WO2007075053A1

WO2007075053A1 - Method of resolving food waste using aerobic microorganism and apparatus therefor

Info

Publication number: WO2007075053A1
Application number: PCT/KR2006/005784
Authority: WO
Inventors: Dae-Ho Jang
Original assignee: Dae-Ho Jang
Priority date: 2005-12-27
Filing date: 2006-12-27
Publication date: 2007-07-05
Also published as: KR20060008851A; KR100722714B1

Abstract

A method of resolving food waste using aerobic microorganisms and an apparatus therefor are disclosed. The method comprises a microorganism input process S100, a microorganism culture process S200, a food waste input process S300 and a food waste decomposition process S400. The apparatus comprises a mixing basin 10, a plurality of nozzles 54, a mixing shaft 13, a mixing blade 30, a discharge guide 40, a heater 50, a hot water jacket 51, a first rinsing nozzle 41, a second rinsing nozzle 42, a humidity adjustment and deodorization means 600, a heat-keeping member 7, and a frame 70.

Description

METHOD OF RESOLVING FOOD WASTE USING AEROBIC MICROORGANISM AND APPARATUS THEREFOR

Technical Field

[1] The present invention relates to a method of resolving food waste organic matter using aerobic microorganisms and an apparatus therefor. More particularly, the present invention relates to a method of resolving food waste using aerobic microorganisms, comprising (1) cutting, softening and grinding organic matter so that microorganisms can rapidly approach the organic matter and thus the organic matter can be easily decomposed, (2) rapidly mixing the organic matter, and (3) putting the microorganisms under optimum conditions for activation of the microorganisms, and an apparatus therefore. The method helps effectively decompose food waste into inorganic matter and terminate it by natural purification in a short period, and thus the food waste is returned to nature, resulting in a decrease of environmental pollution by food waste. Background Art

[2] Organic waste, represented by food waste, is looming large as the biggest environmental pollution problem of the 21st century. For the disposal of food waste in Korea, a landfill method has been used for several decades to date. However, the landfill method causes many problems, such as ground water pollution by leachate and air pollution by hazardous gases, because a variety of pollutants is generated while implementing the landfill method.

[3] The Korean government, recognizing such problems, totally banned the landfill of food waste as of January 1, 2005. As of that day, households are obliged to separate waste into a plurality of categories before disposing of it. Further, restaurants with working areas of 125 m or more, traveler accommodations having group cafeterias holding 100 people or more, and large-scale shops having working areas of 3000 m or more, such as Agricultural and Marine Products Center, are also obliged to reduce food waste by themselves before discharging. According to the legislation, if such obligations are breached, imprisonment of up to three years or a heavy fine of up to 20,000,000 won can be imposed on violators (Clause 3, Article 15 of Waste Management Act and Article 9(2) of Regulations of the Act).

[4] Every day, as much as 1000 tons of food waste causes the waste of resources worth about 14 trillion won, which is enough to build two airports the size of Incheon Airport. Accordingly, the government has made great efforts to recover food waste into compost or feedstuff. However, such efforts of the government have been in vain, and rather produce different kinds of waste because efficient treatment technologies for disposing of food waste have not been developed yet. As a result, the disposal of food waste, which will continue to be generated, is becoming a big problem.

[5] Nowadays, methods of disposing of food waste are classified into recovery and resolution by producer responsibility. Under the circumstances in Korea, which suffers from a lack of resources, the recovery method is preferable. However, since the recovery of food waste requires large-scale facilities and incurs a high cost, general households or restaurants and caterers cannot afford to install apparatus for implementing the recovery method. Accordingly, food waste is carried to a food waste treatment area at which the recovery apparatus is installed. However, it is difficult to recover food waste containing 80 to 85% moisture because the food waste easily rots, and thus generates an offensive odor and waste water during transportation of the food waste. Further, food waste has been found to be hard to compost due to the high salt content. Still further, feed processes for recycling the food waste are also difficult to implement due to the lack of improved technologies. Even though the food waste was recycled into feedstuff, such recycled feedstuff has not been accepted by farmers. Even though the government tries to improve the quality of the feedstuff, there has been no noteworthy solution.

[6] Thanks to such problems, the government legislated treatment under Extended

Producer Responsibility (EPR). In particular, the producer resolution method is attracting the attention of relevant business parties as a new technology and experts are making predictions that the producer resolution apparatus will create a market worth 100 billion won or more and that apparatuses required for implementing the producer resolution method will be installed in every household as a necessity. Thus, a lot of entrepreneurs quickly established companies without clear technical solutions and commercialized faulty apparatuses, thus cheating customers and discrediting themselves in this business area, so that the existence of this field is endangered.

[7] The conventional food waste resolution treatment apparatus has a mixing blade having a flat spoon shape, reflecting the low level of technology, so that it is impossible to treat organic matter in its original form, that is, uncooked food waste such as green onions, radishes and cabbage. Further, the conventional food waste resolution treatment apparatus is limited with respect to treatment period and capacity of food waste because an environment for sustaining microorganisms is not carefully maintained. Still further, the conventional food waste resolution treatment apparatus cannot be smoothly used because it has many faults, that is, the apparatus frequently stops due to overloading since food waste is apt to become stuck between mixing blades and the mixing basin.

[8] Further, according to the conventional technologies, in the case of decomposing food waste using microorganisms, due to apparatuses manufactured without consideration of the characteristics of, or optimum survival conditions for, microorganisms, the activation of microorganisms is insufficient, and thus food waste cannot be effectively decomposed. Still further, since a water layer is formed on the surface of food waste by mucous matter comprised of glucose and peptin generated during digestion and decomposition processes by microorganisms, oxygen is blocked, so that the microorganisms perish.

[9] Since the conventional food waste resolution treatment apparatus operates at a temperature that is lower than the solidifying point of fat matter, such as lard (the solidifying point of which is 28-48⁰C) and beef tallow (the solidifying point of which is 36-5O⁰C), the fat matter solidifies in mixing basins and drains. As a result, organic matter other than the fat matter is prevented from being decomposed, microorganisms perish, and the disposal of food waste is impeded. These problems are more severe in the winter season.

[10] Yet further, since the conventional food waste resolution treatment apparatus has a very short resting period, aerobic microorganisms do not move but remain still when mixing and pulverizing are continuously performed, because they are living things. Accordingly, digestion and decomposition are extremely limited, and thus the efficiency of the apparatus is very low. These problems are caused because the survival environment of microorganisms is not carefully maintained. Disclosure of Invention

Technical Problem

[11] Accordingly, the present invention has been devised in consideration of the aforementioned problems and situations, and it is an object of the present invention to provide a method of resolving food waste and organic matter using aerobic microorganisms, and an apparatus therefor. The method of resolving food waste using aerobic microorganisms comprises (1) cutting, softening and grinding organic matter so that microorganisms can rapidly approach the organic matter, and thus the organic matter can be easily decomposed, (2) rapidly mixing the organic matter, and (3) putting the microorganisms under optimum conditions for activation of the microorganisms. The method helps effectively decompose food waste into inorganic matter and terminate it by natural purification in a short period, and thus the food waste is returned to nature, resulting in decreased environmental pollution due to food waste. Technical Solution

[12] In order to achieve the above described advantageous effects and objects, in accordance with the present invention, there is provided a method of resolving food waste (organic matter) into inorganic matter using aerobic microorganisms, comprising: a microorganism input process SlOO for inputting wood chips 2, having grain sizes of 4 to 8 millimeters, into a mixing basin heated to a temperature in the range from 25 to 55⁰C and surrounded by a heater 50 to occupy 35 to 45 volume% of the total volume of the mixing basin 10, and inputting microorganisms in liquid form into the mixing basin 10 by an amount proportional to the capacity of the mixing basin 10; a microorganism culture process S200 for culturing microorganisms, in which a mixing and pulverizing period, in which mixing and pulverizing are performed by a mixing blade 30 installed at a center portion of the mixing basin 10, and a resting period are repeated for 8 to 12 hours while hot water 6 having a temperature in the range from 30 to 6O⁰C is periodically sprayed using nozzles 54 from an upper portion of the mixing basin 10; a food waste input process S300 for inputting food waste 3 into the mixing basin 10 through an opening after opening a cover 71 until the food waste occupies 45% of the total volume of the mixing basin 10; a food waste decomposition process S400 for mineralizing the food waste 3 into inorganic matter, in which mixing and pulverizing periods, in which mixing and pulverizing are performed by the mixing blade 30 installed at the center portion of the mixing basin 10, and resting periods are repeated for 10 to 14 hours while hot water 6 at a temperature in the range from 30 to 6O⁰C is periodically sprayed using the nozzles 54 from an upper position on the mixing basin; an oxygen supply and humid air discharge process S500, performed at the same time as all of the above processes, for supplying a sufficient amount of oxygen into the mixing basin 10 and purging humid air in the mixing basin, by forcedly introducing external dry air into the mixing basin using a blower or a fan 61 through an air input hole 62 formed at an upper portion of a first side of the mixing basin so that the humid air in the mixing basin is pushed and exhausted out through an overflow discharge hole 63 formed in an upper portion of a second side of the mixing basin, wherein the food waste input process S300 and the food waste decomposition process S400 are conducted again 5 hours have passed from the beginning of the food waste decomposition process S400.

[13] The microorganism culture process S200 and the food waste decomposition process

S400 may preferably comprise: a spraying and mixing process S600 for mixing and pulverizing the food waste using the mixing blade 30 while spraying hot water 6 using the nozzles 54; a mixing process S700 for mixing and pulverizing the food waste using the mixing blade 30 without spraying hot water 6; a rinsing process S800 for rinsing the food waste and a perforated portion, disposed in the lower part of the mixing basin 10, by discharging liquid containing inorganic matter falling to the bottom of the mixing basin 10 via a discharge guide 40, and by simultaneously rinsing the perforated portion 12 of the mixing basin 10 using a first rinsing nozzle 41 and a second rinsing nozzle 42; and a resting process S900 for allowing the microorganisms to be cultured and to actively decompose by stopping the mixing and the rinsing.

[14] The method may be driven by a low level step, a middle level step, and a high level step, in which periods of the mixing and spraying process S600, the mixing process S700, the rinsing process S800, and the resting process S900 are set to be 1 minute, 10 minutes, 30 seconds and 60 minutes, respectively, and the temperature of the hot water is set to be 6O⁰C in the low level step; periods of the mixing and spraying process S600, the mixing process S700, the rinsing process S800, and the resting process S900 are set to be 1 minute 30 seconds, 15 minutes, 40 seconds and 60 minutes, respective Iy, and the temperature of the hot water is set to be 6O⁰C in the middle level step; and periods of the mixing and spraying process S600, the mixing process S700, the rinsing process S800, and the resting process S900 are set to be 3 minutes, 10 minutes, 40 seconds and 60 minutes, respectively, and the temperature of the hot water is set to be 6O⁰C in the high level step.

[15] According to another aspect of the present invention, there is provided an apparatus for resolving food waste (organic matter) into inorganic matter using aerobic microorganisms, comprising: a mixing basin 10 having a perforated portion 12 at a lower part thereof; a plurality of nozzles 54 coupled to a first water pipe 52 installed to extend in a longitudinal direction at an upper portion of the mixing basin, the nozzles having certain angles and intervals therebetween, for spraying water in a plurality of directions; a mixing shaft 13 having a first end and a second end combined with bearings 11 installed in the mixing basin 10, either the first end or the second end penetrating the bearing 11 and being connected to an attenuation gear 21 and a driving motor 20; a mixing blade 30 including a plurality of bars extending from the mixing shaft 13 in a direction perpendicular to the mixing shaft and a plurality of blades provided to end portions of the bars for mixing and pulverizing wood chips 2 and food waste 3; a discharge guide 40 installed to surround the perforated portion 12 of the mixing basin 10 and to be inclined relative to the vertical direction; a heater 50 surrounding a semi-cylindrical lower part of the mixing basin 10 and having a predetermined length and width; a heat-keeping member 7 surrounding the mixing basin 10, the heater 50 and the discharge guide 40 for maintaining the internal temperature of the mixing basin; a controller 80 installed at one side of the mixing basin 10 and having a manipulator 81 connected to the driving motor 20, the nozzles 54, the heater 50, and the fan 62 for controlling the overall operation of the apparatus using the manipulator; and a frame 70 enclosing all of the above-described elements therein and having a cover 71 at an upper portion thereof and a wheel 72 at a lower side thereof; and further comprising: a hot water jacket 51 disposed to be in contact with one side of the mixing basin 10, bring water, supplied through a water supply pipe 55, into contact with the heater 50, and having a bar-type heater 56 therein, for supplying hot water 6 to a first water pipe 52 and a second water pipe 53; a first rinsing nozzle 41 and a second rinsing nozzle 42, the first rinsing nozzle disposed at the highest portion of the discharge guide 40, which is inclined to receive the hot water 6 via the second water pipe 52 and spray the hot water 6 to locations having gentle slopes, the second rinsing nozzle disposed at the same position as the first rinsing nozzle 41 and spraying the hot water 6 toward the entire surface of the perforated portion 12; an oxygen supply and humid air discharge unit 60 including a blower or a fan 61 for blowing external dry air into the mixing basin 10 through an air input hole 62 formed in the upper portion of the first side of the mixing basin in order to sufficiently supply oxygen into the mixing basin, and an overflow discharge hole 63 formed in the upper portion of the second side of the mixing basin to allow humid air in the mixing basin to be discharged therethrough by being pushed by the introduced external dry air.

[16] The mixing blade 30 may comprise: a plurality of bars 31 extending from the mixing shaft 13 in a direction perpendicular to the mixing shaft; a plurality of first mixing blades 32, each helically extending from the center portion of each of the bars in one direction with respect to the mixing shaft 13 for shifting a mixture of the wood chips 2 and the food waste 3 in a first direction while rotating together with the mixing shaft 13; a plurality of second mixing blades 33, each helically extending from an end portion of each of the bars 31 in a direction opposite the direction of the first mixing blade 32 for shifting the mixture of the wood chips 2 and the food waste 3 in a second direction, which is opposite the first direction, by rotating along with the mixing shaft 13; and a plurality of first pulverizing blades 34, each extending along each of the bars 31 from the first mixing blade 32 to have a predetermined width for pulverizing the mixture by rotating along with the mixing shaft 13; wherein the first mixing blade 32 and the second mixing blade 33 are symmetrically arranged with respect to the middle portion of the mixing shaft 13, and the first mixing blade 32 has a pushing area larger than that of the second mixing blade 33 which has a relatively large size in comparison with the first mixing blade 33 in order to balance the amount of shifted mixture of the food waste 2 and the wood chips 3.

[17] The rotation direction of the mixing blade 30 may be determined in a manner such that the mixture is moved toward the center of the mixing basin by the rotation of the first mixing blade 32.

[18] The mixing blade 30 may comprise: a plurality of bars 35, each extending from the mixing shaft 13 in a direction perpendicular to the mixing shaft, and adjacent bars having a predetermined angle between them; a plurality of first mixing bars 37, each extending from one end of each of the bars 35, having a predetermined length in the direction in which the mixing shaft 13 extends, and each being provided with a hook 36 at an end thereof, for mixing the mixture of the wood chips 2 and the food waste 3 by being rotated by the mixing shaft 13; a plurality of pulverizing rings 38 surrounding each of the first mixing bar 37 and moving back and forth, but not becoming separated from the first mixing bar due to the hook 36; and a plurality of second mixing bars 39, each extending from the mixing shaft 13 in a direction perpendicular to the mixing shaft but opposite the direction of the first mixing bar 37, and having an end with an arc shape.

[19] The mixing shaft 13 may be eccentric to one side of the mixing basin 10 in a longitudinal direction thereof, and thus the end of the first mixing bar 37 may be nearly in contact with the surface of the wall of the mixing basin 10, with a predetermined distance therebetween, when the first mixing bar is rotated, and the distance may be in the range from 1 to 3 millimeters.

Advantageous Effects

[20] According to present invention, when food waste is resolved using aerobic microorganisms, food waste is chopped, softened and ground in order to allow the microorganisms to rapidly approach the food waste, so that the food waste can be resolved in a short period, mixing is rapidly accomplished, and an optimum environment for the growth and activation of microorganisms is provided to the microorganisms. Accordingly, the present invention can maximize the efficiency of natural purification, so that food waste, including food waste generated when preparing material for cooking, is effectively resolved into inorganic matter in a short period and is returned to nature. Still further, the present invention has advantageous effects such that food waste is treated and resolved at a producer s site, so that plastic bags for collecting food waste are not necessary, there is no mess resulting from the collection and transportation of food waste to a food waste treatment site, offensive odors are not generated, maintenance cost is low, and environmental pollution is reduced. Brief Description of the Drawings

[21] FIG. 1 is a block diagram illustrating a method of resolving food waste according to one embodiment of the present invention;

[22] FIG. 2 is a perspective view illustrating the internal structure of an apparatus for resolving food waste according the first embodiment of the present invention;

[23] FIG. 3 is a front plan view illustrating the internal structure of the apparatus for resolving food waste according to the first embodiment of the present invention;

[24] FIG. 4 is a perspective view illustrating mixing blades of the apparatus for resolving food waste according to the first embodiment of the present invention;

[25] FIG. 5 is a perspective view illustrating mixing blades of an apparatus for resolving food waste according to the second embodiment of the present invention; and

[26] FIG. 6 is a side view illustrating a rinse nozzle and a hot water jacket. Best Mode for Carrying Out the Invention

[27] Hereinafter, a method of resolving food waste using aerobic microorganisms and an apparatus therefor according to embodiments of the present invention will be described with reference to the accompanying drawing.

[28] FIG. 1 is a block diagram illustrating a method of resolving food waste according to one embodiment of the present invention, FIG. 2 is a perspective view illustrating the internal structure of an apparatus for resolving food waste (food waste resolution treatment apparatus) according to the first embodiment of the present invention, FIG. 3 is a front plan view illustrating the internal structure of the apparatus for resolving food waste according to the first embodiment of the present invention, FIG. 4 is a perspective view illustrating mixing blades of the apparatus for resolving food waste according to the first embodiment of the present invention, FIG. 5 is a perspective view illustrating mixing blades of an apparatus for resolving food waste according to the second embodiment of the present invention, and FIG. 6 is a side view illustrating a rinse nozzle and a hot water jacket.

[29] The method of resolving food waste using aerobic microorganisms comprises a microorganism input process SlOO, a microorganism culture process S200, a food waste input process S300 and a food waste decomposition process S400.

[30] Microorganisms capable of decomposing food waste are classified into aerobic microorganisms (aerobes) and anaerobic microorganisms (anaerobes) according to the temperature at which the microorganisms grow. Aerobic microorganisms actively perform decomposition at temperatures in the range from 20 to 55⁰C, and microorganisms actively performing decomposition at temperatures lower than 2O⁰C or higher than 55⁰C are called anaerobic microorganisms. Among aerobic microorganisms, it is known that microorganisms which actively decompose organic matter at temperatures in the range from 45 to 55⁰C have high decomposition capacity.

[31] The microorganism input process SlOO is a process for inputting wood chips having grain sizes of 4 to 8 millimeters into a mixing basin 10 surrounded by a heater 50 and heated up to 25 to 55⁰C, at which aerobic microorganisms actively decompose organic matter, by 35 to 45 volume% compared to the total volume of the mixing basin 10, and aerobic microorganisms in liquid form are input into the mixing basin 10, the input amount thereof being proportional to the volume of the mixing basin 10. In the conventional method, microorganisms are periodically input, such as once a month, for providing an optimum environment for the survival and activation of microorganisms. However, the present invention has improved the microorganism input process, so that it is enough to put microorganisms into the mixing basin only once at the initial stage of the food waste decomposition method, and are supplemented 1 or 2 times a year. [32] The microorganism culture process S200 is a process in which mixing and pulverizing by mixing blades installed in the center portion of the mixing basin 10, and resting are repeatedly performed for 8 to 12 hours while hot water 6 having temperature in the range from 30 to 6O⁰C is sprayed into the mixing basin 10 in every direction through nozzles. The temperature of the supplied hot water is set to be slightly higher than optimum temperature, that is, it is set to be in the range from 30 to 6O⁰C because the temperature of the hot water is lowered by about 5⁰C when the hot water is supplied to microorganisms due to natural heat loss occurring during the process. On the other hand, the conventional method uses cold water, but the method according to the present invention uses hot water 6 having a temperature appropriate for the survival and the characteristics of the microorganisms in order to provide the microorganisms with an optimum environment.

[33] The food waste input process S300 is a process for inputting food waste into the mixing basin 10 through an opening, provided at an upper portion and a front side of a frame 70 of the mixing basin 10 and covered by a cover 71, in an amount of 45 % of the total volume of the mixing basin 10.

[34] The food waste decomposition process S400 is a process for mineralizing the organic matter in the food waste 3 into inorganic matter by repeating mixing and pulverizing by the mixing blades 30 installed at the center portion of the mixing basin 10 and resting for 10 to 14 hours while simultaneously rinsing mucous matter, formed by the microorganisms, by periodically spraying the hot water 6, having temperature in the range from 30 to 6O⁰C, in many directions using nozzles into the mixing basin 10.

[35] The oxygen supply and humid air discharge process S500 is performed almost simultaneously with the above-described processes. During the oxygen supply and humid air discharge process S500, external dry air is introduced into the mixing basin 10 through an air input hole 62 provided in the upper portion of the first side of the mixing basin 10 using a blower or a fan 61, and humid air in the mixing basin 10 is exhausted by being pushed by the introduced dry air through an overflow discharge hole 63 provided in the upper portion of the second side of the mixing basin 10. That is, generally, vapor is formed due to heat generated by hot water 6 sprayed into the mixing basin 10 and by the digestion and decomposition reactions of food waste by aerobic microorganisms, and this vapor then condenses. When the vapor condenses, water drops fall onto the mixture 2 of the food waste 3 and the wood chips 2, so that a water layer forms on the mixture 2. This water layer blocks the supply of oxygen to the microorganisms, resulting in the death of the microorganisms. According to the embodiment of the present invention, in order to supply a sufficient amount of oxygen to microorganisms, the number of which increases geometrically, a blower or a fan 61 is used to forcedly introduce oxygen into the mixing basin, and humid air and offensive odors in the mixing basin are discharged through the overflow discharge hole 63. Thanks to the oxygen supply and humid air discharge process S500, the humidity of air in the mixing basin is adjusted, and oxygen can be continuously supplied to the microorganisms, so that the formation of the water screen is prevented and de- odorization is performed, and thus the apparatus for implementing the food waste resolving method can be smoothly operated.

[36] Further, the cover 71 installed at the upper portion of the mixing basin 10 is provided with a rubber packing 711 disposed on the inner surface of the cover 71 in order to prevent the food waste odor from entering indoor areas, resulting in an improvement of the environment in which the apparatus is installed.

[37] Thanks to the food waste decomposition process S400, most organic matter and food waste is decomposed 5 hours after the beginning of the food waste decomposition process S400, and only a small amount of food waste containing lime remains. Accordingly, new food waste can be additionally input into the mixing basin 10 5 hours after the beginning of the food waste decomposition process S400. That is, the food waste input process S300 can be performed again.

[38] The microorganism culture process S200 and the food waste decomposition process

S400 are further classified into a spraying and mixing process S600, in which food waste is mixed and pulverized by the mixing blades 30 while hot water 6 is sprayed onto the food waste through the nozzles 54 from the upper portion of the mixing basin 10, a mixing and pulverizing process S700, in which the food waste is mixed and pulverized by the mixing blades 30 without spraying hot water 6, a rinsing process S 800, in which an aqueous solution containing inorganic matter dropped onto the bottom of the mixing basin 10 is discharged via a guide 40, and a perforated portion 12 disposed at a lower portion of the mixing basin 10 is rinsed using a first rinsing nozzle 41 and a second rinsing nozzle 42, and a resting process S900, in which mixing and rinsing are stopped while the aerobic microorganisms are cultured and actively perform decomposition. The resting process S900 is the most important of the processes. The microorganisms stop their activity and perform very little decomposition and digestion if mixing and pulverizing are continuously performed, because they are living things. Accordingly, in consideration of this characteristic of the microorganisms, the period of the resting process S900 is set to be longer than that of the mixing and pulverizing process, so that the mineralization of food waste effectively progresses.

[39] Periods of the mixing and rinsing process S600, the mixing process S700, the rinsing process S800 and the resting process S900, and the temperature of the hot water are different for several level steps. In a low level step, periods of the mixing and rinsing process S600, the mixing process S700, the rinsing process S800 and the resting process S900 are set to be 1 minute, 10 minutes, 30 seconds, and 60 minutes, respectively, and the temperature of the hot water used in this step is set to be 6O⁰C. In a middle level step, periods of the mixing and rinsing process S600, the mixing process S700, the rinsing process S 800 and the resting process S900 are set to be 1 minute and 30 seconds, 15 minutes, 40 seconds, and 60 minutes, respectively, and the temperature of the hot water is set to be 6O⁰C. In a high level step, periods of the mixing and rinsing process S600, the mixing process S700, the rinsing process S800 and the resting process S900 are set to be 3 minutes, 10 minutes, 40 seconds and 60 minutes, respectively, and the temperature of the hot water is set to be 6O⁰C. The low, middle and high level steps are selectively used according to the amount and quality of food waste.

[40] An apparatus for resolving food waste using aerobic microorganisms comprises a mixing basin 10, a plurality of nozzles 54, a mixing shaft 13, a mixing blade 30, a discharge guide 40, a heater 50, a hot water jacket 51, a first rinsing nozzle 41, a second rinsing nozzle 42, a humidity adjustment and deodorization means 600, a heat- keeping member 7, and a frame 70.

[41] [First Embodiment]

[42] The mixing basin 10 is a box shape with an open upper end and a closed lower end which is semi-cylindrical. The lower end portion of the mixing basin 10 has a perforated portion 12, and bearings 11 are installed on both sides of the lower end portion thereof.

[43] The plurality of nozzles 54 is provided to a first water pipe 52 which extends in the longitudinal direction of the mixing basin 10 and is installed at the upper portion of the mixing basin 10. The nozzles 54 are arranged at regular intervals, having certain angles between them such that hot water can be sprayed therethrough in many directions.

[44] The mixing shaft 13 has a first end combined with the bearing 11 installed at one side of the mixing basin 10, and a second end passing through the other bearing 11 and connected to an attenuation gear 21 and a driving motor 20.

[45] The mixing blade 30 is installed in a manner such that a plurality of bars 13 extends from the mixing shaft 13 in a direction perpendicular to the mixing shaft 13, and the mixing blade 30 is coupled to the bars 13. The mixing blade 30 plays a role in mixing and pulverizing wood chips 2 and food waste 3.

[46] The mixing blade 30 comprises the plurality of bars 31 extending from the mixing shaft 13 in a direction perpendicular to the mixing shaft 13, a first mixing blade 32 extending from the center portion of the bar 31 and having a helical shape with respect to the mixing shaft 13 and rotating together with the mixing shaft 13 for shifting the mixture of the wood chips 2 and the food waste 3 in a first direction, a second mixing blade extending from an end portion of the bar 31 in a helical shape with respect to the mixing shaft 13 and rotating together with the mixing shaft 13 for shifting the mixture in a second direction, which is opposite the first direction, and a first pulverizing blade 34 extending along the bar 31 from a location at which the first mixing blade 32 is disposed to near the mixing shaft 13 for pulverizing the mixture while rotating together with the mixing shaft 13. The first mixing blade 32 and the second mixing blade 33 are symmetrically arranged on the left side and the right side, respectively, of the center portion of the mixing shaft 13. The first mixing blade 32 may have a pushing area for pushing the mixture of the wood chips 2 and the food waste 3, which is larger than that of the second mixing blade because the first mixing blade 32 is smaller than the second mixing blade in order to balance the amount of shifted mixture.

[47] Thanks to this structure of the mixing blades 30, the food waste 3 is mixed and pulverized, and the food 3 waste is pushed due to the angle of the mixing blades 30 if the food waste becomes stuck between the mixing blades 30 and the wall of the mixing basin 30, so that events that cause the stoppage of the apparatus do not occur.

[48] The rotation directions of the mixing blades 30 are determined in a manner such that the rotation of the first mixing blade 32 makes the mixture move toward the center of the mixing basin 10, and the rotation of the second mixing blade 33 prevents the mixture of the wood chips and the food waste from gathering near the bearings 11 and from becoming stuck in the bearings 11 provided at respective end portions of the mixing shaft 13, and thus prevents the bearings 11 from rusting due to salt contained in the food waste.

[49] The discharge guide 40 is disposed under the perforated portion 12 of the mixing basin 10 so as to surround the perforated portion 12, and is inclined.

[50] The heater 50 has a predetermined length and width, and is wound around the outer surface of the lower part of the mixing basin, and particularly, around the semi- cylindrical portion of the mixing basin at locations where it is not surrounded by the discharge guide 40. The heater 50 keeps the mixing basin 10 warm at a temperature in the range from 35 to 55⁰C.

[51] The hot water jacket 51 is made of synthetic resin or glass material so that it can endure hot temperatures. The hot water jacket 51 is disposed to be in contact with the outer surface of one side of the mixing basin 10, and has a bar-type heater 56 inside it, thereby heating water supplied through the water supply pipe 55 to a temperature of 30 to 6O⁰C and minimizing heat loss because it is installed near the heater 50. As a result, hot water 6 can be supplied to a first water pipe 52 and a second water pipe 53. The hot water jacket 51 can also be designed to surround the side of the discharge guide 40 in order to heat the discharge guide 40, so that aqueous solution, containing inorganic matter discharged through the perforated portion 12 and fat matter, can be effectively discharged, without being solidified.

[52] The rinsing nozzle comprising the first rising nozzle 41 and the second rinsing nozzle 42, is installed in a manner such that the first rinsing nozzle 41 is installed at the highest portion of the discharge guide 40, which is at an incline, and sprays the hot water 6 toward lower portions of the discharge guide 40 after receiving the hot water 6 from the second water pipe 53, thereby helping the aqueous solution, which contains inorganic matter and falls from the discharge guide 40 through the perforated portion 12 of the mixing basin 10, be discharged, and the second rinsing nozzle 42 sprays the hot water 6 from the same location as the first rinsing nozzle 41 toward the entire perforated portion 12, thereby rinsing the aqueous solution containing inorganic matter attached to the surface of the perforated portion 12.

[53] The oxygen supply and humid air discharge means 60 comprises a blower or a fan

61 for forcedly introducing air into the mixing basin 10 through an air input hole 62 provided in the upper end portion of the first side of the mixing basin 10 in order to supply a sufficient amount of oxygen into the mixing basin 10, and an overflow discharge hole 63 formed in the upper end portion of the second side of the mixing basin 10 to allow humid air to be discharged therethrough by being pushed by the introduced dry air. Since oxygen is continuously and stably supplied into the mixing basin 10 by the blower or the fan 61 through the air input hole 62, formed in an upper portion of a first side of the mixing basin, along with dry air, and the humid air in the mixing basin 10 is pushed by the introduced dry air and forcedly discharged through the overflow discharge hole 62 in the second side of the mixing basin 10 because the mixing basin 10 is sealed by the cover 71 and the rubber packing 711, the odors of the food waste are not emitted into the space in which the apparatus is installed, and the humidity of the mixing basin 10 is maintained at 50 to 60%RH.

[54] The heat-keeping member 7 is installed to surround the mixing basin 10, the heater

50, the hot water jacket 51 and the discharge guide 40, thereby maintaining the internal temperature of the mixing basin 10.

[55] A controller 80 is installed at the side of the mixing basin 10, and controls the entire apparatus using a manipulator 81 connected to the driving motor 20, the nozzle 54, the first and second rinsing nozzles 41 and 42, the heater 50 and the fan 62.

[56] The frame 70 surrounds the above-described elements so that the elements are disposed inside it, and has a cover 71 which can be opened and closed at an upper and front portion thereof, and a wheel 72 at a lower side thereof.

[57] The cover 71 is preferably installed in a manner such that power supplied to the apparatus 1 is interrupted if the cover 71 is opened while the food waste resolution treatment apparatus 1 is operating, resulting in the prevention of a safety hazard and related accidents. A power interruption means is a conventionally known technology, and thus a detailed description thereof will be omitted.

[58] The cover 71 is also provided with a rubber packing 711 attached to the surface thereof, so that odors of the food waste do not permeate outside through gaps between the cover and the frame. Accordingly, the environment in which the apparatus 1 is installed is not degraded.

[59] [Second Embodiment]

[60] Most of the elements in the apparatus according to the second embodiment and the apparatus according to the first embodiment of the present invention are the same, except for the structure of the mixing blade 30 and the mixing shaft 13.

[61] The mixing blade of the apparatus according to the second embodiment comprises a plurality of bars 35 extending from the mixing shaft 13 in a direction perpendicular to the mixing shaft 13, in which adjacent bars 35 have a certain angle between them, a plurality of first mixing bars 37, each extending from the end portion of the bar 35 in the same direction as the mixing shaft 13 and having hooks 36 provided at respective ends thereof, the first mixing bars 37 serving to stir the mixture of wood chips and food waste while rotating together with the mixing shaft 13, a plurality of pulverizing rings 38 wound around the first mixing bars 37 in a manner such that the rings 38 are not separated from the first mixing bars 37, thanks to the hooks 36, but move back and forth, and a plurality of second mixing bars 39, each extending from the mixing shaft 13 in a direction perpendicular to the mixing shaft 13 and opposite the extending direction of the first mixing bars 37, and having an end with the arc shape.

[62] The mixing shaft 13 is eccentric to one side of the mixing basin 10, so that the end of each of the first mixing bars 37 is nearly in contact with the internal surface of the wall of the mixing basin 10, with a distance between them when the first mixing bars 37 rotate, and the distance may be in the range from 1 to 3 millimeters.

[63] In the apparatus having the above-described structure, the first mixing bars 37 and the second mixing bars 39 rotate one after the other in order to stir and pulverize the mixture, and the plurality of pulverizing rings 38 serves to pulverize and soften food waste by being nearly in contact with the internal surface of the wall of the mixing basin 10, with a predetermined distance between them. The pulverizing rings 38 can slightly move back and forth and the motion thereof is stopped by the hook 36. Ends of the second mixing bars 39, which have the arc shape, serves to chop the food waste, so that the food waste can be mixed and pulverized uniform.

[64] [First Experiment]

[65] The cover 71, which can be opened and closed and is provided at the front upper portion of the frame 70 of the food waste resolution treatment apparatus 1 having a mixing basin 10 with an internal capacity of 10OL, was opened, 62kg of wood chips 2, having grain sizes of 5 to 7 millimeters, were input into the mixing basin 10 surrounded by the heater 50 and heated to 5O⁰C to occupy 40% of the total volume of the mixing basin 10, lOOcc of aerobic microorganisms in liquid form were input into the mixing basin 10, and then the cover 71 was closed (SlOO).

[66] Next, the mixing and spraying process S600, the mixing process S700, the rinsing process S800 and the resting period S900, described above, were conducted one after another for 1 minute 30 seconds, 15 minutes, 40 seconds, and 60 minutes, respectively. At this time, the temperature of the hot water sprayed into the mixing basin 10 was 6O⁰C. That is, the middle level step was performed.

[67] Next, while hot water 6, heated to 6O⁰C by the bar-type heater 56, was periodically sprayed using the plurality of nozzles 54 provided to the first water pipe 52 installed at the upper portion of the mixing basin 10, the mixing and pulverizing process performed by the mixing blade 30 and the resting processes were repeated for 10 hours, so that the microorganisms were cultured (S200).

[68] After finishing the culture of the microorganisms, the cover 71 of the mixing basin

10 was opened, and food waste (100kg) 3 was input into the mixing basin so that the food waste occupied 40volume% of the total volume of the mixing basin 10 (S300).

[69] Next, while the hot water 6 heated by the bar-type heater 56 in the hot water jacket

51 to 6O⁰C was periodically sprayed using the nozzles 54 in order to rinse and remove mucous matter generated when the microorganisms digest and decompose food waste, the mixing and pulverizing process performed by the mixing blade 30 installed in the center of the mixing basin 10 and the resting process were repeatedly performed for 12 hours. As a result, 99% of food waste (organic matter, such as starch, fibroid material, fat and protein) was turned into inorganic matter, and 1% of food waste (lime) was discharged through the perforated portion 12 and via the discharge guide 40, along with the inorganic matter dissolved in water (S400).

[70] The above-described food waste decomposition process S400 turned most of the food waste 300 into inorganic matter after 4 hours had passed from the beginning of the process S400 and thus most of the food waste 300 was removed. Accordingly, 5 hours after the beginning of the decomposition process S500 and the food waste input process S300 could be performed again.

[71] According to the experiment, all of the food waste 3 had been treated 12 hours after the food waste was input, and only the wood chips 2 and aerobic microorganisms remained in the mixing basin.

[72] While the entire process was performed, using the oxygen supply and humid air discharge means 60, external dry air was forcedly input into the mixing basin 10 by the blower or the fan 61 through the air input hole 62 formed in the upper portion of a first side of the mixing basin 10, and internal humid air in the mixing basin 10 is pushed away by the flow of the dry air, and discharged through the overflow discharge hole 63 formed in the upper portion of a second side of the mixing basin 10. Since external dry air is introduced into the mixing basin 10 and thus oxygen, needed for the cultivation of microorganisms, is continuously and stably supplied to the microorganisms, the humid air having offensive odors is discharged through the overflow discharge hole 63 into a drain, and the apparatus is sealed by the cover 71 and the rubber packing 711, a clean and pleasant environment for the use of the above-described food waste resolution treatment apparatus (S500) is provided.

[73] The food waste resolution treatment apparatus 1 according to the present invention can adjust the internal temperature of the mixing basin 10 and the temperature of hot water 6 sprayed into the mixing basin 10 using the nozzles 54 over a plurality of steps according to conditions and influx so that the mixing basin 10 has optimum conditions under which aerobic microorganisms can actively digest and decompose organic waste. Further, the food waste resolution treatment apparatus 1 according to the present invention can adjust the humidity in the mixing basin 10 using the humidity adjustment and deodorization means 60. Accordingly, the apparatus 1 can provide an optimum environment for microorganisms regardless of the season.

[74] The present invention has been explained above with reference to an embodiment thereof, but the present invention is not limited to the above-described embodiment. In concluding the detailed description, those skilled in the art will appreciate that many variations and modifications can be made to the preferred embodiment without departing from the principles of the present invention. Therefore, it will be readily understood that such variations and modifications to the preferred embodiment are within the scope of the present invention as defined in the claims.

Claims

[1] A method of resolving food waste (organic matter) into inorganic matter using aerobic microorganisms, comprising: a microorganism input process SlOO for inputting wood chips having grain size of 4 to 8 millimeters into a mixing basin, heated to a temperature in the range from 25 to 55⁰C and surrounded by a heater to occupy 35 to 45 % of the total volume of the mixing basin, and inputting microorganisms in liquid form into the mixing basin by an amount in proportion to a capacity of the mixing basin; a microorganism culture process S200 for culturing microorganisms, in which a mixing and pulverizing period, in which mixing and pulverizing are performed by a mixing blade installed at a center portion of the mixing basin, and a resting period are repeated for 8 to 12 hours while hot water having a temperature in the range from 30 to 6O⁰C is periodically sprayed using nozzles from an upper portion of the mixing basin; a food waste input process S300 for inputting food waste into the mixing basin through an opening after opening a cover until the food waste occupies 45% of the total volume of the mixing basin; a food waste decomposition process S400 for mineralizing the food waste into inorganic matter, in which mixing and pulverizing periods, in which mixing and pulverizing are performed by the mixing blade installed at the center portion of the mixing basin, and resting periods are repeated for 10 to 14 hours while hot water at a temperature in the range from 30 to 6O⁰C is periodically sprayed using the nozzles from an upper portion of the mixing basin; and an oxygen supply and humid air discharge process S500 performed simultaneously with all of the above processes for supplying a sufficient amount of oxygen into the mixing basin and purging humid air in the mixing basin, by forcedly introducing external dry air into the mixing basin using a blower or a fan through an air input hole formed in an upper portion of a first side of the mixing basin, so that the humid air in the mixing basin is pushed and exhausted out through an overflow discharge hole formed in an upper portion of a second side of the mixing basin, wherein the food waste input process S300 and the food waste decomposition process S400 are conducted again until 5 hours have passed from beginning of the food waste decomposition process S400.

[2] The method according to claim 1, wherein the microorganism culture process

S200 and the food waste decomposition process S400 comprise: a spraying and mixing process S600 for mixing and pulverizing the food waste using the mixing blade while spraying hot water using the nozzles; a mixing process S700 for mixing and pulverizing the food waste using the mixing blade without spraying hot water; a rinsing process S800 for rinsing the food waste and a perforated portion disposed at a lower part of the mixing basin by discharging liquid containing inorganic matter falling to a bottom of the mixing basin via a discharge guide, and by simultaneously rinsing the perforated portion of the mixing basin using a first rinsing nozzle and a second rinsing nozzle; and a resting process S900 for allowing the microorganisms to culture and to actively conduct decomposition, in which the mixing and the rinsing are stopped.

[3] The method according to claim 2, wherein the method is driven by a low level step, a middle level step, and a high level step, in which, periods of the mixing and spraying process S600, the mixing process S700, the rinsing process S 800, and the resting process S900 are set to be 1 minute, 10 minutes, 30 seconds and 60 minutes, respectively, and temperature of the hot water is set to be 6O⁰C in the low level step, periods of the mixing and spraying process S600, the mixing process S700, the rinsing process S 800, and the resting process S900 are set to be 1 minute 30 seconds, 15 minutes, 40 seconds and 60 minutes, and temperature of the hot water is set to be 6O⁰C in the middle level step, and periods of the mixing and spraying process S600, the mixing process S700, the rinsing process S800, and the resting process S900 are set to be 3 minutes, 10 minutes, 40 seconds and 60 minutes, and temperature of the hot water is set to be 6O⁰C in the high level step.

[4] An apparatus for resolving food waste (organic matter) into inorganic matter using aerobic microorganisms, comprising: a mixing basin having a perforated portion at a lower part thereof; a plurality of nozzles coupled to a first water pipe installed to extend in a longitudinal direction at an upper portion of the mixing basin, the nozzles having certain angles and intervals therebetween, for spraying water in a plurality of directions; a mixing shaft having a first end and a second end combined with bearings installed in the mixing basin, either the first end or the second end penetrating the bearing and being connected to an attenuation gear and a driving motor; a mixing blade including a plurality of bars extending from the mixing shaft in a direction perpendicular to the mixing shaft and a plurality of blades provided to end portions of the bars for mixing and pulverizing wood chips and food waste; a discharge guide, installed to surround the perforated portion of the mixing basin, and inclined relative to a vertical direction; a heater surrounding a semi-cylindrical lower part of the mixing basin and having a predetermined length and width; a heat-keeping member surrounding the mixing basin, the heater and the discharge guide for maintaining internal temperature of the mixing basin; a controller installed at a side of the mixing basin and having a manipulator connected to the driving motor, the nozzles, the heater, and the fan for controlling overall operation of the apparatus using the manipulator; and a frame enclosing all of the above-described elements therein and having a cover at an upper portion thereof and a wheel at a lower side thereof; and further comprising: a hot water jacket disposed to be in contact with one side of the mixing basin, bring water supplied through a water supply pipe into contact with the heater, and having a bar-type heater therein, for supplying hot water to a first water pipe and a second water pipe; a first rinsing nozzle and a second rinsing nozzle, the first rinsing nozzle disposed at the highest portion of the discharge guide, which is inclined, for receiving the hot water via the second water pipe and spraying the hot water to locations having low slopes, the second rinsing nozzle disposed at the same position as the first rinsing nozzle and spraying the hot water toward the entire surface of the perforated portion; an oxygen supply and humid air discharge unit including a blower or a fan for blowing external dry air into the mixing basin through an air input hole formed in an upper portion of a first side of the mixing basin in order to sufficiently supply oxygen into the mixing basin, and an overflow discharge hole formed in an upper portion of a second side of the mixing basin for allowing humid air in the mixing basin to be discharged therethrough by being pushed by the introduced external dry air.

[5] The apparatus according to claim 4, wherein the mixing blade comprises: a plurality of bars extending from the mixing shaft in a direction perpendicular to the mixing shaft; a plurality of first mixing blades, each helically extending from a center portion of each of the bars in one direction with respect to the mixing shaft for shifting a mixture of the wood chips and the food waste in a first direction while rotating together with the mixing shaft; and a plurality of second mixing blades, each helically extending from an end portion of each of the bars in a direction opposite the direction of the first mixing blade for shifting the mixture of the wood chips and the food waste in a second direction, which is opposite the first direction, by rotating together with the mixing shaft; and a plurality of first pulverizing blades, each extending along each of the bars from the first mixing blade to have a predetermined width for pulverizing the mixture by rotating along with the mixing shaft; wherein the first mixing blade and the second mixing blade are symmetrically arranged with respect to a middle portion of the mixing shaft, and the first mixing blade has a pushing area larger than the second mixing blade, having a relatively large size, in comparison with the second mixing blade in order to balance an amount of shifted mixture of the food waste and the wood chips.

[6] The apparatus according to claim 5, wherein a rotation direction of the mixing blade is determined in a manner such that the mixture is moved toward the center of the mixing basin by rotation of the first mixing blade.

[7] The apparatus according to claim 4, wherein the mixing blade comprises: a plurality of bars, each extending from the mixing shaft in a direction perpendicular to the mixing shaft, and adjacent bars having an angle between them; a plurality of first mixing bars, each extending from an end of each of the bars, having a predetermined length in a direction in which the mixing shaft extends, and each being provided with a hook at an end thereof, for mixing the mixture of the wood chips and the food waste by being rotated by the mixing shaft; a plurality of pulverizing rings surrounding each of the first mixing bars and moving back and forth but not coming separated from the first mixing bars due to the hook; and a plurality of second mixing bars, each extending from the mixing shaft in a direction perpendicular to the mixing shaft but opposite a direction of the first mixing bars, and having an end with an arc shape.

[8] The apparatus according to claim 7, wherein the mixing shaft is eccentric to a side of the mixing basin in longitudinal direction thereof, and thus an end of the first mixing bar is nearly in contact with a surface of a wall of the mixing basin, with a predetermined distance when the first mixing bar is rotated, and the distance may be in the range from 1 to 3 millimeters.