two-phase retting process has been selected for the
present invention, and this, as described above, is divided
into an intensive ret, and a dynamic phase, i.e.,
after-retting, when the silage is turned over and moved.
According to a further development of the present invention,
the after-ret is ventilated in circulating air and the
quantity of air that is passed through is regulated on the
basis of the after-ret temperature and the oxygen content in
the after-ret exhaust air. As a result of this, it is possible
to arrive at an optimal match of the amount of air that has to
be passed through in the after-ret to the current degree of
retting. The after-ret ventilation can be pressure and or
suction ventilation, and is preferably conducted through the
bottom of an after-retting tunnel-type container.
With respect to the apparatus technology, movement through the
apparatus is effected according to Claim 10, which, according
to the present invention, is characterized in that the
after-retting apparatus incorporates a ventilating system and
at least one turning system.
Developments of the apparatus are described in Claims 11 to
20.
The after-retting apparatus is provided with at least one
exhaust-air line that incorporates a biological filter, said
biological filter serving to clean the exhaust air so that no
unpleasant odours escape to the outside environment.
21S3177
As has already been described, up to 80 per cent of the
exhaust air can be returned to the after-retting apparatus and
re-used for ventilating the after-ret, this being ensured by
appropriate routing of the line. It is preferred that the
exhaust air line from the retting container(s) be connected to
the air-supply lines of the after-retting apparatus.
According to another embodiment of the present invention, a
regulating or control system is incorporated to mix the feed
air in the after-retting apparatus from exhaust air from the
retting contA;ner, from exhaust air that has been returned to
the after-retting apparatus, and/or from local air. In the
case of a control system, the mixing of the the air is
effected according to the after-ret temperature and/or the
oxygen content in the exhaust air from the after-retting
apparatus, to which end the sensors are connected to a master
computer as a control system.
The (intensive) retting apparatus and the after-retting
apparatus form a system that is essentially closed off to the
outside -- up to the biologically filtered exposed air, so
that undesirable environmental effects, in particular
unpleasant odours, are avoided.
The after-retting system incorporates a linear conveyor
configured as a sieve base, through which the after-ret can be
ventilated and/or the water removed from it. At least one
turning apparatus, that is either mobile or arranged
transversely to the direction of movement of the after-ret, is
used to move and turn the after-ret over. In particular, the
after-retting apparatus can be in the form of a tunnel reactor
that incorporates a base of ferro-concrete parts. Pipes for
pressure and/or section ventilation and for the removal of
water are incorporated into this base.
21S3177
Depending on the quantities of material that are to be
composted, according to another embodiment of the present
invention it can be advantageous to arrange a plurality of
after-retting apparatuses adjacent to each other. In order to
avoid idle periods for the turning apparatus, it is preferred
that a single turning apparatus be provided for a plurality of
after-retting apparatuses, when the turning apparatus can be
moved from one after-retting apparatus to another with the
help of a lateral-movement system. According to another
embodiment of the present invention, if a plurality of
after-retting systems are used, a common, single input and/or
removal system can be incorporated.
One emho~ment of the present invention is shown in the
drawings appended hereto. These drawings show the following:
Figure 1: a block diagram showing the process;
igure 2a, b: two diagrammatic views of an apparatus for
carrying out this process.
As is shown in Figure 1, the material 10 that can be
decomposed organically is reduced in a first stage 11, where
it is mixed and homogenized. Any material that could damage
the system, in particular metal parts 12, are removed. The
homogenized mass is moved into the intensive retting
apparatuses 13, in which the movement of the feed air and
exhaust air is controlled by means of a process computer that
measures the particular retting temperature and retting
humidity in the closed container. Exhaust air passes through
the biological filter 14 to the atmosphere. After a period of
seven to fourteen days, the retting material is moved to one
or a plurality of containers and fed to an after-retting
apparatus 15, in that the retting material is placed on a
conveyor belt 16 (see Figures 2a, b), for example a panel-type
conveyor with sieving slots; this moves the retting material
linearly to the removal end, when turning apparatuses 18 that
21~3177
can move transversely to the direction 17 of the conveyor belt
loosen the after-ret material and mix it again. The
after-retting material is constantly ventilated through the
sieve base 16 during this linear movement. The flow of air
that leaves the after-ret material is returned, i.e., it is
once again blown through the base 16 into the after-ret
material. The remaining exhaust air 21 is passed to the
outside environment by way of a biological filter 22. The
linear conveyor 60 is located in a closed container or covered
over by a U-shaped hood-type roof 23, the arms of which extend
as far down as the ground, or to a point that is beneath the
plane of movement. Because of this, it is possible to avoid
unpleasant odours, such as those that occur during
afte-retting that is conducted according to the prior art. It
is possible to speed up the after-retting process if up to 20
per cent of the exhaust gases 19 is blown in from the first,
stationary phase 13 through the base 16.
