Note: Descriptions are shown in the official language in which they were submitted.
CA 02269043 1999-04-14
METHOD FOR DISPOSING FOOD WAS~fES AT LOW AND ORDINARY
TEMPERATURES USING MICROBES AND APPARATUS THEREFOR
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a method for disposing food wastes at low and
ordinary temperatures using microbes and to an apparatus therefor. More
particularly, the
present invention relates to a method for disposing food wastes completely and
cleanly with
producing little offensive odor.
Description of the Prior Art
Food wastes are organic masses which can be almost completely decomposed to
the
dregs if there are given appropriate conditions such as temperature and oxygen
supply. For
.example, because food wastes, consisting mainly of C, H, N and O, provide
nutrients to
microorganisms, if the organic wastes are put in a certain apparatus or place
in which various
microorganisms are abundant under an appropriate condition, the wastes can be
converted
finally into building blocks or end products such as COz, HzO, NOz, and the
like. Thus, even
though food wastes are daily discarded in a certain place or apparatus, no
heaps of wastes are
found therein for a significant period of time.
when condition factors, such as temperature, oxygen, nutrition and th.e like,
are
appropriately provided, microbial populations undergoing balanced growth
increase about
2 fold in a period of time. After this exponential phase, they excrete encymcs
outside cells.
These extraccllular enzymes (exo-enzymes) are inactivated after they fiu~ction
to decompose
2 5 macromolecules into smaller ones suitable to be digested by the microbes.
Because enzymes
are necessary for microbes to grow and proliferate, they are continuously
expressed during
the growth of microbes. Thus, microbus can be used to easily dispose food
wastes without
producing pollution.
Organic matters are generally decomposed aerobically or anaerubicalJy
according to
1
CA 02269043 1999-04-14
the fermentation patterns of enzymes. Aerobic fermentation does not produce
offensive
odors, but is slow in speed. On the other hand, anaerobic fermentation
produces a large
quantity of gas, giving out an offensive odor, but leads to rapid catabolism.
SUMMARY Ql THE INVENTION
With the background in mind, the present invention has an object to provide a
method
for disposing food wastes cleanly.
Another object of the present invention is to provide an apparatus in which a
large
quantity of food wastes are disposed continuously and cleanly.
In accordance with an aspect of the present invention, there is provided a
method for
disposing food wastes at low and ordinary temperatures, comprising the steps
of: co-
cultivating active aerobic and facultative bacteria are co-cultured on sterile
dry carriers;
feeding into an apparatus containing the carriers a predetermined amount o.f
food wastes a
day for six months; and mixing the carriers with the food wastes fed, at a
regular interval at
a temperature of 25-35 °C, whereby the food wastes are decomposed for 6
months by the
fermenting and/or oxidizing action of the bacteria on the carriers.
In accordance with another aspect of the present invention, there is provided
an
apparatus for disposing food wastes at low and ordinary temperatures,
comprising: a
2 0 container made of a heat insulating material; a fermenting tank with a
waste drop and a
hexagonal axis, the waste drop being opened and closed by a lid with the aid
of a spring type
holder so as not to shock the fermenting tank, the hexagonal axis extending
through the
fermenting tank and having six stirring wings on each of which 2 wssistant
wings with a cross
section of a are mounted, the stirring wings being arranged at an angle of 60
° with
2 S additional adjacent wings and functioning to mix the food wastes, along
with the assistant
wings; and a deodorizing means with an exhaust pipe, the fermenting tank anil
the
deodorizing mans being installed inside the container, wherein the food wastes
can be
completely decomposed with producing little offensive odor.
2
CA 02269043 1999-04-14
BRIEF DESCRIPTION OF THE DRAWINGS
'fhe above and other objects and aspects of the invention will become apparent
from
the following description of embodiments with reference to the accompanying
drawings in
which:
Fig, 1 is a partially broken perspective view showing the apparatus of the
present
invention;
Fig. 2 is a rear perspective view showing an apparatus mounting heating wires,
according to a first aspect of the present invention;
1 U Fig. 3 is a rear perspective view showing an apparatus mounting a fan
heater,
according to a second embodiment of the present invention;
Fig. 4 is a cross section showing the apparatus according to the first
embodiment,
taken along the li~.~e A-A'; and
Fig. 5 is a partially enlarged perspective view showing a fermenting tank
according
to the second embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention pertains to a method for cleaning food wastes by use of
microbes. The microbes are is saprophytic bacteria which exist ubiquitously in
soils, rivers
and streams. Available are those which can decompose organic matters, such as
carbohydrates, proteins, fats, starches, cellulose, etc. and preferable are
those which are
aerobic or facultative.
After being cultured in broth, the available bacteria are inoculated and co-
cultured
2 5 on carriers. As the carriers, sawdust, rice braes, peat, wood chips, and
porous ceramic balls
are useful. Prior to inoculation, the carriers are sterilized and dried to the
extent that they
contain a water content of. 10%.
These carriers are placed in a space which is maintained at a temperature of25-
35 °C,
and mixed with food wastes at a regular interval for a period of time. In this
course, the food
3
CA 02269043 1999-04-14
wastes are decomposed by the oxidizing eatd fermenting actions of the bacteria
co-cultured
on the carriers. For this regard, an apparatus is provided, which is equipped
with a
temperature controlling system, a mixing system, an air-supply system and a
deodorizing
system, in accordance wifh the present invention.
A better understanding of the present invention may be obtained through the
following examples which are set forth to illustrate, but are not to be
construed as the limit
of the present invention.
F~,~p _~~-yr_l~ction Qf Microbes
First Group (Aerobacter; Entcrobacter spp.): Selection was made for the
bacteria
which can oxidise the food wastes consisting mainly of C, H and O into carbon
dioxide and
water in the presence of oxygen molecules, as represented by (CHiO)x - COz +
.ELiO, and can
ferment them in the absence of oxygen molecules, as represented by (CHZO)x -
CH~COOH.
Second Group (bacillus spp.): During growth, the strains belonging to this
group
excrete exo-enzymes which decompose extracellular macromolecules into smaller
molecules
which are suitable to be transported inside the cells of their own or those of
other strains.
Examples of the exo-enzymes include lipases, proteases and amylaseb which
hydrolyze
lipids, proteins and starchES, respectively. Thus, the strains selected from
this group can
2 0 convert suspended solids, such as fats, proteins and starches, into
soluble suspended solids
which are now able to be utilized for intracellular digestion by microbes.
Third Group (Pseudomonas spp.): Like the first group bacteria, the bacteria of
this
group oxidize the food wastes consisting mainly of C, H, and O, into carbon
dioxide and
watE;r, as expressed by (CHzO)s - COs + H20. Besides, the instant bacteria can
decompose
2 5 the wastes resulting from petrochemical materials, such as HzS, hard
detergents (A13S), soft
detergents (LAS), N-hexane, phenol, hydrocarbon, etc.
Fourth Group (Cellulomonas spp.): The bacteria of. this genus hydrolyze
cellulose by
converting a-glycvsidic bonds into ~i-glycosidic bonds which are more easily
utilized by
bacteria.
4
CA 02269043 1999-04-14
r fifth Group (Rhodopseudomonas spp.): Under an aerobic condition, the instant
bacteria function like Pseudomonas bacteria, On the other hand, in the absence
of oxygen
molecules, the bacteria undergo a fermentative growth. Upon the fermentation,
the energy
source (CHzO)F is decomposed in two steps: (CHzO)x - CH,COOH; CH,COOH ~ CH, +
C02. Selection was made for the bacteria which tan restrain this two-step
fermentation and
perform the reaction CH3COOH - COz + H10. The selected strains could play am
important
role in removing the offensive odor factor, CHI gas.
Sixth Group (Nitrosomonas spp.) : When proteins are decomposed, ammonium (NH~-
N) is produced, '1 hese nitrifying bacteria oxidize ammonium to nitrite (1~0z-
N). This
oxidation must be performed in the presence of oxygen molecules as follows:
2NH, + 30z
- 2NOi' + 2HZ0 + 2I-I+.
Seventh Group (Nitrobacter spp.) : These nitrifying bacteria oxidize nitrite
(NOi-N),
a stable compound, further to nitrate (NO,-I~, playing an important role in
making the food
wastes valuable as fertilizers. Like Nitrosomonas, these bacteria actively
function at low and
ordinary termperatures under a weak aerobic condition as follows: 2NOi + OZ --
2N03 .
EXAMPLE Il: Co-Cultivation of Microbes on Carriers
Carriers, such as sawdust, rice bran, peat, wood chips and porous ceramic
balls, were
2 0 sterilised and dried so as to have a water content of 10%. On these
carriers were co-cultured
the microbes which belong to the 7 groups of Example II. These bacteria
carriers, sold under
the brand name "Bio-Chip", were used to dispose food wastes in an apparatus
which will be
described in Example III.
EXAMPLE III: Apparatus for Disposing Food Wastes at Low and Ordinary
Temperatures
The present invention provides an optimal apparatus in which the Bio-Chip, a
bacteria carrier on which various bacteria of Example I are cu-cultured, can
be used.
Usually, organic matters are decomposed faster under an anaerobic condition
than under an
5
CA 02269043 1999-04-14
aerobic condition. For example, the aerobic decomposition rate of organic
materials is 7
times higher than the anaerobic decomposition rate. With this in mind, the
present invention
utilized facultative bacteria. In addition, since anaerobic fermentation
produces otfensive
odorous gas, aerobic bacteria were also used. These bacteria are co-cultured
on a carrier
which i.s fed into the apparatus, along with food wastes.
The apparatus of the invention will be described in conjunction with the
accompanying drawings.
Refernng to Fis. 1, there is a partial broken perspective view of an apparatus
according to a ftrst embodiment of the present invention As shown in Fig. 1,
the apparatus
1 o comprises a container 2S made of a heat insulating material, a fermenting
tank 18 with a
wcste drop 1 which is opened and closed by a lid 3 with the aid of s spring
type holder 4, and
a deodorizing means S with an exhaust pipe 6, the fermenting tank 18 and the
deodorizing
means S being installed inside the container. A hexagonal axis 21 which
extends through
the fermenting tank 18, is fixed to the fermenting tank via a bearing fixing
adapter 9 and is
directly connected to a rotating gent 10 which rotates by the rotational power
transmitted via
a chain 11 from an operating gear 13 mounted in a motor 14. The tension of the
chain is
controlled by a tension roller 12.
Fig. 2 shows the apparatus in a rear perspective view. As shown in this
figure, the
fermenting tank 18 comprises a plurality of heating wires 29 on its surface to
maintain the
2 0 inside of the fermenting tank 18 at a predetermined temperature, for
example, 25-3S °C. Six
stirring wings, each having two assistant wings with a cross section of n, are
extended at an
angle interval of 60 ° from one circumference of the axis 21 with a
hexagonal cross section,
as shown in Fig. 4.
A second embodiment according to the present invention is shown in Fig. 3. In
this
2 5 embodiment, an air supply system comprising a fan heater 299 and a
blastpipe 300 is
provided instead of the heating wires 29 of Fig. 2.
With reference to Fig, 5, there is an enlarged view for a fermenting tank 18
of the
second embodiment, in which a plurality of air inlets 301 connected to the
blastpipe 300 are
established at a regular distance.
6
CA 02269043 1999-04-14
At an upper site of the fermenting tank 18, an exhaust gas filter 2 is
provided from
which the exhaust gas pipe 6 goes through the deodorizing means to an outer
surface in the
rear side of the container. Exhaust gas, such as COi, which is generated from
the food
wastes in the fermenting tank 18, is passed from the exhau9t gas tilter 2
through the exhaust
gas pipe 6 to the deodorizing means 5 in which offensive odors are removed by
its
neutrali2ing agent and an active carbon layer, and ventilated out along the
exhaust gas pipe
6. At another upper site of the fermenting tank 18, an air inlet 8 equipped
with a fan (not
shown) is provided to supply a necessary amount of air for the microbes within
the
fermenting tank 18.
Alternatively, the deodorizing means 5 may comprise a platinum-coated
honeycomb,
instead of the neutralizing agent and active carbon layer, to remove the
offensive odors
generated from food wastes.
Below, a detailed description will be given of the operation of the apparatus,
In order
to use the Bio-Chips of the invention, there is needed an apparatus for
decomposing food
wastes, such as that shown in Fig. 1. A minimum amo,ant of oxygen (air) is
supplied inside
the fermenting tank I 8 to ferment the food wastes fast and odorless(y. In
this regard, the $io-
Chips and the food wastes are mixed up for as short a time as possible, to
decompose; the
food wastes only with the air taken in. For example, a timer or a gear
operation may be used
in such a way that there is continuously repeated e~ 30 min cycle in which the
food wastes and
2 0 the Bio-Chips are mixed up for 5 min, followed by a pause for 25 min.
During the pause,
the decomposition of food wastes is rapidly proceeded by anaerobic microbes.
if the
decomposition is proceeded only in the absence of oxygen molecules, seriously
offensive
odors are produced. thus, anaerobic fermentation is rapidly induced just
before the time
when the decomposition is completely converted into an anaerobic type and
then, aerobic
2 5 fermentation is caused by mixing the food wastes for S min through a timer
or gear
operation.
Food wastes may contain water at an amount as much as 80-85 %. The water is
slowly consumed while being absorbed in the media of the Bio-Chips, such as
sawdust, ,peat,
wood chips, pomus ceramic balls, and the like. In the apparatus of the present
invention, the
7
CA 02269043 1999-04-14
temperature of the fennenting tank is maintained at 25-35 °C and may be
raised to 4U-45 °C
by the heat generated during fermentation, consuming the water. The
temperature at the
inside of the fermenting tank is increased rapidly during fermentation, but
slowly deuretr9ed
down to low or ordinary temperatures (35 °C or less) by a fan.
Fementation, a process in which microbes decompose organic materials, is
divided
into three types according to temperatures: tow temperature fermentation at 30
"C or less;
medium temperature fermentation at 30-45 °C; and a high temperature
fermentation at 45-60
°C. '.this high temperature fermentation needs a water-collecting means
because
fermentation is rapidly proceeded. In addition, the high temperature
fermentation compels
1 U organic materials to be rapidly decomposed into acetate, CH4, COz and/or l
IZS, producing
serious odors. Thus, a special deodorizing means is needed for the high
temperature
fermentation. In contrast, the low or medium temperature fermentation does not
produce
acetate, significantly responsible for the offensive odors generated upon the
fermentation of
food wastes. Some odors, which are inevitable, are completely removed by the
deodorizing
means 5 in the apparatus.
As mentioned, the acetate production process, its subsequent process (acetate
C1 L,+COz), and the HAS production process are restrained in the disposing
apparatus ofthe
present invention. Thus, by virtue of this odorless advantage, the apparatus
of the invention
can be installed inside or outside homes or eating establishments.
In order to uniformly mix up the Bio-Chips of the invention with waste foods,
a
stirring wing is extended from one side of the hexagonal axis 21. Thus, a
stirring wing forms
an angle of 60 ° with an additional adjacent wing. Assistant wings 20
with a cross section
of o are provided to the stirring wings to help with the mixing by th.e
stirring wings. The
assistant wings are also helpful in drawing out the Bio-Chips when resupplying
there.
2 5 As for the spring type holder 4, it functions to buffer the significant
weight of the lid
3, so as to absorb the shock which is provided to the fermenting tank by the
lid 3. Thus,
damage which may occur to the apparatus when the lid 3 is slammed, is
prevented by the
holder 4.
When the lid 3 is opened and closed, the mixing is automatically ceased and
started,
8
CA 02269043 1999-04-14
respectively. :In this regard, a limit switch 7 of a spring jag type is set at
a contact between
the lid 3 and the fermenting tank 18 and connected to the electric circuit fur
the mixing axis.
When the lid is opened to feed waste foods into the fermenting tank, if the
mixing continues
to be proceeded, an unpleasant scene is viewed and an offensive odor is
released. Therefore,
it is preferable that the mixing is ceased when the lid is opened.
Against a temperature drop in the inside ofthe fermenting tank l8, the heating
wires
29 or the fan heater 299 is mounted at the rear of the fermenting tank 18. For
example, when
it is cold, such as in winter weather, the heating wires or fan heater
automatically operates
to maintain the inside of the fermenting teak at a temperature of 25 °C
or higher. On the
other hand, at a temperature higher than 35 °C, only the fan of the fan
heater 299 or a
deodorizing fan (not shown) in the deodorizing means 5 is automarically
operated to lower
the temperature of the fermenting tank 18 to a preferred range,
In the low and ordinary temperature fermentation according to the present
invention,
the odor which is generated during the fermentation of food wastes is
restrained to as little
an extent as possible. However, since the odors that foods themselves have are
inevitable,
the deodorizing means 5 is provided. The odorous gas within the fermenting
tank enters the
exhaust sas filter 2 and flows through the exhaust pipe 6 to the deodorising
means 5 at which
odors are removed by the neutralizing agent and the active carbon layer, and
the odorless gas
is expelled through the exhaust pipe 6. Alternatively, a platinum catalyst
oxidizer system,
2 0 instead of the neutralizing agent and active carbon layer, may be used to
remove the odor.
Optionally, an instrument panel may be provided to detect the temperature and
humidity of the fermenting tank 18, the targeted temperature and humidity and
the practical
temperature and humidity of the platinum oxidizing catalyst system.
2 5 EXAMPLE IV ; process of Disposing Food Wastes Using the Apparatus
A disposing apparatus comprising a 700 liter fermenting tank was manufactured
according to the description of Example 3. This apparatus containing the
bacteria carriers,
~Bio-Chips, was set for 6 months .from 24 June, 1996 to 24 December, 1996 in a
miss
9
CA 02269043 1999-04-14
residential district in which there were 300 households. good wastes were fed
two or three
times into the apparatus at a total amount of 100 kg a day. A fermentation
cycle in which
mixing the food wastes was carried out for 5 min, followed by a Pause for 25
min, was
repeated while the fermenting tank was maintained at 25-35 °C.
During the fenncntation, a clean state was kept without the offensive odors,
such as
those attributed to HZS, CH, and acetate,
As described hereinbefore, the apparatus for disposing food wastes can
effectively
ttrmcnt food wastes at 25-35 °C in both the presence and abset<ce of
oxygen molecules, so
the food wastes can be decomposed rapidly while odors are little produced
during the
fermentation. Therefore, the present invention is very useful in the
environmental industry.
The present invention has been described in an illustrative manner, end it is
to be
understood the terminology used is intended to be in the nature of description
rather than of
limitation. Many modifications sod variations of the present invention are
possible in light
of, the above teachings. Therefore, it is to be understood that within the
scope of the
appended claims, the invention may be practiced otherwise than as specifically
described.
