Patent Publication Number: US-2013247628-A1

Title: Apparatus and method for treating organic waste

Description:
TECHNICAL FIELD 
     Embodiments of the present invention relate to an apparatus and method for treating organic waste. More specifically, embodiments of the present invention relate to an apparatus and method for treating organic waste to treat inorganic waste and thereby produce organic compost and high-concentration liquid fertilizer. 
     BACKGROUND ART 
     Organic waste such as manure, human feces and food waste has a high water content and discharges high-concentration contaminant, thus causing serious environmental pollution, such as water pollution and bad smell, when discharged or disposed of without any treatment. 
     Recently, a great deal of research has focused on environmentally friendly methods of treating organic waste and utilizing the same as a resource. A method for composting an organic substance using aerotropic or anaerobic microorganisms is known. Treatment using aerotropic microorganisms is a composting method in which an organic substance is decomposed by oxidation with aerotropic microorganisms and the residue is stabilized. Treatment using anaerobic microorganisms is a method for composting an organic substance through decomposition using anaerobic bacterium, which yields methane gas as a by-product. 
     However, these methods have disadvantages of a complicated treatment process, and the necessity of a large treatment area and of a long treatment period of one to two months. Further, these methods have disadvantages of production of waste water or bad smell due to the difficulty of complete treatment. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     It is an aspect of the present invention to provide an apparatus and method for treating organic waste to reduce treatment costs and period, enable environmentally friendly treatment without causing bad smell or waste water, and thereby prepare an organic compost with a high quality and a high concentration liquid fertilizer. 
     Solution to Problem 
     According to a technical concept of the present invention, there is provided an apparatus for treating organic waste, including: a sealable reaction vessel including an inlet through which an organic waste and a reactive additive are injected, an outlet through which a treated substance is discharged as reactive gas; a stirrer to stir contents of the reaction vessel; and a liquid fertilizer producer to condense the reactive gas discharged from the gas outlet with a cooling solution and thereby produce a liquid fertilizer, while gradually increasing the concentration of fertilizer components of the cooling solution. 
     The liquid fertilizer producer may include: a cyclone condensation vessel to induce circling and ascending of the reactive gas, the cyclone condensation vessel provided at a lower side thereof with an inlet for the reactive gas and at an upper side thereof with an outlet for the remaining gas; a liquid vessel to accept a liquid flowing downward from the condensation vessel and containing a cooling solution filled therein; and a cooling solution spray to elevate a cooling solution of the liquid vessel and thus spray the cooling solution to an upper region inside the condensation vessel. 
     The condensation vessel may include a plurality of partition boards to divide the condensation vessel into multiple stages of upper and lower parts and thereby form a curved passage, and a plurality of carriers filled in an upper area of the partition boards to facilitate contact of the cooling solution sprayed from the top with the ascending reactive gas. 
     The apparatus may further include: an electric open/close valve mounted in a pipe to connect the gas outlet to the condensation vessel, to open the gas outlet, when an inner pressure of the reaction vessel reaches a predetermined reaction pressure or higher, and to close the gas outlet, when an inner pressure of the reaction vessel is less than the predetermined reaction pressure. 
     The apparatus may further include: a safety valve provided in the reaction vessel, to discharge the reactive gas to the outside, when the inner pressure of the reaction vessel is a predetermined safety pressure or higher. 
     The stirrer may further include: a rotation axis transversely passing through the inner center of the reaction vessel and having both ends rotatably supported at the center of caps; a mixing blade mounted on the rotation axis; and a driving motor mounted at the outer side of the reaction vessel to rotate the rotation axis. 
     The mixing blade may include: a first mixing blade which spirally extends around the rotation axis such that the first mixing blade is close to the inner surface of the reaction vessel and is supported by a plurality of support members radially extending from the rotation axis; and a plurality of second mixing blades extending from the rotation axis in a radial direction to a length shorter than the radius of the first mixing blade and having a torsion angle to stir contents, while transporting the contents in a direction opposite to the first mixing blade. 
     The reaction vessel may include: a cylindrical body; and a pair of caps connected to the ends of the body, respectively, and wherein an outlet is provided under one cap, to discharge waste treated in the reaction vessel by rotation of the first mixing blade. 
     The apparatus may further include a pre-heater to preheat the reaction vessel, wherein the pre-heater includes: a water jacket mounted on the outer surface of the reaction vessel; and a warm water boiler to circulate warm water to the water jacket. 
     The apparatus may further include: a base frame to support the reaction vessel, the liquid fertilizer producer and the pre-heater arranged thereunder; a vessel frame mounted on the base frame, to support the reaction vessel; and a plurality of weight sensors mounted between the vessel frame and the base frame, to sense the weight of the contents contained in the reaction vessel. 
     According to a technical concept of the present invention, there is provided a method for treating organic waste including: a preparation process in which organic waste having a water content of about 75 to 85% is supplied to the reaction vessel and pre-heated to 50 to 60° C. by heating under stirring; an additive supply process, in which a reactive additive containing 20 to 30% by weight of quicklime, with respect to the total weight of contents, is added to the preheated reaction vessel; after addition of the reactive additive, a reaction process, in which the reaction vessel is sealed and the contents are stirred, to induce reaction of organic waste with the reactive additive, cause heat generation and decomposition of organic substances and thereby produce an organic fertilizer, wherein the gas outlet of the reaction vessel opens and closes, thereby maintaining the inner pressure of the reaction vessel at about 2 to 2.5 kg/cm 2  to facilitate the reaction; and a liquid fertilizer preparation process in which the reactive gas discharged to the gas outlet is supplied to the condensation vessel, in which a cooling solution is sprayed, in the reaction process, to allow the reactive gas to be condensed by the cooling solution and thereby produce a liquid fertilizer. 
     The total volume of contents including organic waste and reactive additive may be adjusted to ⅔ or less of the inner volume of the reaction vessel to secure an extra area for reaction activation. 
     The reaction process may be carried out at an inner temperature of the reaction vessel of 90 to 100° C. for 10 to 15 minutes. 
     Advantageous Effects of Invention 
     The present invention provides an apparatus for treating organic waste in which organic waste and a reactive additive are added to a reaction vessel and reacted with each other to treat organic waste, thus minimizing treatment costs and period of organic waste and enabling environmentally friendly treatment without causing bad smell or waste water, thereby preparing an organic compost with a high quality and a high concentration liquid fertilizer. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       These and/or other aspects of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  illustrates the configuration of an apparatus for treating organic waste according to the present invention; 
         FIG. 2  is a sectional view illustrating the inner configuration of a reaction vessel of the apparatus for treating organic waste according to the present invention; 
         FIG. 3  is a sectional view taken along the line of III-III′ of  FIG. 2 ; 
         FIG. 4  is a sectional view illustrating the configuration of a liquid fertilizer producer of the apparatus for treating organic waste according to the present invention; and 
         FIG. 5  shows reaction schemes illustrating a series of chemical changes of various substances occurring in the reaction vessel. 
     
    
    
     MODE FOR THE INVENTION 
     Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     The apparatus for treating organic waste according to the present invention as shown in  FIGS. 1 and 2 , includes a reaction vessel  10 , a stirrer  20  to stir the material contained in the reaction vessel  10 , a pre-heater  30  to pre-heat the reaction vessel  10  and a liquid fertilizer producer  60  to condense a reaction gas and thus prepare a liquid fertilizer. Further, this apparatus also includes a base frame  40  to mount the reaction vessel  10 , the liquid fertilizer producer  60 , the pre-heater  30  and the like thereon and support the same, the base frame  40  mounted on a plurality of movable casters  41 , a vessel frame  43  mounted on the base frame  40 , to support the reaction vessel  10 , and a movable supply hopper  50  to facilitate supply of contents to the reaction vessel  10 . 
     The reaction vessel  10 , as shown in  FIG. 2 , includes a cylindrical body  11  with opened both ends, and hemispherical caps  12  and  13  connected to both ends of the body  11 , respectively, to close the both ends. An inlet  14  is arranged above the body  11  to supply organic waste and a reactive additive, and the inlet  14  is provided with an inlet cover  14   a  to seal the inlet  14 . In addition, an outlet  15  is arranged under the cap  12 , to discharge waste (organic compost) treated in the reaction vessel  10  and the outlet  15  is also provided with an outlet cover  15   a  to seal the outlet  15 . The organic waste treated in the reaction vessel  10  may be manure, human feces, food waste, or the like. The reactive additive reacted with the organic waste may be quicklime, germanium, moisture additive or the like. This will be described in the illustration of the following operation and treatment method in more detail. 
     A gas outlet  16  to discharge the reactive gas generated in the reaction vessel  11  is provided on the body  11  of the reaction vessel  10  and a pipe  46  to guide the reactive gas to the liquid fertilizer producer  60  is connected to the gas outlet  16 . In addition, the reaction vessel  10  is provided with a pressure gauge  17  to sense an inner pressure, a temperature gauge  18  to sense an inner temperature, and a safety valve  19  to automatically discharge a gas, when the inner pressure of the reaction vessel  10  increases to a predetermined safety pressure (3 kg/cm 2 ) or higher. 
     The stirrer  20  includes, as shown in  FIGS. 1 and 2 , a rotation axis  21  transversely passing through the inner center of the reaction vessel  10  and having both ends rotatably supported at the center of caps  12  and  13 , a first mixing blade  22  and a plurality of second mixing blades  23  mounted on the rotation axis  21  and a driving motor  24  mounted at the outer side of the reaction vessel  10  to rotate in a direct or reverse direction. The driving motor  24  and the rotation axis  21  are connected to each other through a belt  26  and a pully  27  to transfer power. 
     The first mixing blade  22  has a predetermined width and spirally extends around the rotation axis  21  such that it is close to the inner surface of the reaction vessel  10 . In addition, the first mixing blade  22  is supported by a plurality of support members  22   a  radially extending from the rotation axis  21 . In addition, the plurality of second mixing blades  23  extend from the rotation axis  21  in a radius direction to a length shorter than the radius of the first mixing blade  22 , and have a torsion angle to stir contents, while transporting the contents in a direction opposite to the first mixing blade  22 . 
     As shown in  FIG. 2 , the torsion angle enables the contents arranged at the center of the reaction vessel  10  to be moved in the opposite direction through the second mixing blades  23 , when the contents arranged at the inner surface of the reaction vessel  10  are moved in one direction to the first mixing blade  22 . When the rotation direction of the rotation axis  21  is changed, movement direction of the contents through the mixing blades  22  and  23  is also changed. In addition, when the waste treated in the apparatus is discharged, the first mixing blade  22  close to the inner surface of the reaction vessel  10  transports the inner waste of the reaction vessel  10  to the outlet  15 , to facilitate the transportation. 
     As shown in  FIGS. 1 and 3 , the pre-heater  30  includes a water jacket  31  mounted at a lower side and a peripheral outer surface of the reaction vessel  10  and a warm water boiler  32  to circulate warm water to the water jacket  31 . As shown in  FIG. 1 , the warm water boiler  32  is mounted on the base frame  40  at the side of the reaction vessel  10 , and the warm water boiler  32  is connected to the water jacket  31  through pipes  33  and  34 . This enables warm water heated by the warm water boiler  32  to be supplied to the water jacket  31  and thus circulated, thereby heating the reaction vessel  10 . Although an example in which the warm water boiler and the water jacket are used as the pre-heater  30  is illustrated, a general electric heater may be utilized. 
     As shown in  FIG. 1 , a plurality of weight sensors  44  to sense the weight of the contents contained in the reaction vessel  10  are mounted between the vessel frame  43  to support the reaction vessel  10  and the base frame  40 . The information detected by the weight sensor  44  is displayed through a display member of a control panel (not shown) to enable a user to confirm the information and thereby contribute to prevention of excessive supply of the contents. As shown in  FIG. 4 , the liquid fertilizer producer  60  to condense the discharged reactive gas and thus produce a liquid fertilizer includes a cylindrical cyclone condensation vessel  61 , a liquid vessel  62  filled with a cooling solution, arranged under a condensation vessel  61  such that it supports the bottom of the condensation vessel  61 , and a cooling solution spray  70  to elevate the cooling solution of the liquid vessel  62  and to spray the same to an upper area provided inside the condensation vessel  61 . 
     The cyclone condensation vessel  61  has an opened bottom and is provided at a lower side thereof with an inlet  61   a  for the reactive gas and at an upper side thereof with an outlet  61   b  for the remaining gas. Further, to induce detour of the injected reactive gas, the condensation vessel  61  is provided at an eccentric position thereof with the inlet  61   a.    
     As shown in  FIG. 1 , the inlet  61   a  of the condensation vessel  61  is connected to a pipe  46  which extends from the gas outlet  16  of the reaction vessel  10 , to enable the reactive gas to be supplied from the reaction vessel. This pipe  46  is connected in a bent form, in order to reduce vibration and shock caused by discharge pressure of the reactive gas. 
     A part (top) in which the liquid vessel  62  is connected to the bottom of the condensation vessel  61  communicates with the condensation vessel  61  in order to allow injection of a liquid which flows downward from the condensation vessel  61 . The liquid vessel  62  may be provided with a pipe  63  to supply a cooling solution and a pipe  64  to discharge a diluted liquid fertilizer produced by condensation of the reactive gas. 
     A cooling solution spray  70  includes a pump  71  to intake and deliver a cooling solution, an intake pipe  72  mounted in the liquid vessel  62  and connected to an inlet of the pump  71 , a discharge pipe  73  connected to an outlet of the pump  71  and having a top present in the condensation vessel  61 , and a spray nozzle  74  mounted on the end of the discharge pipe  73  in the condensation vessel  61 . 
     The condensation vessel  61  includes a first partition board  65  and a second partition board  66  to divide the condensation vessel  61  into multiple stages of the upper and lower parts and thereby form a curved passage, and a plurality of carriers  67  filled in a upper region of the second partition board  66  to facilitate contact of the cooling solution sprayed from the top with the ascending reactive gas. 
     The first partition board  65  has a circular circumference spaced from the inner surface of the condensation vessel  61 , and the second partition board  66  is arranged above the first partition board  65  such that it is spaced from the first partition board  65 , has a center with an opening  66   a  and has a ring-shaped circumference connected to the inner surface of the condensation vessel  61 . This enables an ascending passage of the reactive gas supplied to the condensation vessel  61  to be curved and thus lengthened, and improves condensation effect of the reactive gas by cooling water. 
     The carriers  67  may take the shape of a polygon or ball with a plurality of holes and may be provided with a plurality of horns protruding outward. These carriers  67  improve an opportunity to bring ascending reactive gas into gaps provided therebetween in contact with cooling water flowing downward from the top and thus enhance condensation of the reactive gas. 
     An electric open/close valve  47  which opens the gas outlet  16 , when an inner pressure of the reaction vessel  10  reaches a predetermined reaction pressure (2 to 2.5 kg/cm 2 ) or higher, and closes the gas outlet  16 , when an inner pressure of the reaction vessel  10  is less than the predetermined reaction pressure is mounted in a pipe  46  to connect the gas outlet  16  of the reaction vessel  61  to the inlet  61   a  of the condensation vessel  61 . This maintains the inner pressure of the reaction vessel  10  at 2 to kg/cm 2  during the reaction process, and thus promotes reaction and enables the reactive gas to be discharged to the condensation vessel  61 , when the pressure exceeds the predetermined level. A safety valve  19  opens and discharges the reactive gas outside, when the inner pressure of the reaction vessel  10  reaches a safety pressure of about of 3 kg/cm 2  or higher. 
     As shown in  FIG. 1 , the movable supply hopper  50  is connected to an electric hoist  53  which moves along a rail supported by a structure  51  and mounted on the reaction vessel  10 . The hoist  53  enables ascending and movement of the movable supply hopper  50  and easy supply of the reactive additive such as organic waste or quicklime to the reaction vessel  10 . Although the movable supply hopper  50  is suggested as a supply medium, the supply medium is not limited thereto and may be an automatic supply system to carry organic waste or reactive additive from a storage region to the reaction vessel using a transfer pump  71  or conveyor. 
     A method for treating organic waste using this apparatus will be described. 
     The organic waste to be treated may be pig, livestock, chicken or human waste. In order to treat organic waste, first, a preparation process in which organic waste is supplied to the reaction vessel  10  and pre-heated. The supplied organic waste has a water content of about 75 to 85%, so that it can react with reactive additive injected into the reaction vessel  10 . 
     After the organic waste is supplied to the reaction vessel  10 , a stirrer  20  is operated to begin stirring of contents. The stirrer  20  repeats direct and inverse rotations at a set interval (about 1 to 2 minutes) to enable the contents to be homogeneously mixed. At the same time, the reaction vessel  10  is pre-heated to 50 to 60° C. by the pre-heater  30 . The simultaneous operation of stirring and pre-heating enables organic waste in the reaction vessel  10  to be homogeneously heated and the same to reach to a temperature suitable for the reaction. 
     After the preparation process, an additive supply process in which quicklime, a germanium powder and a reactive additive containing a predetermined amount of water-absorbent are added to the reaction vessel  10  is performed. Quicklime is added in an amount of 20 to 30% by weight, with respect to the total weight of contents supplied to the reaction vessel  10 . Further, the total volume of contents including organic waste and reactive additive is adjusted to ⅔ or less of the inner volume of the reaction vessel  10 . This secures an extra area for reaction activation inside the reaction vessel  10 . 
     After the reactive additive is added, a reaction process, in which the inlet  14  is sealed with the inlet cover  14   a  and the contents are stirred with the stirrer  20  to induce reaction, is performed. That is, organic waste and reactive additive are homogeneously mixed with the mixing blades  22  and  23  to perform reaction in the reaction vessel  10 . 
     As a result, in the reaction vessel  10 , quicklime reacts with organic waste to produce heat and the inner temperature of the reaction vessel increases to 90 to 100° C. In some cases, the temperature increases up to 150° C. Further, as a result of the reaction, organic waste is decomposed, water content is decreased to a level less than about 25% and the contents are transformed into a high-quality organic fertilizer. Such a reaction process is carried out for 10 to 15 minutes. 
     In the reaction process, organic waste undergoes variation in chemical composition and crystalline structure in the reaction vessel through sequential chemical reactions and is converted into an environmentally friendly organic fertilizer. That is, toxic substances, such as benzene, contained in waste are separated through cleavage of molecular bond between carbon (C) and hydrogen (H). Further, toxic substances such as dioxin, chloroform, TNT and iron chloride are decomposed through a series of reactions and high-quality organic fertilizer components such as nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S) and chlorine (Cl) are thus produced. Further, in the reaction process, salts and bad smells are removed, parasites and pathogenic bacteria are substantially killed and properties thereof are changed to alkali beneficial for soil neutralization.  FIG. 5  shows reaction schemes illustrating a series of chemical variation of substances occurring in the reaction vessel. 
     Further, in the reaction process, the inner pressure of the reaction vessel  10  increases since the reactive gas containing steam and a particle powder is formed. The open/close valve  47  opens the gas outlet  16  to discharge the reactive gas to the liquid fertilizer producer  60 , when the inner pressure increases to 2 kg/cm 2  or higher. The open/close valve  47  automatically opens and closes the gas outlet  16 , depending on variation in the pressure of the reaction vessel  10  and thereby maintains the inner pressure of the reaction vessel  10  at about 2 to 2.5 kg/cm 2 . Maintaining the inner pressure at 2 to 2.5 kg/cm 2  provides conditions beneficial for reaction to the reaction vessel  10  and promotes reactions. 
     In addition to the reaction processes, a liquid fertilizer preparation process in which the liquid fertilizer producer  60  condenses the reactive gas discharged to the gas outlet  16  and produces a liquid fertilizer is carried out. At this time, the reactive gas containing water and a particle powder is injected into the bottom of the condensation vessel  61 , circulates in the condensation vessel  61 , passes through the area provided between the partition boards  65  and  66  and ascends through the gaps between the carriers  67 . At the same time, the cooling solution accepted in the liquid vessel  62  is sprayed above the condensation vessel  61  through the cooling solution spray  70 . Accordingly, ascending reactive gas comes into contact with the cooling solution which is sprayed and flows downward to condense reactive gas, and the condensed liquid flows together with the cooling solution and is accumulated in the liquid vessel  62 . 
     A condensed high-concentration fertilizer component flows downward and is thus mixed with the cooling solution accepted in the liquid vessel  62  to produce a liquid fertilizer and the concentration thereof increases, as the reaction proceeds. That is, such treatment is repeated to convert the cooling solution into a high-concentration liquid fertilizer. 
     The content, that is, organic compost treated in the reaction vessel  10  can be discharged by operating the stirrer  20 , while opening the outlet  15 . This discharge is carried out by the first mixing blade  22  which pushes the contents toward the outlet  15 . The discharged organic compost may be used as a soil conditioner, without any treatment. 
     Although a few embodiments of the present invention have been shown and described in conjunction with accompanying drawings, it is clearly understood that the foregoing embodiments do not particularly restrict the scope of the present invention. Accordingly, it would be appreciated by those skilled in the art that various substitutions, variations and/or modifications may be made in these embodiments without departing from the principles and spirit of the invention.