Note: Descriptions are shown in the official language in which they were submitted.
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COMPOSTING METHOD AND DEVICE
FIELD OF INVENTION
[0001 ] The present invention relates to a method and device that enhances
the efficiency of biological reactions, particularly the rate of production of
compost, at both the domestic and industrial level.
BACKGROUND OF THE INVENTION
[0002] There is an ever-increasing demand to reduce the amount of waste
that goes to landfill sites. The need to reduce waste is particularly pressing
in
densely populated areas. Many urban areas have introduced blue, grey
and/or green boxes for recycling to try and address this need.
[0003] Composting is gaining popularity as a means of reducing or recycling
organic waste. Composting is an appropriate way of handling various types of
waste such as yard waste and kitchen waste. Materials such as grass
clippings, leaves, twigs, fruits, vegetables, egg shells, grains and the like
are
all suitable for composting. It is estimated that between one-third and one-
half
of household waste can be composted. This would reduce the need to
relocate as much garbage and also reduce the associated costs.
[0004] Composting devices typically comprise a receptacle for containing the
waste material. Certain environmental factors are also required. These
include moisture, air, warmth and certain bacteria or worms. For optimal
results, the organic material must be kept damp and there must be sufficient
airflow within the mass since oxygen is required for the process. Without a
sufficient amount of air, an anaerobic process may take place that results in
malodorous waste.
[0005] Waste is preferably digested to provide a welllgranulated compost
material that is pleasant smelling. In order to expose as much of the material
as possible to the air, it is necessary to occasionally mix the waste
material.
[0006] United States Patent No. 6,855,527 describes a method of biotreating
and recovering valuable metals from metal bearing refractory sulfide ore
using a bioreactor. The process includes mixing the waste with coarse
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substrates, in particular rock. The rock is selected fro the group consisting
of
lava rock, gravel and barren rock containing carbonate minerals.
[0007] United States Patent No. 6,450,362 describes a compost bin that is
basically a bendable circular wall that has closures at each sidewall to form
a
cylindrical compost device. The closure means make it easy to open the
cylinder and mix the compost occasionally. When the cylinder is opened and
the bin is removed from around the compost, the compost pile can be easily
turned from all sides. No heavy lifting is required in order to move, rotate,
or
empty a compost filled bin.
[0008] United States Patent No. 6,576,462 describes another type of
composting device that is a rectangular container. There is an opening door
in the front panel. The door can be opened to extract compost or to stir the
contents. The device also has a removable top, which has a reflective
surface on one side and non-reflective surface on the other side.
[0009] United States Patent No. 6,029,918 discloses a kitchen waste
composter. Vegetable matter is composed in an outer drum that can be
rotated within an outer housing. By rotating the drum, the waste material is
mixed for enhanced bioreactions.
[0010] United States Patent No. 5,730,524 is directed to a coupling device
that interconnects the openings of two garbage cans like containers. When
the connector is put on between the two garbage cans, the interiors of the two
receptacles are in communication with each other. Waste material is
deposited into one of the containers and then the connector and the second
container are mounted on top. As the composting process proceeds, the
material inside the receptacle can be mixed by inverting the system so that
the waste moves from one receptacle to the other.
[0011] Many existing composting devices are labor intensive, mechanically
complicated and/or do not produce a high enough compost production rate.
Particularly in urban areas, there may be a shortage of space to have multiple
or large composters to increase the production rate. Thus there remained a
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need for a novel device and method to increase the rate of production of
compost in a composting apparatus.
SUMMARY OF THE INVENTION
[0012] The present invention relates to bioreactors for the treatment of waste
material. The waste is treated to increase the surface area available for
reactions to take place and to increase the rate of reaction. While
bioreactors
that include means for mechanically mixing to increase surface area are
known, the present invention works at a micro-level which leads to a much
greater surface area. The present invention addresses the need to provide
an improved bioreactor method and device.
[0013] In one aspect of the invention, an improved bioreactor for composting
of waste material is provided.
[0014] A method of enhancing the rate of production of compost is also
provided. The method comprises applying rapid vibration to waste in a
compost receptacle. The rapid vibration is preferably, but not necessarily,
achieved by ultrasonic vibration.
[0015] In one preferred embodiment the waste is suspended in a liquid
medium and the ultrasonic waves are applied to the liquid.
[0016] In another embodiment, the ultrasonic waves are applied by a number
of rods inserted into the interior of a waste receptacle.
[0017] In yet another embodiment, a stirring rod that stirs waste in a
receptacle emits ultrasonic waves.
[0018] In another aspect of the invention, a bioreactor is provided. A
preferred bioreactor according to the invention is a composting device. The
device comprises a bin for receiving waste material and a transducer for
emitting ultrasonic waves.
[0019] The device of the present invention may be permanently installed or it
may be portable.
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[0020] This summary of the invention does not necessarily describe all
features of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021 ] These and other features of the invention will become more apparent
from the following description in which reference is made to the appended
drawings wherein:
[0022] FIGURES 1A and B shows a compost device in accordance with one
embodiment of the present invention;
[0023] FIGURES 2A and B shows a compost device in accordance with
another embodiment of the invention;
[0024] FIGURES 3A and B shows yet another embodiment of a compost
device of the present invention;
[0025] FIGURES 4A-C illustrate the effect of ultrasonic vibration on the
decomposition of cabbage;
[0026] FIGURE 5 is a graphic comparison of the rate of decomposition of
carrot with and without ultrasound; and
[0027] FIGURE 6 illustrates the effect of ultrasound on decomposition of
onion.
DETAILED DESCRIPTION
[0028] While composting is clearly an advantageous way to deal with waste,
many people are reluctant to compost kitchen waste. This may be because
current compost devices are often perceived as producing a rotting mass of
foul smelling matter. The present invention addresses this problem by
providing a method and device that increases the surface area of the waste
so that more efficient biodegradation occurs. An efficient aerobic process
results in a well-granulated compost that is odorless.
[0029] In the present invention rapid vibration is are applied to waste
material
in a receptacle. A preferred means of applying rapid vibration is through the
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use of ultrasound. However, for heavy equipment at the industrial level it may
be difficult to apply sufficient ultrasonic vibration and other means of
applying
rapid vibration may be used. The present invention encompasses the use of
all types of rapid vibration for the methods and devices. Although specific
examples are provided for ultrasonic vibration, it should be understood that
other types of rapid vibration may be used.
[0030] For ultrasonic vibration, the ultrasonic waves may be applied through a
liquid medium, such as water in which the waste material is soaked. The
receptacle is subject to the ultrasonic vibration. The receptacle is
preferably
made from a corrosion resistant material such as stainless steel, tiny hard
materials such as wood chips, ceramics, glass or metal may be added to the
liquid to enhance the effect. Preferably a decomposable material, such as
wood chips, is used. This results in increasing the surface area that is
exposed for composting activities.
[0031] Referring now to the Figures, Figures 1A and 1 B illustrate a
rectangular shaped compost receptacle 10. The receptacle 10 comprises a
base 12, four walls 14 and a top 16. It is shown containing waste material 20
and a liquid medium 22. A coarse material such as wood chips 24 may be
dispersed within the waste material. In the illustrated embodiment an
ultrasonic transducer 28 is mounted on the bottom of the compost receptacle.
The transducer applies ultrasonic rays to the compost receptacle and
through the liquid medium and the waste material.
[0032] Ultrasonic waves can be applied as a pretreatment or during the
composting period. In one embodiment the ultrasonic waves are applied by a
number of pins or thin rods that can penetrate through the waste material
deposited on the soil. The pins or rods are attached to a plate that provides
the ultrasonic vibration. The pins may be permanently inserted into the
material or they may be temporarily inserted and then removed after
application of the waves.
[0033] In the embodiment shown in Figures 2A and 2B, a rectangular shaped
composter is provided. The composter 30 comprises a receptable 32 and a
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lid 34. Waste material is put inside the receptacle of the compost device. An
ultrasonic transducer 36 is associated with the lid of the composter. In this
embodiment, a series of pins or rods 38 are associated with the transducer.
When the transducer 36 with the rods 38 is inserted into the waste material
40, ultra sonic vibration is applied along the rods to the waste material. In
a
preferred embodiment, the surface of the pins or rods may be grooved or
etched to provide a scrubbing effect to the waste material.
[0034] In another embodiment the ultrasonic waves can be applied via stirring
tools that are provided in the compost device. Stirring tools are sometimes
provided in compost devices since mechanical mixing is known to be effective
in accelerating decomposition. In devices and methods according to the
present invention, various types of stirring tools or agitators are connected
to
a transducer to deliver ultrasonic waves to the waste material. It is clearly
apparent that various types of configurations can be used to apply the
ultrasonic waves to the waste material and that the invention is not limited
to
the specific examples given above.
[0035] Another embodiment of a compost system according to the present
invention is illustrated in Figures 3A and 3B. The compost system includes a
screw mechanism 52 that can be used to transport and/or mix waste. In this
embodiment, an ultrasonic transducer 54 is operatively associated with the
screw transporter or screw mixer. The surface of the screw threads may be
grooved or otherwise roughened to provide an improved scrub effect on the
waste material 56. As waste material flows through the screw mechanism, it
is treated with ultrasonic vibration.
[0036] While simple types of compost devices have been described above for
exemplary reasons, it is clearly apparent that the present invention
encompasses any type of compost device that includes an ultrasonic inducer.
It is contemplated that any type of compost system can be adapted to a
device of the invention including an ultrasonic transducer. Compost devices
may be manufactured incorporating a transducer or existing devices may be
modified by an "add-on" transducer. According to the present invention, an
ultrasonic transducer can be applied to any configuration of composter device
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including large-scale industrial devices. Both large and small-scale devices
are encompassed. This includes, for example, small kitchen units, units for
multi-unit dwellings such as apartment houses, devices for treatment of food
waste from institutions and restaurants and large-scale municipal or regional
composting devices. In addition, while the ultrasonic device has been
described primarily for use with a composting device, the method of the
invention of applying ultrasonic vibration to waste material to increase the
reactive surface can be applied to other applications. A compost device can
be generally referred to as a bioreactor. According to the present invention,
ultrasonic vibration is applied to any type of bioreactor to increase the rate
of
reaction. This may include bioremediation reactions, production of biofuels,
treatment of sludge, etc.
[0037] A method of accelerating decomposition in a compost heap is
provided. The method comprises providing a compost device having
appropriate environmental factors such as soil, moisture, air, bacteria and/or
worms, inserting waste material into the compost device and applying
ultrasonic vibration to the device. The method of the present invention can be
easily adapted to various types of composters currently on the market.
[0038] A single transducer can be used for a maximum effect. For industrial
scale composting, it may be desirable to have more than one transducer. If
more than one transducer is used, they should produce a constructive wave.
The position of the transducer can be varied without altering the
effectiveness
of the method.
[0039] Good results can be obtained using a wide range of frequencies. For
optimal results, a strong ultrasonic field is required and the energy produced
by the transducers is transmitted into the liquid containing waste material.
Ultrasonic waves having a frequency from about 1 to about 10,000 kHz can
be used in the method and device of the present invention. More preferably
about 25 to 500 kHz waves are used.
[0040] The effect of ultrasonic vibration on the rate of decomposition was
assessed using various types of vegetable matter. Specific methods are
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discussed in the Examples below. The rate of decomposition can be
determined by analyzing the weight of the waste material. As waste is
decomposed and water and gas are formed, the weight of the waste is
decreased. Application of ultrasonic vibration significantly increased the
rate
of decomposition as compared to non-treated waste. The ultrasonic
treatment is particularly effective at the early stages of decomposition. By
accelerating the rate of decomposition, more waste can be processed in a
shorter time. This provides significant benefits at both the household and
industrial level. As shown in Figures 4A, B, and C and discussed further in
the examples below, cabbage is decomposed at a significantly faster rate in
the presence of ultrasonic vibration. Figure 4A illustrates that the total
weight
decreases more rapidly in the sample treated with ultrasonic vibration. The
effect is especially important at the early stages as shown in Figure 4B.
Figure 4C illustrates the decrease in terms of % weight loss. The untreated
sample takes 36 hours longer to reach the same stage. These results indicate
that applying ultrasonic waves significantly increases the rate of production
of
compost. Thus, more waste can be processed in a shorter time.
[0041 ] The rates of production of compost from the decomposition of carrot
(Figure 5) and onion (Figure 6) are also significantly enhanced by ultrasonic
treatment. The results demonstrate that the method can be applied to
various types of organic material and the efficiency of composting can be
significantly increased by the methods of the present invention.
[0042] The above disclosure generally describes the present invention. It is
believed that one of ordinary skill in the art can, using the preceding
description, make and use the compositions and practice the methods of the
present invention. A more complete understanding can be obtained by
reference to the following specific examples. These examples are described
solely to illustrate preferred embodiments of the present invention and are
not
intended to limit the scope of the invention. Changes in form and substitution
of equivalents are contemplated as circumstances may suggest or render
expedient. Other generic configurations will be apparent to one skilled in the
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art. Documents such as patents or patent applications referred to herein are
hereby incorporated by reference.
EXAMPLES
[0043] Although specific terms have been used in these examples, such
terms are intended in a descriptive sense and not for purposes of limitation.
Methods of microbiology and physics referred to but not explicitly described
in
the disclosure and these examples are reported in the scientific literature
and
are well known to those skilled in the art.
Example 1. Controlled composting of cabbage
[0044] A cabbage was cut into strings and divided in two. The control (A) was
placed in lukewarm water. The treated half (B) was placed in an ultrasonic
bath for one hour. The samples were then placed in sealed plastic bags along
with moist soil. The starting amounts were as follows:
TABLE 1
A (g) B (g)
(reference) (ultrasonic)
cabbage (g) Original 10.397 10.425
soaked with water for 1 hour 11.370 11.560
Soil (g) original, non-dry 157.709 157.420
total (g) 169.079 168.980
TABLE 2
[0045] The samples were inspected and weighed at various time points and
the percent weight loss was recorded. The results are shown below:
time elapsed weight loss %
Memo A (g) B (g)
(h:m:s) A B
0:00:00 169.079 168.980 0.000 0.000
58:40:00 168.955 168.760 0.073 0.130
134:00:00 bag opened 168.701 168.452 0.224 0.312
160:00:00 bag opened 168.571 168.351 0.300 0.372
227:00:00 bag opened & shaken up 168.242 168.023 0.495 0.566
279:30:00 bag opened & shaken up 167.970 167.725 0.656 0.743
447:50:00 bag opened & shaken up 167.583 167.312 0.885 0.987
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514:00:00 bag opened 167.426 167.156 0.978 1.079
[0046] The percent weight loss correlates with decomposition as the
vegetable matter is transformed into compost, methane and water. In the first
three days, the majority of the cabbage was decomposed.
[0047] Since vegetables comprise mainly water (>90%), a weight decrease of
about 1% is a significant indicator of the decomposition rate. As shown in
Figures 4A, 4B and 4C, the majority of the decomposition occurs in the first
few days with the ultrasound treated sample having an accelerated rate of
decomposition.
Example 2. Controlled decomposition of carrot
[0048] Carrots were cut into strings and divided into two samples. One sample
(A = control) was placed in lukewarm water for one hour. The second sample
(B = experimental) was placed in a 35kHz ultrasonic bath for one hour. The
samples were then placed in separate sealed plastic bags together with moist
soil. The samples were stored at 30'C. The starting amounts were as follows:
TABLE 1
A (g) B (g)
(reference) (ultrasonic)
Carrot (g) Original 20.354 20.129
soaked with water for 1 hour 20.394 20.232
Soil (g) original, non-dry 167.426 167.156
total (g) 187.144 186.866
[0049] The samples were examined and the amount of weight loss was
measured at various times. The results are shown below:
TABLE 2
time elapsed Memo A(g) B(g) weight loss %
(h:m:s) A B
0:00:00 carrot inserted, well shaken 187.144 186.866 0.000 0.000
21:26:00 186.944 186.643 0.107 0.119
67:40:00 186.152 185.791 0.530 0.575
95:59:00 185.826 185.298 0.704 0.839
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119:28:00 A: still identifiable 185.435 184.814 0.913 1.098
B: mostly gone
167:33:00 A: mold, very wet (clay) 185.082 184.328 1.102 1.358
B: no mold, almost all gone
226:55:00 A: still identifiable 184.771 183.890 1.268 1.593
B: hard to identify
[0050] The results are shown graphically in Figure 5. It is clearly apparent
that
the rate of decomposition is accelerated in the ultrasonic treated sample.
Example 3. Controlled decomposition of onion
[0051] The onion was cut into thin slices and the segments separated. The
onion was divided into two samples. The first "control" sample (A) was placed
in lukewarm water for an hour. The second "experimental" sample was put in
an ultrasonic bath for one hour. Each sample was then placed in a sealed
plastic bag along with some moist soil. The starting concentrations were:
TABLE 1
p- (g) B (g)
(reference) (ultrasonic)
Onion (g) Original 20.470 20.174
soaked with water for 1 hour 20.179 20.202
soil (g) original, non-dry 159.946 159.979
total (g) 179.933 180.020
[0052] The samples were examined and the weight was recorded as various
times. The results are shown below:
TABLE 2
time elapsed weight loss %
(h:m:s) memo A(g) B (g) A B
0:00:00 onion inserted, well shaken 179.933 180.020 0.000 0.000
21:35:00 179.751 179.806 0.101 0.119
67:40:00 179.248 179.228 0.381 0.440
96:06:00 178.917 178.868 0.565 0.640
119:29:00 A: white, identifiable 178.553 178.494 0.767 0.848
B: small, separated
167:40:00 A: mold, some left 178.232 178.091 0.945 1.072
B: no mold, All gone
179:00:00 A: still some identifiable 177.905 177.778 1.127 1.245
B: not identifiable
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[0053] The results are shown graphically in Figure 6. As can be seen from the
diverging lines, the rate of decomposition is accelerated in the sample
pretreated with ultrasound.
[0054] The present invention has been described with regard to one or more
embodiments. However, it will be apparent to persons skilled in the art that a
number of variations and modifications can be made without departing from
the scope of the invention as defined in the claims.
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