Note: Descriptions are shown in the official language in which they were submitted.
- ~l 16~92
Process for re-use of
water-containing plant material
Technical Domain
The invention relates to a process for re-use of essentially
wood-free, water-containing plant material, especially grass
clippings, preparation wastes, and the like. In addition, the
invention relates to an application and a device for implementing
the process.
Prior Art
The vegetative cover of heavily used grass athletic areas
(soccer fields, playgrounds, golf courses, etc.) consists largely
of pure grass. The high capacity to regenerate and resist wear
reguired in almost all types of sports presupposes a sturdy blade
mass and correspondingly well-developed root system of turf
grasses. Turf surfaces are therefore regularly fertilized in
order to promote growth of blades and roots, among others.
According to requirements specific to particular sports
(durability, ball behavior, etc.), grass athletic areas must be
regularly mowed during the growth period (March through October).
During a perlod of growth therefore considerable amounts of grass
clippings are formed (green mass, 20,000 to 50,000 kg/hectare;
dry substance 2000 to 5000 kg/hectare3. Since on the one hand
the grass areas must be fertilized, and on the other hand the
. 2116~92
clippings themselves have considerable nutrient content, it seems ~ ;
simplest to leave the clippings on the surface and thus solve
both the problem of disposal and also fertilization. This is
admittedly possible in less demanding grass athletic surfaces
with bioactive turf bearing layers. On highly sandy soils (for `
example, superstructures according to DIN 18035, part 4, or for
greens) with low biological activity, the clippings however must
. ~
be removed for considerations of athletic technique and
cultivation.
In addition to the obvious advantages of leaving the
clippings on the turf surface, the following disadvantages must
also be considered:
a) The undesirable activity of earthworms is promoted.
b) Enrichment of the ground surface with green mass (raw
humus) adversely affects water permeability or the
water and air balance in the turf bearing layer in the
case of mineralization which is not fast enough.
c) Matting on the base of the grasses is accelerated in
the case of overly slow mineralization of blade mass.
d~ Overly large green masses or those unevenly distributed
on the surface can damage turf grasses (rotting of the
blanketed turf surface).
e) Grass clippings comprise an ideal nutrient medium for
disease pathogens (fungal diseases, for example,
fusarium asp., Corticium fuciforme, etc.). The
clippings which lie on the surface of the vegetation
promote the spread of diseases to the healthy blades of
211~92 ~ ~
.
turf grasses. Frequently a damp microclimate which
promotes transmission of diseases from one blade to
another is formed between the clippings and the ground
surfase.
If therefore the clippings are picked up from the ground or
directly collected by the mower, it is necessary to dispose of
them in a suitable manner. Clippings contain a large amount of
water (generally, 90% and more) and easily decomposable starches
and cellulose as well as nitrogen compounds (amino acids, amides,
protein, proteids, chlorophyll, etc.). On dumps or in transport -
containers an intensive mineralization process begins a few days
after cutting. The highly water-containing material collapses
and under anaerobic conditions unpleasant odors are released from
the putrefaction processes. As a result of burst cell walls,
seepage water, heavily loaded with organic and mineral materials
which endangers the soil and water can be formed. Therefore by
law it is necessary to dispose of grass clippings within a day
(for example, a rotting dump) or the clippings must be re-used
accordingly (for example, composted). The following disposal
options are known:
Dumping of clippings in approved dumps.
Advantages:
_ Convenient, but at present no longer responsible type
of disposal for reasons of ecology and economy. -
Disadvantages:
- Transport costs to the dump:
` ` 2 ~ 9 2
- Unnecessary burden on dump space which is becoming
increasingly expensive and scarce;
- Loss of valuable organic substance and plant nutrients;
- High disposal costs (dumping charges).
Burning of the clippings in trash incinerators (KVA).
Advantages:
- Convenience, but at present no longer responsible type
of disposal for reasons of ecology and economy.
Disadvantages:
- Transport costs to the incinerator;
- Need for outside energy for burning;
- Loss of valuable organic substance and plant nutrients;
- High disposal costs (charges have increased continually
in recent years).
Composting.
Composting of grass clippings is at present the type of
treatment which is most frequently attempted and practiced.
As a result of high water content, the clippings do not `
compost purely aerobically. Shortly after the compost heap
is formed, a thermophilic putrefaction process begins in
which the easily decomposable cell walls rapidly burst
release the cell plasma, and thus undesirable amounts of
seepage water are formed. The material quickly loses
structure, collapses into itself and becomes wet. With the
exclusion of air, putrefaction quickly begins, and
~ 2~16~92
unpleasant odors are released. Composting is only
successful when the green mass is mixed directly after
mowing with larger amounts of structure material (for
example, shrub cuttings, tree bark). For an aerobic -
putrefaction process, the compost heap must be regularly ;~
turned for a prolonged period of time. Plant- compatible
finished compost, depending on the structure material used,
is available (only) after a putrefaction period from 8 to
10 months.
Advantages:
- Ecologically efficient means of treatment of a biogenic ~-
waste.
Disadvantages:
- Transport costs (transport of green mass to the
composting plant and transport of the compost from the
composting plant to the application site).
- High process costs for production of compost with low
creation of value (grass clippings consists of more
than 90% water).
- High plant, machinery and personnel costs for mixing
the clippings with structure material, partially
covered storage of the composted material, turning and
sifting of the finished compost.
- Unequal energy balance: the amount of outside energy
necessary for transporting and composting of clippings
is demonstrably greater than the creation of value for
2~ 16~2
the humus and plant nutrients contained in the ~inished
compost.
- The compost consisting of grass clippings and structure
material cannot be returned to the material cycles of
an grass athletic surface.
- For compost produced based on clippings, the
corresponding sales channels must be found, for
example, in gardening and landscaping.
Fermentation of clippings together with sewage sludge using
biogas.
A~vantagas:
- Ecologically efficient type of re-use of a bisgenic
waste.
Disadvantages:
- Transport costs (transport of green mass to the sewage
treatment plant and transport of the sewage sludge from ~ `
the sewage treatment plant to the application site).
- Clippings loaded with few pollutants are mixed under
certain circumstances with burdened sewage sludge.
- Sewage sludge cannot be returned to the material cycles
of a grass athletic surface.
- High disposal cost (ARA charges are continually
rising).
In practice, the current state of affairs in the disposal or -
re-use of grass clippings and other biogenic wastes, for example,
' ' : : . .: .. ' ; ` ` ! `
~-` 2~16~92
preparation wastes (from large kitchens and food manufacture~
engenders in summary form the ~ollowing problems: ~ .
a) Storage and transport of biogenic wastes containing
large amounts of water pose problems;
b) Conventional types of disposal or re-use (dumping,
burning, composting, gasif~cation) are either not
economical or not ecologically feasible;
c) Collection and removal of clippings entails undesirable
breaking of (biological) material cycles.
d) Problems in use of compost and/or liquid fermentation .
end products which is economical and effective for ~:
: .
cultivation.
Description of the Invention
The problem of the invention is to devise a process of the . ~
aforementioned type which avoids the aforementioned problems and ~ ~ :
which in particular can be used in the care of highly cultivated
grass surfaces.
According to the invention, this problem is solved in that
the plant material is pulverized with mechanical means and is
cellularly decomposed.
Practical tests have shown that grass clippings can be
broken down into extremely small parts, preferably in the
natuially wet state or with the addition of water, using
perforated disk, corundum disk, toothed colloid mills and hammer :~
mills. Plant cells which are rich in starch, cellulose and water
are elmost c~mpletely destroyed with the releese of their
' ,
2116~92
contents. A pulpy biomass is formed. The volume of the
cellularly or colloidally decomposed material is 4 to 5 times
less than that of the fresh green mass. This advantageous loss
of volume requires smaller stacking and transport containers.
Pulverization and cellular decomposition of plant material
(in the following also called colloidal decomposition) are
designed to destroy the cell walls and allow the cell contents to
escape. In that the material is very dramatically pulverized, it
can later be placed finely distributed on the green surface or in
the soil.
Total cellular (colloidal) decomposition of the plant tissue
is not the optimum solution in each case. Technical or economic
reasons can justify a smaller degree of pulverization (in this
connection, reference is made to the mobile units described
below). For this reason, the invention is not limited to
destruction of plant material down to colloidal size. Under
certain circumstances, pulverization with partial cellular -
decomposition into the millimeter range can be adequate.
According to one advantageous embodiment, the pulverized and
cellularly decomposed plant material is separated into its liquid
portion and its fiber portion. This can be done with a filter
unit, especially a filter belt press, a centrifuge or with other
suitable separation device. The disadvantages which are caused
by the fibrous cellulose material sticking to the blades of grass
can be avoided in this way. The fiber portion consisting
essentially of cell wall material is re-used separately.
:-, : ,,, :. ; ..: -
- - . . . .. .
~6~92
Pulverized and more or less cellularly decomposed grass
clippings can be used directly as fertilizer, finely diætributed
or sprayed on~o the mown turf surface, or can be added to the
soil. In this way the following advantages accrue:
- The biomass can be easily conveyed (with pumps),
metered (with metering pumps, valves, etc.), and spread
in the desired amount on the soil or injected into the
soil (with suitable plowshares and/or spray nozzles).
- By destroying the plant cells cell plasma with the cell
organelles contained therein is released and the cell
walls which consist of cellulose are pulverized.
Mineralization of organic material therefore proceeds
more quickly due to greater surface and impro~ed
contact with bioactive soil material.
- Plant nutrients are more quickly available in
cellularly decomposed biomass injected into the soil. ;
- Saving of commercial fertilizers and thus simultaneous
reduction in the nitrate burden.
- No visual disadvantages as applied to athletic ~ -
functions due to addition of the cellularly decomposed
biomass to the turf.
The pulverized and cellularly decomposed biomass can
furthermore be easily stored in open and force-ventilated
containers (like force-ventilated liquid manure pits in ~
agriculture) over a longer period of time without causing the ~ -
emission of unpleasant odors. Interim storage can be useful, for
example, when the cellularly or colloidally decomposed biomass
.i.: . . , ,: .. : .:. : . .:: ~ -.: .. ... ,. - ;::, :
2116~L92
- -
cannot be immediately added to the soil after mowing the grass
for reasons of weather or time, or when the colloidally
decomposed biomass of a grass surface may not be reapplied to the
same surface (golf greens, etc.).
According to one preferred embodiment, fertilizer or soil
conditioners are added on a controlled basis to the cellularly or
colloidally decomposed biomass before it is applied. The grass
clippings returned to the material cycles, for example, are not
sufficient to cover the entire nutrient demand of turf plants.
Some of the plant nutrients are needed to form root mass, can be
fixed on soil parts (clay-humus complexes) in forms which are no
longer available to plants, or are washed out. A nutrient
shortage of this type is balanced in particular in the manner
described in caring ~or grass surfaces (adding fertilizers,
etc.). Of course it is not essential that the nutrient content
of the biomass be increased in this way.
The biomass which has been colloidally decomposed and
pulverized according to the invention can be handled very easily.
It can be pumped or blown and injected directly into the soil
with a slitting device (rotary hoe, cutting plow, etc.) and
metering pumps or can be spread on the turf surface. Thus all
the disadvantages which arise when the clippings are left
(untreated) on the surface are avoided. The colloidally
decomposed biomass which is brought into direct contact with the
ground is mineralized by microorganisms at an accelerated rate
and without any notable adverse effect on plant growth. The
prerequisites for this are significantly better in tha soil than
-~-` 2~ 16~92
on the soil surface (moisture content and higher biological
activity)~
- Closing of the material cycles in that the mineralized
nutrients can be reabsorbed by the plants.
- Savings of up to 90% in fertilizers.
- The process can be carried out using small, compact
units so that transport costs, charges (for dumping,
incinerating, composting, gasifying) are completely
eliminated.
In less demanding green surfaces the colloidally decomposed
(or if necessary~ only highly pulverized) biomass can be applied
directly to the vegetative cover, for example, with a sprayer,
pressure drum (liquid manure drum) or a special drip or spreading -~
device. If application takes place, for example, shortly before
precipitation, the extremely fine organic particles of the -
biomass arè washed into the vegetative cover, in which the
disadvantages as occur when the grass clippings are le~t on the
turf surface are prevented. In contrast to the undecomposed
grass clippings which remain on the vegetative cover, the biomass
according to the invention is in direct contact with the soil
material and is there~ore much more quickly mineralized. The
aforementioned type of application (with liquid manure drum, ~;
etc.) is of course rather efficient and cost-favorable. ;
Foreign bodies, solids, rocks and so forth are removed from
the waste material, preferably before colloidal decomposition,
preferably in a water bath or quite generally by floating in a
cleaning bath. In this way the required wetting is effected at
211~
the same time. Instead of water, under certain circumstances
another suitable medium can be used. In this way, for example,
the separation or cleaning process can be influenced in a
controlled manner.
To improve the cleaning effect, water can be pumped, for
example, from just below the water's surface through a number of
nozzles (pointed upwards) into the water bath. In this way, that
part of the water is replaced which has been removed together
with the wetted waste material. The water's surface is swirled
by the pumping-in according to the invention. In a simplified
embodiment, water can be allowed from above into the water bath
instead.
Depending on with what means the plant material is
pulverized and cellularly decomposed, it can be advantageous or
even necessary to wet the material to be pulverized. According
to one especially pre~erred embodiment of the invention, the
required liquid feed is effected by returning some of the
filtrate or centrifugate obtained in filtering or centrifuging.
Thus, for example, in a mobile unit there can be a cleaning bath
with relatively small liquid or water reservoir in which the
cleaning liquid (water) lost in wetting the plant material to be
cellularly decomposed is replaced by a corresponding amount of
the liquid portion of the cellularly decomposed biomass which has
been centrifuged or pressed out. However, return can be used not
only in conjunction with a cleaning bath, but also quite
generally to wet the material to be colloidally decomposed (in
particular to facilitate mechanical decomposition).
13
21~(3~'3~
If the process according to the invention is implemented in ;~
an assembly which can be joined to a mower in order to
immediately process the grass clippings and spread them again, ~;
then under certain circums~ances separation in a water bath would
be too expensive. Depending on the application, separation of ;
foreign bodies could be entirely abandoned or it could be done by
a suitable separation process, especially air separation. ~ ;
Wetting can thus also be abandoned.
Preferably the process is used for disposal or re-use of
grass clippings and/or similar plant kitchen wastes. With the ~-~
corresponding addition of water (or liquid portion pressed out of
the biomass, etc.) the process can also be used for wilted or
dried plant material.
The process is not suitable for woody, high-lignin organic
substances (wood, tree bark) as are used, for example, to produce
porous soil conditions (peat replacement).
The preferred complete colloidal decomposition of plant
material is carried out according to the invention with a ~ ~-
conventional mill. ~n the past, they were used for producing
cosmetic or pharmaceutical pastes, pulping fruits (apples, pears,
bananas, cheese, etc.) or for preparation of soaps, pastes, fats,
etc.
Reduction of the expenditure of labor and the number of
steps (for example, by mowing the grass, cellularly decomposing
the grass clippings and respreading the biomass onto the turf in
one operation) can justify incomplete decomposition of the plant
material. In addition to these especially preferred mills, for
14
2 1 1 6 '1 !~ 2.
example, in conjunction with spindle grass mowers, sickle bar
mowers, rotary mowers, flail mowers, etc. any pulverization
devices can be used which cut, strain, grind, puree, grate,
shred, etc.
For cleaning in a water bath there is preferably a tank with
a screw conveyor located above it. The screw conveyor delivers
the material floating in the water bath to the mill. For
example, there is a fill opening with a funnel above the screw
conveyor. The waste material is emptied into the funnel with
suitable metering. In the upper half of the tank there can be a
water feed pipe with nozzles (openings) pointed upward to improve
the cleaning action.
In addition, an automatic metering device is preferably
provided. It consists, for example, of a material receiving
hopper with a conveyor belt located on its bottom. In this way,
a continuously operating system can be set up.
There is advantageously a force-ventilated container for
possible interim. The biomass colloidally decomposed by the mill
or similar item is stacked in this container for further use.
The unit can be used in stationary or mobile form. In the
latter casa the different devices are preferably combined in a
special vehicle. This vehicle can be used if necessary directly ,
together with a mower with a collecting device. However, as an
independent vehicle it can also collect mowed grass, pulverize
and cellularly decompose it and respread, separated or
unseparated, onto the same grass surface. If filtering or
similar activity is done, some of the filtrate can be returned,
2~16~'3~ -
for example, to the cleaning bath (ston~ separator etc.), as
already mentioned.
One especially preferred embodiment thus comprises a mower -~ -
for cutting the grass, a catching or collecting device which
immediately takes up the grass clippings, if necessary a foreign
body separator (especially air separator) for eliminating foreign
bodies, a pulverizing device in order to cellularly decompose the
grass clippings as much as possible, and a spreading device for
scattering or spraying the cellularly decomposed biomass. -
Additional advantageous embodiments and combinations of
features of the invention follow from the detailed description ;~
and totality of the patent claims.
Short description of the drawing
The sole figure schematically shows a unit for treating and
re-using grass clippings and similar residual water-containing
plant material.
Embodiments of the invention
Material receiving hopper 2 is filled with grass clippings 1
formed by mowing the grass. This hopper has on its bottom
metering belt 3 which continually removes the grass clippings.
It is motor driven by drive 4.
~ Metering belt 3 delivers the grass clippings to mill feed
unit 5. The latter has tank 8 with water bath 7, screw conveyor
14 located horizontally above it, and an opening with funnel 6 `
located above screw conveyor 14. The clippings fall onto screw
16
` ~16~32
conveyor 14 and past it into water bath 7 and are separated from
specifically heavy impurities 12. The latter collect on the
bottom of tank 8 and can be periodically removed through
discharge opening 9.
Screw conveyor 14 is partially immersed in water bath 7 so
that, as it i5 caused to rotate by drive 15, it can deliver grass
clippings ll floating on the water's surface to the output of
mill feed device 5 and thus to colloid mill 16. Clippings ll
delivered from wa~er bath 7 are at the same time wetted in the
manner required for colloidal decomposition.
Water is continually or intermittently supplied with pipe 10
installed horizontally in the upper part of tank 8. Water feed
is controlled using motor driven valve 13. Pipe lO has a number
of nozzles or holes pointed upward which cause swirling of the
water area near the surface. It goes without saying that the
swirling should not be so intense that the specifically heavier
parts can no longer sink to the bottom.
Colloid mill 16 is located on the same geometrical axis as
screw conveyor 14 and its drive 15. It pulverizes or grinds wet
clippings 11 until the cell structures are destroyed (colloidal
decomposition). Various known mills are suitable for this
purpose:
- Toothed colloid mills (a toothed grinding set of
stainless chromium nickel steel pulverizes the
material~
- Perforated disk mills (a, for example, four blade
cutter bar rotates at high speed just above a
2~16~2
perforated plate. The upper knife blades work against
a stationary cam ring, coarsely pulverize the clippings
and press them through the stationary perforated disk.
The ejector bar rotating under the perforated disk
sucks the colloidally deco~posed biomass out of the
cutting zone and delivers it to the mill outlet).
- Corundum disk mills (the waste material is pulverized
to a fineness of roughly 1 micron between two
ceramically sintered corundum disks into a thin liquid
to pasty biomass in a continuous procedure. A rotor
grinding element rotates with high speed against the
stationary stator grinding element. In the gap formed ~ -~
by the two corundum disks, the waste material is
colloidally decomposed with high shearing, cutting and
impact forces).
These mills are sold, for example, by FRYMA-Maschinen AG,
CH-4310 Rheinfelden, Switzerland. Drive 17 of colloid mill 16,
drive 15 of screw conveyor 14 and drive 4 of metering belt 3 are
controlled in a manner coordinated to one another by common
control circuit 27. There is likewise a pump 19 which delivers
the pulpy and pumpable cellularly decomposed biomass from colloid
mill 16 to a desired site, for example, to loading station 21 or
storage tank 22 (line 18). Water feed for water bath 7 can
likewise be controlled by control circuit 27 via motor operatPd
valve 13 according to the amount processed.
~:
r.:
1~
" ~116~92
According to one preferred embodiment, at the end of line 18
there is selector valve 20 with which the biomass can be sent
alternately to a loading station 21 or storage tank 22.
Storage tank 22 in~ludes open container 23 and motor (motor
25) driven stirring apparatus 24. If necessary, biomass can be
removed via drain cock 26.
By means of the stirring apparatus, a ventilation fan or
similar apparatus, anaerobic fermentation processes in open
container 23 are prevented (unpleasant odor development).
If it is desirable that the nutrient content of the
colloidally decomposed biomass be additionally supplemented, or
if any auxiliary agents are to be added, this can be done either
in storage tank 22 or only in the corresponding assembly before
spraying (for example, in a tanker truck or in the spreading
device).
According to one preferred embodiment, there is filter belt
press 28 (of conventional design) downstream of pump 19. This
press presses the liquid portion which is collected in filtrate
collec~or 30 out of the pumpable biomass. Filter residue 29 is ~ ~-
separated for purposes of separate re-use. Pump 31 pumps the
filtrate to storage tank 22. Selector valve 32 enables switching
from nonpressed biomass to pressed biomass.
Separation of the biomass is recommended especially in
caring for demanding sports grasses (for example, golf greens).
It. is here that it will be possible to apply the grass clippings
to the same turf surface once again.
With unfiltered biomass the following problems can arise:
19
-` 21~.6~92
If cellularly decomposed grass clippings are sprayed in
liquid form (suspension) onto ~he mowed grass surface, the
cellulose fibers (pulverized, fibrous cell wall material)
continue to stick to the blades in the manner of a felt-like
coating. Only the liquid (cell plasma plus cell contents plus
water) seep almost invisibly into the turf or into the surface of -
the ground. Cellulose fibers adhering to the blades make the
grass slippery in the wet state and decompose only poorly due to
lack of contact with the ground. Dried fibers impart a yellow
aspect to the sod and promote increased formation of grass felt. --~
Tests have shown that cellulose fibers which adversely -~
affect the grass surfaces can be most easily separated by
filtration or centrifuging from the liquid cell contents.
The biomass which is formed following mill 16 is thus
continuously divided into two groups of material. The filtrate
. .
or centrifugate (which contain the plant nutrients N, P, K, Ca,
Mg, Fe in different solubility stages which determine value) of i~
the cellularly decomposed grass clippings, in contrast to the
unseparated biomass, can be easily spread with the most simple
spraying devices, uniformly and without visible residues on the ~-
grass surface. The proteins, carbohydrates, fats, salts,
vitamins, hormones and various other compounds contained in the
cell plasma reach the soil and are made available to the plants
there by microorganisms within a few hours.
The wall substance in green plants or the residue obtained
during filtration or centrifuging consists of cellulose. The
carbon-hydrogen-oxygen compounds, in contrast to the cell plasma,
~ '
: ~ . ~ . ' ' . ': , : . ` ' . . ! ': . ,, ,, ~
~ 16~2
contain no substances valuable for plant nutrition. The filter
residues are therefore sent for composting, for example. During
the putrefaction process, the organic substance decomposes into
carbon dioxide gases (Coz) and water.
The pressed out or centrifuged cell wall material, compared
to untreated grass clippings, represents a fraction of the
initial volume and weight. The amount of material from a grass
athletic area can thus be stored or transported in an extremely
small space and causes neither undesirable seepage water nor
unpleasant odors of decay.
As already indicated several times, the process can be
carried out not only with stationary, but also with mobile
machinery and equipment. The latter make transport to a central
location (for cellular decomposition) and afterwar*s transport
back to apply the biomass to the grass surface superfluous. The
grass clippings can then be cut, pulverized, cellularly
decomposed, and applied in one operation.
For this reason, a mower of suitable type (reel mower,
sickle bar mower, rotary mower, flail mower, etc.) is equipped
with a device which catches the cut grass directly from the
cutting tools (for example, reel) without residue. Aspirators
(fans), pick-ups, conveyor belts, screws and others are suitable
for catching. These devices are known in the most varied
designs.
In principle, foreign bodies can be separated as in the
stationary version. Carrying along a water tank does make the
special vehicle large and heavy. Therefore preferably air
2 ~ 2
separators or aspirators are used as separators. In golf greens
which are cut with reel mowers, the number of foreign bodies is
negligibly small. Therefore, in an equipment combination to be
used for this purpose, separation of foreign bodies can be
abandoned completely. Then, for example, appropriately durable
pulverizing devices which are not vulnerable to foreign bodies
can be used.
If some of the filtrate is to be returned in the embodiment
shown in the figure, there should be a return line which branches
after pump 31 and empties into tank 8 (stone separator). Return
can take place by intermittent switching sr by continuous
branching of a partial flow of the filtrate. A controllable
valve can be provided to meter the returned liquid portion; the
valve is controlled depending on the liquid level in the cleaning
bath.
The pulverizing device can be supplied with grass clippings
using different conveyor elements according to take-up of
clippings beginning with the cutting tool of the mower (for
example, screw conveyor as in the stationary embodiment or a
fan).
~ o pulverize the grass clippings, in addition to the
aforementioned mills, devices are also used quite generally in
which organic substances or plant tissue and cell matexial can be
suitably pulverized, smashed, decomposed, broken open, etc. For
continuous cellular decomposition of the grass clippings in -
mowers, therefore rotating blade shafts with opposing blades,
cutting or grinding rollers rotating in opposite directions as
-~
:
' ' , ' ~ ,' ~ ''
22
2 1 ~ 6 ?~ ~2
:
well as aspirators, fans and so forth which cause the material to
be pulverized in addition to pneumatic material delivery can be
considered especially advantageous.
Pulverization of the grass clippings with or without water
(or biomass filtrate and so forth) is conceivable.
In the assemblies under discussion here, the biomass must be
respread onto the mowed grass surface in the same operation. The
pulverized grass clippings tend to form clumps, especially
without the addition of water. It is therefore of decisive
importance that the biomass can be placed on or in the soil in a
form as finely distributed as possible. If the biomass is liquid
or can be pumped, it can be spread by spraying or sprinkling
nozzles as well as drip systems. If the grass clippings are
pulverized without the addition of water, a pulpy mass with
relatively high consistency is formed which can no longer be
pumped and sprayed in liquid form. Preferably therefore rotating
disintegrators ~for example, toothed shaft) and/or fans for
material atomization are used.
The machines and devices described can be driven by
electricity from the grid or a generator as well as with internal -
combu~tion engines and hydraulic motors. The latter is
especially of interest when the devices form integrated parts of
a special vehicle for mobile use. The metering device, foreign
body separation and mill feed can be controlled automatically,
depending on mill performance.
The invention is of course not limited to the aforementioned
embodiment.
~ .,
-- 2 1 1 6 ~ 9 ~
In particular the mill feed device need not be arranged
axially in front of the mill. -~
Removal of foreign bodies can take place differently or it -
can even be entirely omitted. Metering by means of a metering
belt represents only one of several possibilities.
Instead of several individual motors, a single motor to
which the devices to ~e driven are joined via suitable ~-
transmissions can also be provided. This is advantageous, for
example, when the devices are installed permanently on a truck or
form part of a special trailer.
According to one especially preferred embodiment, the
colloidally decomposed biomass which may have nutrients added as
necessary is introduced directly into the (slit or scratched)
soil. Scratching or slitting of the soil necessary for this
purpose takes place preferably with a device as described in EP~
0 466 658.
The invention was described based on recycling of grass
clippings for athletic grass surfaces. The invention of course
is not limitad to this especially preferred application. Thus,
there are other possible applications in agricultural, vegetable ;
gardening, community, commercial and/or industrial re-use of
biogenic wastes.
At present, for many communities, disposal of kitchen wastes
poses major technical and economic problems. In handling or in
ecologically and economically feasible re-use of kitchen wastes,
essentially the same problems occur as in grass clippings.
Kitchen wastes treated with the process according to the ~ ~ -
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24
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invention can be used like the colloidally decomposed grass
clippings. In addition to the aforementioned advantages of the
invention, it should be emphasized that colloidally decomposed
kitchen wastes can also be added to the soil during the
cultivation season, for example, to rows of corn, sugar beets and
vegetable crops, without adversely affecting plant growth. -
Costly interim storage as is the case with compost is largely
eliminated.
Kitchen wastes are generally unattractive. Their components
are pulverized using the process according to the invention until
they are unrecognizable; this is a great advantage to the user.
Likewise, biogenic wastes containing large amounts of water,
similar to grass clippings, from agriculture (for example, "
harvest residues) and vegetable gardening (for example,
preparation wastes) as well as from trade and industry (for ~`
example, the food industry, catering trade) can be used with the
invention.
The green mass which grows along roads and highways is `~
heavily burdened with pollutants (for example, lead), therefore
its disposal or re-use as roughage or provender is extremely ;~
problematical. Care of green belts, slopes, etc., is at the same
time very costly and uneconomical and ecologically questionable.
The gathered material must be mowed, loaded, transported and
dumped at high mechanical and personnel cost.
The material gathered from road edges, slopes and so forth
can be returned in an economical and ecologically useful manner
to the material cycles of green areas of all types at the origin
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according to the invention by spreading colloidally treated green :-
mass directly on~o the mowed green surfaces without adversely :~
affecting plant growth.
In summary, it can be stated that by means of the invention,
a completely new, ecologically and economically advantageous
process for disposal or re-use of water-containing green wastes
has been devised.
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