KR102648025B1 - Organic waste treatment apparatus with improved biogas production and method for treating organic waste using the same - Google Patents

Abstract

A treatment method and treatment device for organic waste with improved biogas production are provided. According to this, the efficiency of the anaerobic digestion process, which accounts for a significant portion of the total processing time of organic waste, is increased, and in particular, the pH shock generated during the anaerobic digestion process, the increase in carbon dioxide partial pressure, and the remaining oil in the liquid waste supplied to the anaerobic digestion process are increased. It can be widely applied to the treatment of various organic wastes as it can maximize the yield of methane, which is biogas, while increasing the efficiency of anaerobic digestion by preventing a decrease in methane production.

Description

Organic waste treatment apparatus with improved biogas production and method for treating organic waste using the same}

The present invention relates to an organic waste treatment device with improved biogas production and a method of treating organic waste using the same.

Modern society is facing the problem of disposing of large amounts of waste that arises along with advanced industrial development. Among them, organic waste such as food waste, livestock waste, and sewage sludge are currently only treated on land as ocean dumping has been banned since 2012.

Several types of methods have been proposed for the treatment of organic waste, and currently, organic waste is treated by mixing and combining these methods. Among the proposed methods, one of the most widely used methods is anaerobic digestion, which is one of the biological treatment methods. Anaerobic digestion has many advantages over aerobic digestion, and is currently widely used for the treatment of organic waste.

In particular, anaerobic digestion is developing into an eco-friendly resource recycling treatment technique that produces fuel from organic waste in addition to the simple decomposition and treatment function of organic waste. Accordingly, composting and feed facilities, which accounted for most of domestic organic waste recycling facilities, are being used. It is being converted to a biogasification facility using this anaerobic digestion method.

On the other hand, when applying the anaerobic digestion method, the organic waste input into the anaerobic digestion tank 40 necessarily goes through a process to remove the oil present in the organic waste, which is one of the main causes of scum in the anaerobic digestion process. One is that the generated scum causes the problem of lowering methane production by methane bacteria. However, it is difficult to 100% remove oil in organic waste, and excessive processing time and cost are required for 100% removal, so the generation of scum due to oil in the anaerobic digester 40 is unavoidable.

In addition, carbon dioxide generated during the anaerobic digestion process forms bubbles on the surface of the anaerobic digestion liquid, and the formed bubbles are also known to inhibit digestion by methane bacteria.

Furthermore, excessive supply of acid fermentation waste liquid containing organic acids accumulated during single-phase anaerobic digestion or organic acids supplied to the methane fermentation tank during two-phase anaerobic digestion excessively lowers the pH of the anaerobic digestion liquid in the single phase or the digestion liquid in the methane fermentation tank, resulting in methane There is a problem of inhibiting the digestive activity of bacteria.

Accordingly, there is a need to develop technology for efficient operation of the anaerobic digestion tank 40 facility by solving the above-mentioned problems at once.

Republic of Korea Patent Publication No. 10-0838589

The present invention was developed in consideration of the above points, and is designed to maintain the maximum amount of biogas production by removing the inhibitory factors of methane fermentation occurring in the anaerobic digestion process, which takes up a significant portion of the processing time required for processing organic waste. The purpose is to provide a treatment device and method for processing organic waste.

In order to solve the above-mentioned problems, the present invention provides a crushing separator (10) for crushing organic waste and sorting out foreign substances, and a solid-liquid waste for separating the crushed and selected organic waste into solid waste and liquid waste, respectively, through the crushing separator (10). Separator (20), three-phase separator (30) for selectively removing oil in the separated liquid waste, anaerobic digestion of liquid waste from which oil has been selectively removed, and anaerobic digestion tank (40) for producing biogas, anaerobic digestion It includes an aerobic digestion tank (50) for aerobically digesting the waste liquid and a filtration tank (60) for filtering foreign substances remaining in the aerobic digestion waste liquid, and the anaerobic digestion tank (40) includes an enzyme converter for conversion of carbon dioxide generated during anaerobic digestion. A device for processing organic waste provided inside is provided.

According to one embodiment of the present invention, it may further include a dryer 70 for drying the solid waste and a condenser 80 for condensing the vapor generated in the dryer 70.

Additionally, the dryer 70 may be operated using biogas produced in the anaerobic digester 40 as a direct or indirect energy source.

In addition, the three-phase separator 30 separates the liquid waste separated by the solid-liquid separator 20 into at least three specific gravity layers by centrifugal force, and then selectively extracts and removes the specific gravity layer where the oil is located. It may be a three-phase centrifuge.

Additionally, the enzyme converter may include a porous mineral support and carbonic anhydrase immobilized on the porous mineral support.

In addition, the mineral porous support is a porous sintered body in which mineral components including pumice and red clay are sintered, and the specific gravity may be less than 1.0.

In addition, the anaerobic digestion tank 40 may further include a nonionic surfactant release device for removing the oil layer formed on the liquid waste.

Additionally, the nonionic surfactant may have a hydrophile-lipophile balance (HLB) value of 11 to 15.

In addition, the present invention includes a crushing and screening step of crushing organic waste and selecting foreign substances; A solid-liquid separation step of dehydrating the organic waste supplied in the crushing and sorting step and separating it into solid waste and liquid waste; An oil removal step of selectively removing oil by three-phase centrifugation of the liquid waste separated in the solid-liquid separation step; An anaerobic digestion step of anaerobically digesting liquid waste from which oil has been selectively removed and producing biogas; An aerobic digestion step of aerobically digesting anaerobic digestion waste fluid; and a filtration step of filtering out foreign substances in the aerobic digestion waste fluid. The anaerobic digestion step provides a method of treating organic waste in which carbon dioxide produced through anaerobic digestion is converted into bicarbonate ions.

According to one embodiment of the present invention, it may include a drying step of drying the solid waste separated in the solid-liquid separation step and a condensate production step of liquefying the vapor generated in the drying step using the condenser 80.

Additionally, the conversion of carbon dioxide generated in the anaerobic digestion step into bicarbonate ions may be performed through an enzyme converter including a mineral porous support and carbonic anhydrase immobilized on the mineral porous support.

The organic waste treatment device and treatment method according to the present invention increases the efficiency of the anaerobic digestion process, which accounts for a significant portion of the total treatment time of organic waste, and in particular, pH shock, increase in carbon dioxide partial pressure, and anaerobic digestion process occurring during the anaerobic digestion process. It can be widely applied to the treatment of various organic wastes as it can maximize the yield of methane, which is biogas, while increasing anaerobic digestion efficiency by preventing a decrease in methane generation due to oil remaining in the liquid waste supplied.

1 is a process diagram for processing organic waste according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in many different forms and is not limited to the embodiments described herein.

Referring to FIG. 1, the organic waste treatment device according to an embodiment of the present invention includes a crushing separator 10 that crushes organic waste and selects foreign substances, and a crushing and sorting device that crushes and selects the organic waste through the crusher 10. A solid-liquid separator (20) that separates organic waste into solid waste and liquid waste, respectively, a three-phase separator (30) that selectively removes oil in the separated liquid waste, anaerobically digests the liquid waste from which oil has been removed, and biogas It includes an anaerobic digestion tank (40) that produces, an aerobic digestion tank (50) that aerobically digests the anaerobic digestion waste fluid, and a filtration tank (60) that filters foreign substances remaining in the aerobic digestion waste fluid.

In addition, an embodiment of the present invention includes a crushing and screening step of crushing organic waste and selecting foreign substances using the above-described organic waste treatment device; A solid-liquid separation step of dehydrating the organic waste supplied in the crushing and sorting step to separate it into solid waste and liquid waste; An oil removal step of selectively removing oil by three-phase centrifugation of the liquid waste separated in the solid-liquid separation step; Anaerobic digestion step of anaerobically digesting liquid waste from which oil has been removed and producing biogas; An aerobic digestion step of aerobically digesting anaerobic digestion waste fluid; and a filtration step of filtering out foreign substances in aerobic digested waste fluid.

First, the crushing selection stage will be explained.

The crushing and sorting stage is a stage in which organic waste of various sizes is crushed to a certain size or less and foreign substances are sorted out. Organic waste input into the shredding separator 10 may include all wastes mainly composed of organic matter, such as livestock or animal waste, and food waste, and may be food waste as an example. The shredding and sorting step is a process for not only crushing waste to a certain size and transforming it to be advantageous for various subsequent processes, but also separating and sorting various foreign substances contained in organic waste. During the crushing process, vinyl, paper, and Contaminants such as suspended or precipitated metals can be selectively removed. At this time, selection and removal may be performed by known methods such as various screens, and the present invention is not particularly limited thereto. At this time, the various contaminants that have been selectively removed are classified according to their material, and then the organic contaminants can be recycled as solid fuel through a known method such as extrusion. In addition, the remaining selected organic waste is supplied to the solid-liquid separator (20).

The crushing and sorting step can be performed through the crushing separator 10, which not only selects and removes various foreign substances such as vinyl, metal, or plastic contained in the organic waste, but also dries the organic waste and uses it as fertilizer raw material. In order to crush the organic waste into a size suitable for processing, it is preferable to sequentially configure the crusher and sorter for the organic waste. At this time, the present invention is not particularly limited, as known shredders and sorters for the organic waste can be used. For example, a screw type shredder with excellent crushing efficiency is preferable.

Next, the solid-liquid separation step is explained. It is a step to separate the supplied organic waste into solid waste and liquid waste. Organic waste contains liquid waste, and if it is used directly as compost, contamination due to liquid leachate may accelerate, and when processed into fuel, the time and cost of drying is excessive, which is undesirable. Accordingly, it goes through a stage of separation into solid waste and liquid waste, and this stage is the solid-liquid separation stage.

The solid-liquid separation step can be performed using a known solid-liquid separator 20 or a dehydration device. For example, it may be a centrifugal separation device that removes liquid waste using centrifugal force.

Next, the oil removal step for the separated liquid waste will be described.

Separated liquid waste contains oil in addition to organic matter to be processed in the subsequent biological digestion, that is, the anaerobic digestion step and the aerobic digestion step. The oil accelerates the formation of scum in the subsequent anaerobic digestion step, lowering the anaerobic digestion efficiency, and bio There is a problem of reducing gas production. Accordingly, an oil removal step is performed to selectively remove oil in the separated liquid waste.

The oil removal step can be performed using a known device for removing oil in organic waste, so the present invention is not particularly limited thereto. For example, it is performed through a three-phase separator 30, and the three-phase separator 30 is used to remove oil. The separator 30 may be a three-phase centrifuge that extracts the liquid waste by the difference in specific gravity caused by centrifugal force. At this time, the oil separated by the three-phase separator 30 can be recycled into soap, biodiesel, power plant fuel, etc. by filtering out harmful components.

Next, the liquid waste from which the oil has been removed is anaerobically digested and an anaerobic digestion step is performed to produce biogas.

The anaerobic digestion step is a series of processes that convert organic matter into methane through the decomposition action of various microorganisms. Specifically, a hydrolysis process that liquefies and hydrolyzes organic matter, and produces organic acids such as vinegaric acid, propionic acid, and butyric acid. It includes an organic acid production process and a methane production process that generates methane biogas through the generated organic acid, and the microorganisms and optimal reaction conditions involved in each of these processes may be different. Accordingly, the anaerobic digestion step is performed using a single-phase equipment configured so that the hydrolysis process and the organic acid production process are all carried out within one anaerobic digestion tank (40), or an anaerobic digestion tank ( 40) can be performed through equipment divided into two phases, that is, an acid fermentation tank and a methane fermentation tank. At this time, since the specific equipment structure and configuration of the anaerobic digestion tank 40 can appropriately utilize known equipment technology related to anaerobic digestion, detailed description thereof is omitted in the present invention.

In addition, when performing the anaerobic digestion step by dividing it into an acid fermentation step and a methane fermentation step, the optimal condition is that the acid fermentation step is performed at a medium temperature, for example, 30 to 40 ℃, and hydrolysis is performed together in the acid fermentation tank. Considering this, it is recommended to maintain pH between 4.5 and 6.5, more preferably between pH 5.5 and 6.5. Additionally, the methane fermentation step may be performed at medium temperature digestion or high temperature digestion, for example, at 50 to 55°C, and in this case, the preferred pH is 6.5 to 7.5, more preferably 7.0 to 7.5.

On the other hand, scum or foam generated at the interface of the digestive waste fluid, which may occur during the anaerobic digestion stage, reduces the fermentation efficiency of methane fermenting microorganisms, which may result in methane fermentation not being carried out properly and reducing the amount of methane produced. In particular, foam is caused by an increase in the partial pressure of carbon dioxide generated through anaerobic digestion in the sealed anaerobic digestion tank 40. Considering that the anaerobic digestion tank 40 is sealed to maintain the anaerobic state, it is not easy to lower the partial pressure of carbon dioxide. . Accordingly, the present invention lowers the partial pressure of carbon dioxide by converting the generated carbon dioxide back into the bicarbonate ion state in the digestive waste fluid and dissolving it, thereby preventing the decline in methane fermentation due to foam generation and at the same time increasing alkalinity due to the increase in bicarbonate ions, thus reducing the anaerobic digestion tank (40). By strengthening my pH buffering capacity, there is an advantage in minimizing pH shock caused by a decrease or increase in pH. For this purpose, the present invention provides an enzyme converter capable of converting carbon dioxide in the anaerobic digestion tank (40).

According to one embodiment of the present invention, the enzyme converter may include a porous mineral support and carbonic anhydrase immobilized on the porous mineral support.

The carbonic anhydrase enzyme is a biocatalyst that converts carbon dioxide into bicarbonate ions, and is more environmentally friendly than carbon dioxide absorbents. Carbonic anhydrase enzyme can theoretically convert one million carbon dioxide molecules per second into bicarbonate ions, thereby rapidly converting carbon dioxide molecules into bicarbonate ions. It is very suitable for conversion of increasing carbon dioxide. In particular, in order to reduce the partial pressure of carbon dioxide, it may be considered to provide a carbon dioxide absorbent in the anaerobic digestion tank (40). However, typical carbon dioxide absorbents have a pH of 9 to 12 and are strongly alkaline, so the pH of the digested waste fluid in the anaerobic digestion tank (40) If it increases excessively, there is a risk of inhibiting the methane fermentation of methane fermenting bacteria. However, since carbonic anhydrase does not cause pH changes like carbon dioxide absorbers, it can prevent the decline in methane fermentation of methane fermenting bacteria.

If the carbonic anhydrase is a known enzyme that has the function of promoting the reaction of converting carbon dioxide into bicarbonate ions, it can be used without limitation. For example, any one or more of wild-type carbonic anhydrase and carbonic anhydrase mutants may be used. It can be included. At this time, the wild-type carbonic anhydrase may be an enzyme that normally exists naturally in living organisms such as animals and plants, and may be one or more types selected from the group consisting of α-type, β-type, γ-type, δ-type and ε-type. And/or it may be a product that mimics an enzyme existing in the body, artificially recombined the enzyme, or a combination of these and carbonic anhydrase enzyme that exists in the body. The artificially recombinant carbonic anhydrase may be known, so the present invention does not specifically limit its amino acid sequence. In addition, the carbonic anhydrase variant is one in which part or all of the amino acid sequence of the naturally existing carbonic anhydrase enzyme has been modified, and at the same time has the basic functions of carbonic anhydrase enzyme and does not possess the naturally existing carbonic anhydrase enzyme. Physical properties such as heat resistance may be advantageously improved, and the present invention does not specifically limit the amino acid sequence thereof.

The carbonic anhydrase described above may be provided in the digestion waste fluid in the anaerobic digestion tank 40 in a free state, but in this case, it is difficult to control the stability of the carbonic anhydrase and the position of the carbonic anhydrase, thereby achieving a sufficient carbon dioxide conversion effect. This can be difficult to do. In other words, carbon dioxide conversion can be most actively performed at the interface of the gas space where the gas containing carbon dioxide and the digested waste fluid in the anaerobic digestion tank 40 with a high concentration of carbon dioxide are located, and a high concentration of carbonic anhydrase in a free state is added to the interface. Positioning control is close to impossible.

Accordingly, according to one embodiment of the present invention, the carbonic anhydrase enzyme is provided in the anaerobic digestion tank (40) in a state fixed to a mineral porous support, and through this, it stably exerts enzyme activity within the anaerobic digestion tank (40). It can be advantageous. In addition, the mineral porous support may have a specific gravity of less than 1.0, which allows the mineral porous support to float at the interface between the digestive waste fluid and the gas space, which may be advantageous for positioning carbonic anhydrase enzyme at the interface.

In addition, according to one embodiment of the present invention, the mineral porous support is advantageous in that it is implemented with a specific gravity of less than 1.0, and reduces the activity of anaerobic microorganisms due to various toxic substances present in the liquid waste supplied to the anaerobic digestion tank (40). It may be a porous sintered body in which mineral components including pumice and red clay that can adsorb toxic substances are sintered to prevent it. The pumice stone, together with red clay, can more easily produce a porous sintered body with a specific gravity of less than 1.0. In addition, red clay contains various types of minerals such as quartz, feldspar, clay minerals, iron oxide minerals, and gibbsite, and its chemical components include silicon dioxide, aluminum trioxide, iron trioxide, magnesium oxide, potassium oxide, water, and It may also contain small amounts of other ingredients. Red clay can absorb toxic substances such as heavy metals and ammonia, which are known to inhibit anaerobic digestion, and prevent a decrease in anaerobic digestion efficiency due to a decrease in the activity of anaerobic microorganisms due to toxic substances. there is. Preferably, the porous sintered body may be a mixture of pumice and red clay at a weight ratio of 1: 0.5 to 0.8, and if the red clay is provided in a weight ratio of less than 0.5, the increase in anaerobic digestion efficiency may be minimal, and if the red clay exceeds 0.8 weight ratio, the specific gravity may be The production efficiency of porous sintered bodies implemented at less than 1.0 may decrease.

In addition, the porous sintered body may further contain glass powder such as silica sand or soda ash, through which the mechanical strength of the sintered body can be increased. At this time, it is preferable that the glass powder is included in an amount of 40 to 60 parts by weight based on the total weight of pumice and red clay of 100 parts by weight. If the glass powder is less than 40 parts by weight, the improvement in mechanical strength may be minimal, and if it exceeds 60 parts by weight, the improvement in mechanical strength may be relatively small. As the weight of pumice and red clay decreases, it may be difficult to achieve a specific gravity of less than 1.0, or there is a risk that the adsorption performance of toxic substances may decrease.

In addition, the porous sintered body can be obtained by molding the above-described slurry of red clay, pumice, and glass powder mixed with a pore forming agent into a predetermined size and shape and then sintering at 700 to 1000°C. The pore-forming agent is used to manufacture the sintered body into a porous structure, and is thermally decomposed through the sintering process to form pores. Pore-forming agents known to have this function can be used without limitation, for example, polyacrylamide, Polystyrene, sodium polyacrylate, etc. can be used.

In addition, the porous sintered body is preferably implemented with a porosity of 45 to 70%, which is advantageous for achieving the purpose of the present invention.

In addition, carbonic anhydrase is fixed on the porous sintered body described above, and carbonic anhydrase may be fixed on the outer surface and inside the pores of the porous sintered body. The fixation may be, for example, physical adsorption or fixation using a binder, such as glutaraldehyde, but the present invention is not particularly limited thereto.

On the other hand, when the anaerobic digestion tank is provided in two phases, the enzyme converter may be provided in the methane fermentation tank. Through this, the carbon dioxide generated during fermentation can be converted into bicarbonate ions (HCO ₃ ^- ) to increase the concentration of bicarbonate ions in the methane fermentation tank. The increased bicarbonate ions increase the ability to buffer the pH of the methane fermentation tank, thereby increasing the concentration of bicarbonate ions in the acid fermentation tank. Even in the case of excessive supply of primary anaerobic digestion waste fluid containing organic acids, the shock of pH drop can be alleviated and conditions of pH 6.5 or higher can be maintained, thereby enabling stable methane fermentation.

In addition, the anaerobic digestion tank 40 equipped with an enzyme converter can be digested at a medium temperature or at a high temperature, but it is preferable that digestion is performed at a medium temperature in order to prevent inhibition of the activity of the carbonic anhydrase enzyme provided in the enzyme converter.

In addition, according to one embodiment of the present invention, in order to prevent the generation of scum due to residual oil in the liquid waste supplied to the anaerobic digestion tank 40 and the resulting decrease in methane production, a separate oil layer is not formed in the upper layer of the digested waste fluid. The anaerobic digestion tank 40 may be further equipped with a nonionic surfactant release device capable of releasing the nonionic surfactant so that it can be dissolved in the digestive waste fluid. The nonionic surfactant release device may be configured by applying known technology to remotely control the amount of nonionic surfactant released from the outside by determining the degree of scum generation or oil layer formation inside the anaerobic digestion tank 40. , the present invention does not specifically limit the specific configuration of the emitting device itself.

Meanwhile, a non-ionic surfactant is used to remove the oil layer. If an amphoteric surfactant, anionic surfactant, or cationic surfactant is used, the oil remaining in organic waste, especially liquid waste derived from food waste, is used. Removal of the oil layer may not be smooth. More preferably, the non-ionic surfactant may have an HLB value of 11 to 15, and more preferably, the non-ionic surfactant may have an HLB value of 13 to 15, and through this, the non-ionic surfactant may be used to remove oil from residual oil in liquid waste derived from food waste. Layer removal can be much easier.

In addition, gas containing methane, which is biogas generated through anaerobic digestion, flows out through a separate outlet connected to the anaerobic digestion tank 40, and then removes water vapor through a biogas treatment facility, for example, a condenser 80, After going through the process of removing sulfur dioxide through a desulfurization facility and removing carbon dioxide through a carbon dioxide capture device, it is stored in a separate storage tank, a boiler to maintain the temperature necessary for anaerobic digestion, or drying solid waste obtained by separating solid and liquid together with liquid waste. It can be used directly or indirectly as an energy source for operating a heat source such as the dryer 70.

Meanwhile, the anaerobically digested liquid waste may be further subjected to a digestion sludge removal step using a known method before being introduced into the aerobic digestion step described later. Digested sludge can be removed by a conventional method of collecting settled digested sludge. In addition, the collected digested sludge can be further subjected to a solid-liquid separation step using a dehydration device, and the obtained solid sludge can be stored separately and used as a resource for reintroducing anaerobic microorganisms into the anaerobic digestion tank 40, or dried. After going through a composting process, it can be used as fertilizer or recycled as solid fuel. In addition, the dehydrated liquid obtained in the digested sludge solid-liquid separation step can be combined with the anaerobic digested waste fluid and input into the aerobic digestion step described later. In addition, condensate generated during drying of solids may be inputted into an aerobic digestion step described later, stored in a separate storage tank, or inputted into a separate anaerobic digestion tank 40 and subjected to an anaerobic digestion step, and the present invention specifically provides for this. It is not limited.

Next, the anaerobically digested liquid waste is put into the aerobic digestion step to reduce the high COD and BOD in the anaerobically digested liquid waste. The aerobic digestion step refers to the digestion of organic matter remaining in the anaerobically digested liquid waste using aerobic microorganisms, and can be performed using aerobic digestion equipment known in the art, and the present invention is not particularly limited thereto. For example, as the aerobic digestion step requires oxygen, a separate aeration tank may be placed in front of the aerobic digestion tank (50) or an aeration device may be provided in the aerobic digestion tank (50). In addition, the specific digestion conditions of the aerobic digestion step may be selected differently depending on the type of aerobic microorganisms provided, so the present invention is not particularly limited thereto and can be performed by appropriately utilizing known conditions.

Meanwhile, an anaerobic fermentation step may be further performed before the aerobic digestion step. The anaerobic fermentation step can be performed through a known anaerobic tank. In addition, when an anoxic tank is provided, the known A2O method can be used. In the case of the A2O method, the tanks are arranged in the order of the anaerobic digestion tank (40), the anoxic tank, and the aerobic digestion tank (50), and through the application of the anoxic tank, the returned sludge is The amount of nitrate nitrogen re-supplied to the anaerobic tank can be minimized. The anaerobic digestion tank (40) and the anoxic tank perform a denitrification process, and the aerobic digestion tank (50) performs a nitrification process. Influent water and returned (activated) sludge (external circulation) are supplied to the anaerobic digestion tank (40), and the aerobic digestion tank (50) performs a nitrification process. Activated sludge (internal circulation) can be circulated in an anoxic tank.

The A2O method can remove both nitrogen and phosphorus, provides the alkalinity necessary for nitrification, has good sludge settling properties, and has the advantage of being relatively simple to operate, while RAS containing nitrate nitrogen is used in an anaerobic tank. At this time, it affects the phosphorus removal ability, nitrogen removal is limited by the internal return ratio, and the BOD/P ratio is higher compared to the AO method, that is, when composed of an anaerobic digester (40) and an aerobic digester (50). It should be noted that there are cases where external carbon sources must be input because it is necessary.

The rough treated water that has passed through the aerobic digestion tank (50) described above may be discharged after undergoing sewage treatment, or may be supplied to the filtration step, and the filtrated water that has gone through the filtration step may be discharged through a sewer pipe or together with the condenser (80). It can also be supplied as cooling water to the cooling tower to form a zero-discharge system.

The filtration step can be performed using a known filtration tank 60. As an example, the filtration tank 60 may be appropriately composed of a sedimentation tank, a sand tank, and/or an activated carbon filtration tank 60, and since the equipment of each specific tank can use known equipment, the present invention omits the detailed description thereof. . Meanwhile, the filtration step can be performed using a membrane filtration tank 60 equipped with a filtration membrane, and the membrane filtration tank 60 may be equipped with a typical filtration membrane such as UF, NF, RO, etc., and the present invention specifically provides for this. It is not limited.

Meanwhile, the organic waste treatment method and treatment device include a drying step of drying the solid waste separated through the solid-liquid separator 20 described above, a dryer 70 for this, and condensate production to condense the vapor generated in the drying step. It may further include a step and a condenser 80 therefor.

The dryer 70 lowers the moisture content of the solid waste separated by the solid-liquid separator 20 to at least 10% or less. The drying temperature of the dryer 70 may be, for example, 100 to 150°C. , drying time may be 2 to 3 hours, but is not limited thereto.

In addition, the solid waste for which the drying operation is completed by the dryer 70 can be shredded and sorted. In this case, a vibration separator using a mesh net or a magnetic separator using magnetic force is preferable as a sorter for solid waste, but it should be noted that even if a specific gravity sorter using specific gravity difference is applied, it is included in the technical scope of this institute. In addition, the crushed and selected solid waste is recycled as a raw material for fertilizer or feed, and a dried matter discharge line may be further provided to supply the dried matter to the fertilizer or feed manufacturing process.

In addition, a vapor processor may be further provided to recycle the vapor generated during drying through the dryer 70, and the vapor processor includes a condenser 80 for heat exchanging vapor, and cooling the temperature of the condensed condensate. It may further include a cooling tower for

The obtained condensate may be stored in a separate storage tank, but the condensate may be supplied to the anaerobic digestion tank (40) or the aerobic digestion tank (50) to remove nitrogen or sulfur dissolved in the condensate, such as ammonia or hydrogen sulfide. Let it be known.

On the other hand, biogas generated through the anaerobic digester 40 can be supplied to the heat source supplier 90, which generates various heat sources required when performing the treatment method of the present invention, so that organic waste can be removed without the supply of a separate external energy source. Since it is possible to process organic waste, it is possible to process organic waste at reduced costs.

The present invention will be described in more detail through the following examples, but the following examples do not limit the scope of the present invention, and should be interpreted to aid understanding of the present invention.

<Example 1>

Organic waste, which is food waste, was put into a crushing separator and then put into a solid-liquid centrifuge to obtain liquid waste. After removing the oil from the obtained liquid waste through a three-phase centrifuge, the liquid waste from which the oil was removed was introduced into an anaerobic digestion tank consisting of two phases, an acid fermentation tank and a methane fermentation tank, and the acid fermentation tank had pH 4.5 and a temperature of 35°C. The acid fermentation process was performed. Meanwhile, after independent acid fermentation in the acid fermentation tank for about 10 days or more, the acid-fermented primary anaerobic digestion waste fluid containing organic acids is continuously supplied to the methane fermentation tank at a constant flow rate in the methane fermentation tank. The enzyme converter manufactured in the preparation example below was placed at the interface between the supplied digestive waste fluid and the gas space to enable methane fermentation. After performing the anaerobic digestion step, the gas containing methane produced was supplied to a biogas obtaining device equipped with a plurality of gas separation membranes capable of removing water vapor, carbon dioxide, and sulfur, respectively, and the methane gas was stored separately, and anaerobic digestion was performed. The precipitated digested sludge was dehydrated and stored as solid waste, and the liquid waste was filtered through a regular aerobic digestion tank and filtration tank to treat organic waste.

* Preparation example

After mixing pumice and red clay at a weight ratio of 1:0.6, glass powder obtained from a melted mixture of silica sand and soda ash was added in an amount of 60 parts by weight based on 100 parts by weight of the total weight of pumice and red clay, and a polystyrene pore former was added by mixing the glass powder with the pumice stone. After adding 400 parts by weight of the total weight of red clay (100 parts by weight), water was mixed and stirred, extruded, dried, and cut to produce a pellet-shaped molded body. The manufactured molded body was charged into a firing furnace and fired at a temperature of 850°C to obtain a mineral porous support with a porosity of 63%, specific gravity of 0.89, a diameter of 2 mm, and a length of 1 cm.

Afterwards, the obtained mineral porous support was added to a phosphate buffer solution in which carbonic anhydrase was dispersed at a concentration of 1 mg/ml, carbonic anhydrase was adsorbed on the mineral porous support, and then washed to obtain an enzyme converter.

<Example 2>

The same procedure as in Example 1 was carried out, but the specific gravity of the mineral porous support of the enzyme converter prepared in the preparation example was changed to exceed 1.0 to proceed with anaerobic digestion, and then the organic waste was treated through aerobic digestion and filtration steps.

<Example 3>

The same procedure as in Example 1 was carried out, but a nonionic surfactant release device capable of releasing a nonionic surfactant (poly sorbate 85) with an HLB value of 11 was installed in the methane fermentation tank to release the nonionic surfactant during methane fermentation. Anaerobic digestion was performed, and the organic waste was then treated through aerobic digestion and filtration steps.

<Examples 4 to 9>

The same procedure as in Example 2 was performed, except that anaerobic digestion was performed by adding a surfactant according to Table 1 below instead of a nonionic surfactant, and then the organic waste was treated through aerobic digestion and filtration steps.

type product name HLB Example 4 cationic CTAB 10 Example 5 anionic SLS 40 Example 6 amphiphilic Tego 13 Example 7 nonionic sorbitan laurate 8.6 Example 8 nonionic Tween80 15.0 Example 9 nonionic Tween 20 16.7

<Comparative Example 1>

The same procedure as in Example 1 was performed, but organic waste was treated through anaerobic digestion, aerobic digestion, and filtration steps without including an enzyme converter.

<Experimental example>

The following physical properties were evaluated for the organic waste treatment devices and treatment methods through Examples 1 to 9 and Comparative Example 1, and the results are shown in Table 2 below.

1. Measurement of yield of methane gas produced

The amount of methane gas obtained 25 days after performing the anaerobic digestion step was measured, and the results of the remaining Examples and Comparative Example 1 were converted into relative yields based on the measurement results of Example 1 as 100%.

2. Evaluation of pH buffering effect

The flow rate of the primary anaerobic digestion liquid supplied to the methane fermentation tank was increased to 2.5 times after 20 days, and the amount of methane gas obtained 30 days after performing the anaerobic digestion step was measured, and the measurement results of Example 1 were 100% Based on this, the results of the remaining Examples and Comparative Example 1 were converted into relative yields.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Comparative Example 1 Enzyme converter availability/specific gravity of mineral porous support ○/
0.89 ○/
greater than 1.0 ○/
0.89 ○/
0.89 ○/
0.89 ○/
0.89 ○/
0.89 ○/
0.89 ○/
0.89 Not equipped/- Type of surfactant added (HLB value) Not entered Not entered Nonionic (11.0) Cationic (10) Anionic (40) Amphiphilic (13) Nonionic (8.6) Nonionic (15.0) Nonionic (16.7) Not entered Methane yield (%) 100 70.1 138.9 101.6 94.1 106.0 118.3 156.5 125.9 60.8 pH buffering effect (methane yield (%)) 100 29.0 Not rated Not rated Not rated Not rated Not rated Not rated Not rated 28.5

As can be seen from Table 2 above,

It can be confirmed that Examples 1 and 2 equipped with an enzyme converter have a significantly superior effect in terms of methane yield compared to Comparative Example 1. However, the enzyme converter equipped with a mineral porous support with a specific gravity exceeding 1.0 did not convert much carbon dioxide as it settled in the digestion waste fluid, so the methane yield was significantly less than that of Example 1, and the pH buffering effect was similar to that of Comparative Example 1. It can be seen that the pH buffering effect is minimal in the amount converted to .

In addition, in Examples 3, 7 to 9, in which a non-ionic surfactant was added, the methane yield was significantly increased compared to Example 1 in which the surfactant was not added, and through this, the generation of scum in the oil layer was suppressed and methane was produced. It can be expected that fermentation efficiency has increased.

In addition, it can be seen that even when surfactants are added, the increase in methane yield in Examples 4 to 6, in which cationic, anionic and amphoteric surfactants are added, is insignificant compared to Examples 3 and 7 to 9.

Although one embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiment presented in the present specification, and those skilled in the art who understand the spirit of the present invention can add components within the scope of the same spirit. , other embodiments can be easily proposed by change, deletion, addition, etc., but this will also be said to be within the scope of the present invention.

Claims (8)

A crushing separator that crushes organic waste and selects foreign substances;
A solid-liquid separator that separates the crushed and selected organic waste into solid waste and liquid waste, respectively, through the crusher and sorter;
A three-phase separator that selectively removes oil in the separated liquid waste;
An anaerobic digester that anaerobically digests liquid waste from which oil has been selectively removed and produces biogas;
An aerobic digestion tank that aerobically digests anaerobic digestion waste fluid; and
Including a filtration tank for filtering foreign substances remaining in the aerobic digestion waste fluid discharged from the aerobic digestion tank,
The anaerobic digestion tank is equipped with an enzyme converter for conversion of carbon dioxide generated during anaerobic digestion and a nonionic surfactant release device for removing the oil layer formed on the liquid waste,
The enzyme converter is a porous sintered body in which mineral components including pumice and red clay are sintered, and includes a mineral porous support having a specific gravity of less than 1.0 and carbonic anhydrase fixed on the mineral porous support, and the nonionic surfactant releasing device is HLB. An organic waste treatment device with improved biogas production, characterized in that it emits a nonionic surfactant with a value of 11 to 15. According to paragraph 1,
A dryer for drying the solid waste; and
An organic waste treatment device with improved biogas production, further comprising a condenser for condensing vapor generated in the dryer. According to paragraph 2,
The dryer is an organic waste treatment device with improved biogas production that operates by using biogas produced in an anaerobic digester as a direct or indirect energy source. delete delete delete A shredding and sorting step in which organic waste is shredded and foreign substances are selected;
A solid-liquid separation step of dehydrating the organic waste supplied in the crushing and sorting step to separate it into solid waste and liquid waste;
An oil removal step of selectively removing oil by three-phase centrifugation of the liquid waste separated in the solid-liquid separation step;
An anaerobic digestion step of anaerobically digesting liquid waste from which oil has been selectively removed and producing biogas;
An aerobic digestion step of aerobically digesting anaerobic digestion waste fluid; and
It includes a filtration step of filtering out foreign substances in aerobic digestive lung fluid,
The anaerobic digestion step is performed so as to convert carbon dioxide generated through anaerobic digestion into bicarbonate ions and release a nonionic surfactant with an HLB value of 11.0 to 15.0 for removal of the oil layer formed on the liquid waste. ,
The conversion of carbon dioxide into bicarbonate ions is a porous sintered body in which mineral components including pumice and red clay are sintered, and is carried out through an enzyme converter comprising a mineral porous support having a specific gravity of less than 1.0 and carbonic anhydrase fixed on the mineral porous support. Organic waste disposal method with improved biogas production.
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