JP2007260538A - Organic waste treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an environment-friendly and efficient organic waste treatment system which is systematized by properly combining a methane fermentation device, a carbonizing device, and, if necessary, a generating set, so that their characteristics are used and their defects are mutually compensated. <P>SOLUTION: In the treatment system of organic waste 4 divided into liquid organic matter 5, a solid and liquid mixed organic matter 6, and a solid organic matter 7, the methane fermentation device 2 which performs the methane fermentation treatment of the liquid organic matter 5 to generate methane fermentation gas, and supplies the generated methane fermentation gas as fuel for power generation and the like, the carbonizing device 1 which heats and carbonizes the solid organic matter 7 to generate a carbonized material and dry-distilled gas, and a solid-liquid separation device 8 which separates the solid and liquid mixed organic matter 6 into the liquid organic matter and the solid organic matter, and supplies the liquid organic matter and the solid organic matter respectively to the methane fermentation device 2 and the carbonizing device 1 are properly combined and systematized. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic waste treatment system that combines a methane fermentation apparatus and a carbonization apparatus.

Conventionally, methane fermentation treatment has been used as a waste biomass treatment system, and many methods have been proposed for generating power using methane fermentation gas generated by methane fermentation treatment and recovering energy. This system uses microorganisms and is an excellent system that can process waste and recover energy at a relatively low cost. However, this system has a problem with the waste liquid after methane fermentation. The waste liquid cannot be discharged as it is because it contains a high concentration of hardly decomposable organic matter. Therefore, various waste liquid treatment methods such as treatment with aerobic microorganisms, biological oxidation, and denitrification treatment have been proposed (see, for example, Patent Documents 1, 2, and 3).
Japanese Patent No. 3064272 Japanese Patent No. 3406535 Japanese Patent No. 3533064

  In this way, in methane fermentation treatment, it is difficult to treat the waste liquid to below the regulation value of wastewater, as well as the problem of disposal of sludge generated from wastewater treatment, the cost of desulfurization of methane fermentation gas, and treatment There are problems such as bad odor generated in the process. In addition, the waste biomass that is the object of treatment is a waste with a large amount of liquid water such as livestock excreta, and therefore has a drawback that the energy that can be recovered is small.

  An object of the present invention is to provide an organic waste treatment system capable of solving the above-mentioned various problems by properly combining a methane fermentation apparatus, a carbonization apparatus, and a power generation apparatus as necessary. Is to provide.

  The organic waste treatment system of the present invention is an organic waste treatment system classified into liquid organic matter, solid-liquid mixed organic matter, and solid organic matter, and the liquid organic matter is subjected to methane fermentation treatment to produce methane fermentation gas. A methane fermentation apparatus that generates and supplies the generated methane fermentation gas as a fuel for power generation, the carbonization apparatus that heats and carbonizes the solid organic matter, and generates carbide and dry distillation gas; and the solid-liquid mixing The organic substance is separated into a liquid organic substance and a solid organic substance, and the liquid organic substance is provided with a methane fermentation apparatus, and the solid organic substance is provided with a solid-liquid separation apparatus that supplies the solid organic substance to a carbonization apparatus.

  In the present invention, the methane fermentation apparatus has a waste liquid treatment apparatus for the waste liquid after methane fermentation, and in the adsorption treatment apparatus for organic matter in the treated water separated from sludge by the waste liquid treatment apparatus, the carbide generated by the carbonization apparatus Is used as an adsorbent.

  Further, in the present invention, the solid-liquid separation device is used for solid-liquid separation of the carbide broken through by the adsorption of organic matter, and the separated solid waste is supplied to the carbonization device to be carbonized again to be reusable. It is also used as a breakthrough carbide recycling facility.

  In the present invention, the carbide that adsorbs the organic substance is a carbide that is carbonized at a carbonization temperature of 500 ° C. or higher.

  Moreover, in this invention, the methane fermentation apparatus has a desulfurization apparatus which desulfurizes the produced | generated methane fermentation gas, The carbide | carbonized_material produced | generated by the carbonization apparatus is used as a desulfurization agent of this desulfurization apparatus.

  Further, in the present invention, it has a water washing device for removing the adhering sulfuric acid by washing the carbide having a reduced desulfurization ability by desulfurization treatment, and the solid-liquid separation device separates and separates the washed carbide by solid-liquid separation. It is also used as a waste desulfurizing agent regeneration facility for supplying solid waste to a carbonization device, carbonizing it again and reusing it for reuse.

  Moreover, in this invention, the carbide | carbonized_material produced | generated by the carbonization apparatus was used for the adsorption agent in the deodorization apparatus of malodorous gas.

  Moreover, in this invention, the deodorizing apparatus which adsorbs malodorous gas is used also as a fertilizer supply apparatus which supplies the carbide | carbonized_material broken through by adsorption as fertilizer.

  Moreover, in this invention, a methane fermentation apparatus has the boiler for methane fermentation tank heating, and uses the carbide | carbonized_material produced | generated by the carbonization apparatus as a fuel of the said boiler.

  Moreover, in this invention, it has the mixing apparatus which mixes the carbide | carbonized_material produced | generated with the carbonization apparatus, and the waste liquid after the methane fermentation in a methane fermentation apparatus, and produces | generates a fertilizer, The organic waste of Claim 1 characterized by the above-mentioned. Material processing system.

  Moreover, in this invention, while using the carbonization gas obtained from a carbonization apparatus as a heating fuel of the carbonization furnace which comprises a carbonization apparatus, it mixes with methane fermentation gas and supplies as fuel gas for electric power generation.

  Moreover, in this invention, while using the carbonization gas obtained from a carbonization apparatus as a fuel for heating of the carbonization furnace which comprises a carbonization apparatus, it is used as a fuel of the boiler for the methane fermentation tank heating in a methane fermentation apparatus.

  Moreover, in this invention, the waste gas used for the heating of the carbonization furnace which comprises a carbonization apparatus is used for the heating of the methane fermentation tank in a methane fermentation apparatus.

  Further, in the present invention, the solid-liquid separation device has a drying device for drying the solid content obtained by solid-liquid separation of the solid-liquid mixed organic matter, and the exhaust gas used for heating the carbonization furnace constituting the carbonization device, Used as a heat source for the drying apparatus.

  Further, in the present invention, the waste liquid treatment apparatus for waste liquid after methane fermentation has a heating apparatus for concentrated sludge generated by waste liquid treatment, and the exhaust gas used for heating the carbonization furnace constituting the carbonization apparatus is used for the concentrated sludge. Used as a heat source for heating.

  Further, in the present invention, the carbonization apparatus has a combustion furnace for heating the carbonization furnace, sucks high-concentration malodorous gas generated from waste etc. with a suction blower via a duct, and introduces it into the combustion furnace for combustion. It is used as an air source, and odor components are oxidatively decomposed by the heat of combustion.

  According to the present invention, a methane fermentation apparatus, a carbonization apparatus, and a power generation apparatus as necessary are combined with each other to utilize their respective characteristics and to make up for each other's disadvantages, so that the organic waste is efficient in consideration of the environment. Can be processed. That is, it is possible to solve the problems of methane fermentation treatment, such as treatment of waste liquid after methane fermentation, disposal of generated sludge, bad odor, and low recoverable energy. That is, the organic waste is separated into liquid and solid, the liquid waste is treated with a methane fermentation apparatus, and the sludge generated from the waste liquid treatment after methane fermentation is carbonized. On the other hand, solid waste is treated with a carbonization apparatus to recover valuables as carbides, and the resulting carbides are used to treat waste liquid after methane fermentation, deodorize bad odors, and the like. For the point where the energy that can be recovered is small, the recovered energy of the entire system is increased by carbonizing the solid organic waste. In this way, by properly combining methane fermentation equipment and carbonization equipment into a system, the amount of energy recovered can be increased, and volume reduction, stabilization, long-term storage, and removal of bad odor can be achieved by carbonization of waste. An excellent organic waste treatment system.

  Hereinafter, an embodiment of an organic waste treatment system according to the present invention will be described with reference to the drawings.

  FIG. 1 shows an outline of an organic waste treatment system according to this embodiment. This organic waste treatment system is mainly composed of a carbonization device 1, a methane fermentation device 2, and a power generation device 3. Various organic wastes 4 are classified into liquid waste (organic matter) 5, solid-liquid mixed waste (organic matter) 6, and solid waste (organic matter) 7 at the time of acceptance, and are temporarily stored in each storage tank. The liquid waste 5 is, for example, a liquid substance such as livestock excrement manure, waste cooking oil, and alcohol production waste liquid. The solid-liquid mixed substance 6 is a substance having a relatively high water content such as sludge, raw garbage, food processing residue, and marine waste. The solid waste 7 is a solid substance having a low water content, such as building waste, lumber residue, pruned wood, thinned wood, waste paper, bacas, rice straw, rice husk, and plastic.

  The solid-liquid mixed waste 6 is separated into a liquid substance and a solid substance by a solid-liquid separator 8, and the liquid substance is mixed with the liquid waste 5 and the solid substance is mixed with the solid waste 7. Examples of the solid-liquid separation device 8 include filtration separation using a screen, squeezing separation using a roller press, belt press, screw press, and the like, and centrifugation using a centrifuge. Among these, the pressure separation by a screw press has a relatively simple structure and can separate a solid content and a liquid content with high accuracy. Alternatively, solid-liquid separation combining these is also possible.

  The carbonization apparatus 1 for processing the solid waste 7 is mainly composed of a carbonization furnace 9, a combustion furnace 10, and an exhaust gas treatment apparatus 11. Carbide 12 is obtained as valuable material, and dry distillation gas 13 and carbonization furnace exhaust gas 14 are obtained as energy. On the other hand, the methane fermentation apparatus 2 that processes the liquid waste 5 includes a methane fermentation tank 15, a waste liquid treatment apparatus 16, an aggregation treatment apparatus 17, a gas holder 18, and a desulfurization treatment apparatus 19. Methane fermentation gas 20 is obtained as a valuable material, and treated water 21, sludge 22, malodorous gas 23, and the like are generated from waste liquid treatment device 16 and the like. The power generation device 3 using the methane fermentation gas 20 generated by the methane fermentation treatment as a fuel gas is generally composed of a pretreatment device 24, a reformer 25, a power generation device main body 26, and an inverter 27, and uses electricity 28, hot water as energy. 29 is obtained.

  A method of solidifying the liquid waste 5 by treating it as a solid substance is also conceivable. However, most of the liquid waste 5 has a water content of 90% or more. Is preferable. Therefore, as the liquid treatment method, the above-described methane fermentation treatment which is a treatment with microorganisms and can recover energy is preferable. Since the methane fermentation apparatus 2 is a relatively simple facility, it can be easily managed, and the generated methane fermentation gas can be used for power generation. The electric power obtained by the power generation is supplied into and out of the organic waste treatment system facility.

  On the other hand, the solid waste 7 may be pulverized and mixed with the liquid and subjected to methane fermentation treatment. However, anaerobic microorganisms can be digested in methane fermentation by a liquid substance, and the pulverized one is liquid. It takes time to be digested until it is not possible. For this reason, the solid waste 7 is carbonized as it is by the carbonization apparatus 1 described above, and is recovered as a valuable material or energy.

Table 1 shows typical examples of water content and lower heating value of various wastes. Generally, the higher the water content, the lower the lower heating value. In other words, in a power generation system that uses methane fermentation gas produced by methane fermentation from conventional liquid waste and solid-liquid waste, it can be obtained for a large scale because of its high water content and low organic matter content. There was a disadvantage that the proportion of energy was small. However, in this organic waste treatment system, carbonized solid waste with a low moisture content and a high proportion of organic matter increases the energy gained and effectively uses the obtained carbide in the system. it can.

  Next, a general configuration of each of the devices 1, 2, and 3 will be described.

  The carbonization apparatus 1 is classified into a carbonization method such as an internal combustion type (direct heating), an external combustion type (indirect heating), a continuous type, a batch type, etc. In order to obtain an excellent homogeneous carbide, an external combustion type (indirect type) (Continuous heating) is used. That is, in carbonization, carbonization temperature and carbonization time management are important. However, in the continuous type of the external combustion type (indirect heating), the conditions can be easily controlled, and an excellent carbide can be obtained. The external combustion type is configured by a rotary kiln system, for example.

  FIG. 2 shows an example of this rotary kiln type continuous carbonization apparatus. In FIG. 2, the carbonization apparatus 1 is mainly composed of a carbonization furnace 9 and a combustion furnace 10. The rotary kiln type continuous carbonization furnace 9 has a double cylinder structure of an inner cylinder and an outer cylinder. A heating gas (combustion gas) is supplied from the combustion furnace 10 between the inner cylinder and the outer cylinder, and the carbonization temperature is increased. Controlling. Carbonization temperature shall be 500 degreeC or more.

  After the solid waste 7 is supplied to the input hopper 30, it is supplied into the inner cylinder (rotary cylinder) 32 of the rotary kiln by the input screw conveyor 31 or the like. On the inner surface of the inner cylinder 32, a plurality of scraping bars 33 are installed. Therefore, when the inner cylinder 32 rotates, the solid waste 7 is lifted up by the scraping bar 33 and then falls from the top side to the bottom. In this way, the solid waste 7 gradually moves to the discharge side while being constantly stirred in the inner cylinder 32, and heat exchange is performed by heat applied from the outside during that time, and the solid waste 7 is uniformly carbonized. Carbonization time is 15-60 minutes.

  The uniformly carbonized carbide 12 is discharged by a discharge screw conveyor 34. On the other hand, the dry distillation gas 13 generated by the thermal decomposition of the solid waste 7 inside the inner cylinder 32 is supplied to the burner 36 provided in the combustion furnace 10 together with the combustion air 35 and burned in the combustion furnace 10. . Thus, the dry distillation gas 13 is burned in the combustion furnace 10 and stays at about 850 ° C. or more for 2 seconds or more. For this reason, the dioxin contained in the dry distillation gas is also decomposed. And it supplies to the space of the inner cylinder 32 and an outer cylinder as heating gas with respect to the carbonization furnace 9. FIG. The heated gas is uniformly heated from the outer surface of the inner cylinder 32, and then dust and the like are removed by the exhaust gas treatment device 11, and then discharged as a carbonization furnace exhaust gas 14 of about 300 to 500 ° C.

  In the external combustion type rotary kiln type continuous carbonization furnace 9, since it is an external combustion type (indirect heating), there is no direct contact between the solid waste 7 (for example, dried sludge) and the heating part, and the outer surface of the inner cylinder 32 Since the whole is indirectly heated, the whole can be heated uniformly and temperature control is also easy. The solid waste 7 is uniformly heated by contacting the heat transfer portion on the inner surface of the inner cylinder 32 while being constantly stirred. For this reason, there is no unevenness in the carbonized state of the carbide, and a homogeneous carbide can be obtained.

  In this way, thermal energy of carbonized material, dry distillation gas of 500 ° C. or higher, and carbonization furnace exhaust gas of about 300 to 500 ° C. can be obtained from the carbonizing apparatus 1 as valuable materials.

  Next, the methane fermentation apparatus 2 will be described with reference to FIG. The methane fermentation apparatus 2 mainly includes a methane fermentation tank 15, a waste liquid treatment apparatus 16, a coagulation sedimentation apparatus 17, a gas holder 18, and a desulfurization apparatus 19.

  In the methane fermentation apparatus 2 configured as described above, the liquid waste 5 containing high-concentration organic substances is first removed from relatively large impurities with a bar screen (not shown) and then temporarily stored in a stock solution tank (not shown). It is stored in. Thereafter, the methane fermentation tank 15 is charged continuously or intermittently. Here, since a high-concentration malodorous gas is generated from the stock solution retention tank, a deodorizing apparatus is required.

  In the methane fermenter 15, the hot water 29 is heated to 30 to 60 ° C. As the hot water, it is preferable to use hot water obtained from the power generation device 3 as described later. In the methane fermentation tank 15, the organic matter is decomposed into methane gas and carbon dioxide gas by the action of anaerobic bacteria during the treatment time of 20 to 30 days. As the methane fermentation treatment, there are low-temperature fermentation, intermediate-temperature fermentation, and high-temperature fermentation, but an intermediate-temperature fermentation method in which the temperature is increased to about 37 ° C is preferable. Although the amount of methane fermentation gas produced is less than that of high-temperature fermentation, it requires less energy for heating and can be treated relatively stably and efficiently.

  The methane fermentation gas 20 mainly composed of methane gas and carbon dioxide gas generated by the methane fermentation treatment is temporarily stored in the gas holder 18 and then sent to the desulfurization device 19 where harmful hydrogen sulfide and the like are removed and fuel is removed. The gas is sent to the power generation device 3 and the like.

  On the other hand, the methane fermentation waste liquid discharged from the methane fermentation tank 15 still contains a large amount of organic matter and cannot be discharged as it is. For this reason, the process by the waste liquid processing apparatus 16 is further performed. That is, after the solid content is removed by a solid-liquid separation screen (not shown), the waste liquid is processed. Waste liquid treatment includes various treatment methods such as microbial treatment, physical treatment, and chemical treatment. Of these, microbial treatment is inexpensive and easy to maintain.

  In the methane fermentation waste liquid to be treated, the decomposition of organic substances by anaerobic microorganisms has been completed by the methane fermentation treatment in the previous stage, and organic substances that cannot be decomposed by anaerobic microorganisms remain. Therefore, the next microbial treatment is preferably a treatment with aerobic microorganisms. In general, activated sludge treatment is employed, and the remaining organic matter is decomposed into carbon dioxide gas and water by the action of aerobic microorganisms and used for the growth of microorganisms.

  In a sedimentation tank (not shown) in the final step of the waste liquid treatment device 16, the sludge and supernatant water are separated, and the supernatant water is sent to the next coagulation treatment device 17. In addition, the sludge is returned to the aeration tank of the waste liquid treatment apparatus 16, and the sludge surplus due to the growth of microorganisms is discharged out of the system as surplus sludge. Excess sludge is concentrated in a sludge concentration tank (not shown) and then separated into supernatant water and sludge, and the sludge is sent to a solid-liquid separator. The supernatant water is returned to the raw water tank of the preceding-stage waste liquid treatment apparatus.

  As the aerobic treatment method, either an aeration method in which sludge is introduced into an aeration tank and air is blown from an aeration tube, or a mechanical aeration method in which air is stirred and brought into contact with air may be used. Further, either a continuous activated sludge treatment method or a batch activated sludge treatment method may be used, and there is no particular limitation, but a method having as high an oxygen dissolution efficiency as possible and a low power consumption is desirable.

  After the organic matter is decomposed by the waste liquid treatment device 16, suspended substances remaining in the water are further removed by the coagulation sedimentation device 17. As the flocculant, several tens to several hundred ppm of polyaluminum chloride, polyiron chloride, aluminum sulfate, or the like is injected to form agglomeration floc to agglomerate and remove suspended substances. Of these, polyaluminum chloride is preferred because it has a wide applicable PH range and little PH degradation.

  As described above, the suspended solids are removed by the coagulation treatment, but the coloring components and the hardly-decomposable organic matter remain, and it is difficult to treat them below the effluent regulation value. If activated carbon is used, it is technically possible to adsorb and remove them. However, since the concentration of organic substances in the waste liquid is high, activated carbon breaks through in a short time. For this reason, a large amount of activated carbon is required, the replacement frequency is high, and the price of the activated carbon is high, so application of the activated carbon treatment is virtually impossible. Therefore, it has been difficult to treat the waste liquid below the regulation value for drainage.

  As described above, the methane fermentation gas 20 is recovered as a valuable material from the methane fermentation apparatus 2, but since the sludge 22, the treated water 21, and the malodorous gas 23 are discharged out of the system, it is necessary to take measures against them.

  Next, the power generator 3 using the methane fermentation gas 20 as fuel will be described with reference to FIG. As the power generation device 3, a diesel engine, a combination of a gas engine and a generator, a fuel cell, or the like can be considered. Of these, the fuel cell is preferable in view of noise, exhaust gas and other environmental effects and power generation efficiency. Therefore, here, power generation by the fuel cell will be described.

  The fuel cell power generation device 3 includes a pretreatment device 24, a reformer 25, a power generation device body 26, and an inverter 27. The pretreatment device 24 is filled with an adsorbent such as activated carbon, and removes trace harmful components that affect power generation from the methane fermentation gas after desulfurization. Next, methane gas is converted into hydrogen gas by the reformer 25 and sent to the power generation apparatus main body 25 as fuel gas. And it generates electric power by making it react with oxygen in the air. The generated direct current is converted into alternating current by the inverter 27 and used for power of facilities and the like in the waste treatment system, and surplus power is supplied to the outside through system linkage.

Moreover, the hot water 29 of about 60 degreeC is obtained with the said electric power generation effect | action. This hot water is used for heating the methane fermentation tank 15 as described above. The methane fermentation gas produced by the methane fermentation treatment is about 200 to 400 liters per kg of organic matter dry weight. In the case of fuel cell power generation, about 1 kW can be generated with 10 m ³ of methane fermentation gas. Thus, the electric power 28 and the hot water 29 are obtained as energy from the power generation equipment 3 and are effectively used in the system.

  Next, referring to FIG. 5, a specific configuration when the carbonization apparatus 1, the methane fermentation apparatus 2, and the power generation apparatus 3 are used to form a system as illustrated in FIG. 1 will be described.

  In the flowchart of the organic waste treatment system shown in FIG. 5, the solid-liquid separation device 8 includes a drying device 37 that dries a solid material obtained by solid-liquid separation of the solid-liquid mixed waste 6. The solid waste 7 is mixed with the solid substance dried by the drying device 37 and then crushed to a few tens of mm or less by a crushing device 38 (for example, a cutting crusher, a compression crusher, an impact crusher, etc.). The After crushing, it is sent to the carbonization apparatus 1 by a feeder (not shown) and the like and supplied to the carbonization furnace 9 in a fixed amount. And it carbonizes at 500 degreeC or more for about 15 to 60 minutes, and is carried out as the carbide | carbonized_material 12. FIG.

  The methane fermentation apparatus 2 includes the waste liquid treatment apparatus 16 and the adsorption treatment apparatus 39 for the waste liquid after methane fermentation as described above. The waste liquid treatment apparatus 16 treats the waste liquid after methane fermentation discharged from the methane fermentation apparatus 15 by activated sludge treatment or the like, and separates it into sludge and treated water in a sedimentation tank which is the final process. The adsorption treatment device 39 adsorbs organic matter contained in the treated water, and the carbide 12 generated by the carbonization device 1 is used as an adsorbent. That is, the carbide 12 obtained from the carbonization apparatus 1 is filled in the adsorption tower of the adsorption treatment apparatus 39, and as shown in FIG. 3, the aerobic activated sludge treatment in the waste liquid treatment apparatus 16 and the coagulation sedimentation apparatus 17 are performed. It is used as an adsorbent for organic matter in the treated water 21 that has undergone the coagulation treatment.

  FIG. 6 shows an example of adsorption characteristics of carbides with respect to organic substances and colored components. In this example, waste liquid obtained by subjecting livestock manure wastewater to methane fermentation treatment at 35 ° C. for 20 days was first treated by the activated sludge method, and PAC 100 mg / l was injected into the treated water as a flocculant. Add 50 g of sludge carbide (500 ° C., carbonization time 20 minutes) to 100 ml of the supernatant water after flocculation, stir and let stand overnight, filter the supernatant with filter paper, separate into 10 mm cells, ultraviolet part (260 nm) And the absorbance of the visible part (420 nm) was measured. The ultraviolet part (260 nm) corresponds to the amount of dissolved organic matter, and the visible part (420 nm) corresponds to the amount of brown colored components. Since the ultraviolet part (260 nm) was measured by diluting twice, the actual absorbance is twice the displayed value.

  Here, in the case where a carbide carbonized at a carbonization temperature of 400 ° C. is used, an uncarbonized portion exists in the carbide, and the absorbance in the ultraviolet region increases. That is, the organic substance is eluted from the uncarbonized portion. On the other hand, it is determined that the carbonized carbonized at a carbonization temperature of 500 ° C. or higher is completely carbonized and adsorbs organic matter. Similarly, in the visible region, the coloration is slightly reduced at a carbonization temperature of 400 ° C., but at the carbonization temperature of 500 ° C. or more, the color is greatly reduced and the coloration is only slightly observed.

Thus, it became clear that the use of the carbide 12 carbonized at a carbonization temperature of 500 ° C. or higher can effectively adsorb organic substances and colored components in the agglomerated treated water. Table 2 shows an example of the result of the adsorption treatment performed in a contact time of 30 to 60 minutes in an actual adsorption tower packed with the carbide 12.

  From Table 2, it can be seen that COD (chemical oxygen demand), which has been difficult to treat in the past, was absorbed by the carbide 12 because the activated sludge treated water was 270 mg / l and the coagulated treated water was 170 mg / l. Since it decreases to 40 mg / l, it can be processed to a value lower than the drainage regulation value of 120 mg / l (daily average value). Similarly, the chromaticity value indicating the coloring component also decreases to 20 and clear treated water is obtained.

  As described above, conventionally, it has been difficult to perform treatment below the wastewater regulation value, but by using the carbide 12, it has become possible to perform treatment below the wastewater regulation value.

  The adsorbing treatment may be either upward flow or downward flow, but upward flow is preferable because a short path is less likely to occur. When the adsorption treatment is performed for a long time, the adsorption to the carbide 12 approaches saturation and eventually breaks through. The carbide which is the waste adsorbent 40 that has passed through is taken out from the adsorption tower of the adsorption treatment device 39, separated into solid and liquid by the solid-liquid separation device 8, and then carbonized again through dehydration and drying. Since the adsorbed coloring component and the hardly decomposable organic substance are gasified or carbonized in the carbonization furnace 9, the obtained carbide 12 can be reused. In this case, the solid-liquid separation device 8 is used for solid-liquid separation of the waste adsorbent 40 broken through by organic substance adsorption, and the separated solid content is dried by the drying device 37 and then supplied to the carbonization device 1 to be carbonized again. It also functions as a recycling facility for reusable playback.

  In general, when organic waste is carbonized by the carbonization apparatus 1, it has been clarified by tests that the manufacturing cost of the carbide 12 is several tenths of the purchase price of activated carbon. Therefore, by effectively using the carbide obtained from the waste, it becomes possible to reduce the drainage of the methane fermentation treatment liquid, which has been difficult to treat in the past, at a low cost or less.

  Moreover, since the methane fermentation apparatus 2 produces | generates methane fermentation gas by carrying out the methane fermentation process of the liquid waste 5 with the methane fermentation tank 15, the obtained methane fermentation gas 20 contains a lot of harmful hydrogen sulfide. Yes. For this reason, a desulfurization device 19 is provided to desulfurize the methane fermentation gas 20. Conventionally, iron oxide has been used as a desulfurizing agent, but there has been a problem in the disposal of the desulfurizing agent. That is, the desulfurization agent discharged from the desulfurization tower is ignited by contact with air. In addition, there is a problem that it is expensive to dispose as industrial waste.

  Therefore, the carbide 12 produced by the carbonization device 1 is used as the desulfurization agent of the desulfurization device 19. That is, the carbide 12 obtained by carbonizing at 500 ° C. or more in the carbonization apparatus 1 for about 15 to 60 minutes is used as a desulfurization agent for methane fermentation gas. When the carbide 12 is used as a desulfurization agent for the desulfurization unit 19, hydrogen sulfide is catalytically oxidized to sulfuric acid on the surface of the carbide and is effectively desulfurized.

  The waste desulfurization agent whose desulfurization treatment capacity has been reduced by long-term use is washed with water by the water washing device 42, and sulfuric acid adhering to the surface is washed away and recovered as a sulfuric acid-containing solution. The recovered sulfuric acid-containing solution is used as a pH adjusting agent for waste liquid treatment. On the other hand, the carbide that has become the waste desulfurizing agent 43 after washing is solid-liquid separated by the solid-liquid separator 8 and then carbonized again by the carbonizer 1 through the drying device 37. The surface and pores are regenerated by this recarbonization treatment and can be reused as carbide.

  That is, the methane fermentation apparatus 2 has a water washing apparatus 42 for washing the carbide whose desulfurization ability has been lowered by the desulfurization treatment to remove the produced and attached sulfuric acid, and the solid-liquid separation apparatus 8 is configured to remove the washed carbide in a solid-liquid form. The separated solid waste is supplied to the carbonization apparatus 1 to be carbonized again, and used as a waste desulfurization agent regeneration facility for reusability.

  In this way, desulfurization is performed with the carbide 12 obtained from the waste 4, and a solution containing sulfuric acid is recovered by washing with water, and can be reused by carbonization again. Therefore, the cost is low and no waste is generated. There is.

  Next, an example of the deodorizing process using the carbide 12 will be described. The carbide 12 obtained by the carbonization apparatus 1 is used as a deodorizer in the deodorization apparatus 44 to deodorize malodorous gas generated in the facility of the organic waste treatment system. FIG. 7 shows the adsorption characteristics of various gases by the carbide 12. The experiment was conducted using methyl mercaptan as the acid gas, ammonia as the basic gas, and acetaldehyde as the neutral gas. As a result, it became clear that the carbide 12 can adsorb any gas.

  Thus, since the carbide 12 can completely adsorb and remove many kinds of malodorous gases, it is possible to effectively deodorize mixed malodorous gases having a low concentration in a facility, which is difficult with a normal deodorizing method. That is, the deodorizing treatment can be performed by installing an adsorption tower near the low-concentration malodorous gas generation source or collecting the low-concentration malodorous gas through the duct.

  Since the carbide broken through by malodor gas adsorption contains a large amount of nitrogen, it can be used as the fertilizer 45. In particular, when phosphoric acid is added to the carbide 12 in a weight percent of about 2% or more, the ammonia adsorption amount is increased about 10 times compared to the case of no addition. The broken carbide can be used as the fertilizer 45 because it contains abundant phosphorus and nitrogen. Therefore, the deodorizing device 44 that adsorbs malodorous gas by the carbide 12 is also used as a fertilizer supply device that supplies the carbide broken through by adsorption as fertilizer.

  Next, the example which used the carbide | carbonized_material 12 for the fuel of the hot water boiler 46 which heats the methane fermentation tank 15 is demonstrated. As described above, the methane fermentation apparatus 2 uses the hot water 29 discharged from the fuel cell as the power generation apparatus 3 as a heating means for the methane fermentation tank 15, but a boiler 46 is provided to compensate for the shortage. ing. Therefore, the carbide 12 generated by the carbonizer 1 is used as fuel for the boiler 46 and burned.

  That is, when the power generation device 3 fails or when a sufficient amount of methane fermentation gas 20 cannot be obtained due to a trouble in the methane fermentation tank 15, the rated amount of hot water 29 cannot be obtained from the power generation apparatus 3, and the methane fermentation tank 15 The temperature of the lowers and fermentation decreases. In order to prevent this, a hot water boiler 46 is attached.

  Here, when the carbide 12 was analyzed, it was confirmed that it had a lower heating value of about 8000 kJ / kg. Therefore, the carbide 12 is supplied to the hot water boiler 46 as an alternative fuel for the fossil fuel and burned to obtain the hot water 29. That is, the carbide 12 obtained from the waste 4 can be used as a substitute for fossil fuel to obtain hot water with the boiler 46, and the fuel cost can be reduced.

  Next, an example will be described in which the carbide 12 is mixed with all or part of the waste liquid discharged from the methane fermenter 15 and used as it is as a fertilizer, or dried and fermented by sun drying and then used as a fertilizer. That is, a mixing device 47 for mixing the carbide 12 and the waste liquid discharged from the methane fermentation tank 15 is provided. The mixing weight ratio of the waste liquid and the carbide 12 in the mixing device 47 is 1 or more with respect to the waste liquid 1. When the total amount of the waste liquid is mixed with the carbide, the subsequent-stage waste liquid treatment device 16 is not necessary. When a part of the waste liquid is mixed with the carbide, the scale of the waste liquid treatment apparatus 16 at the subsequent stage can be reduced.

  Here, although the waste liquid after methane fermentation emits a considerable bad odor, mixing with the carbide 12 reduces the odor to the extent that there is no problem. In addition, it is also possible to spray the waste liquid after methane fermentation directly as liquid fertilizer to fields, fields, etc., but if it remains liquid fertilizer, the fertilizer components will not be absorbed and adsorbed sufficiently in the soil, but mixed into groundwater, Problems such as bad odor occur during spraying.

  On the other hand, as described above, by mixing with the carbide 12, the fertilizer component in the waste liquid is adsorbed by the carbide 12 or held in the pores, so that it gradually diffuses into the soil and the fertilizer component Is effectively used. There is no problem of bad odor. Therefore, the mixture of the carbide 12 and the waste liquid after methane fermentation is effective as a fertilizer.

  In addition, it cannot be overemphasized that the carbide | carbonized_material 12 obtained with the carbonization apparatus 1 of this system is applicable to general use as carbide | carbonized_materials, such as a soil improvement material, a snow melting material, and a humidity control material besides the above-mentioned each use.

  Next, an example of using dry distillation gas generated by carbonization will be described. The solid waste 7 introduced into the carbonization furnace 9 is carbonized to be obtained as a carbide 12 and a dry distillation gas 13 of 500 ° C. or higher. Since the dry distillation gas 13 contains a large amount of methane, hydrogen, carbon monoxide, and the like, it is converted into a high-temperature gas of 850 ° C. or higher when burned in the combustion furnace 10 and is used for heating the carbonization furnace 9. Excess dry distillation gas that has not been used for combustion in the combustion furnace 10 can be used as a fossil fuel substitute as the fuel for the hot water boiler 46 described above.

  The surplus dry distillation gas can also be preheated by exchanging heat with the desulfurized methane fermentation gas through a heat exchanger (not shown). In this case, the dry distillation gas itself is cooled. Further, since the dry distillation gas contains hydrogen sulfide and the like, as shown in the drawing, it can be mixed with methane fermentation gas in the previous stage of the desulfurization apparatus 41, desulfurized together, and used as a fuel for power generation. Thus, the thermal energy and combustion energy of the dry distillation gas can be used effectively.

  Next, the utilization example of the 200-500 degreeC carbonization furnace exhaust gas discharged | emitted after heating the carbonization furnace 9 is demonstrated. The carbonization furnace exhaust gas 14 is supplied to a heating pipe (not shown) provided in the methane fermentation tank 15, and after heating the methane fermentation tank 15, it is released into the atmosphere. Alternatively, it can be connected to a heating pipe of a hot water tank (not shown) attached to the hot water boiler 46 and used for heating the hot water tank. Both are alternatives to fossil fuels.

  Next, an example in which the carbonization furnace exhaust gas is used as a heat source for drying of the drying device 37 will be described. On the solid component outlet side of the solid-liquid separation device 8, a drying device 37 for drying the solid component separated into solid and liquid is provided. The carbonization furnace exhaust gas 14 is supplied to this drying device 37, and the solid-liquid separation device 8 is used to dry the solid separated into solid and liquid. As the drying device 37, for example, an indirect heating type rotary kiln is used, and the carbonization furnace exhaust gas 14 is introduced between an inner cylinder and an outer cylinder (not shown) to heat the inner cylinder. In this case, the solid content thrown into the inner cylinder is heated while being stirred in the inner cylinder, and the dried solid content is discharged from the inner cylinder outlet. On the other hand, the carbonization furnace exhaust gas 14 which heated the inner cylinder is discharged | emitted in air | atmosphere from an exhaust port.

  In such a drying device 37, fossil fuel has been conventionally used as a heat source, but by using the exhaust gas after heating the carbonization furnace 9 as a substitute for fossil fuel, consumption of fossil fuel can be reduced. .

  Next, the example which used the 200-500 degreeC exhaust gas discharged | emitted from a carbonization furnace for sludge concentration is demonstrated. Excess sludge 48 discharged from the activated sludge treatment of the waste liquid treatment device 16 is concentrated by gravity sedimentation in a sludge concentration tank (not shown) of the sludge concentration device 49. A heating pipe is provided at the bottom of the concentrating tank, and the carbonization furnace exhaust gas 14 is supplied through an introduction pipe connected to the heating pipe and warms sludge to about 30 to 50 ° C. When the sludge is heated, the viscosity of the liquid is lowered and the sedimentation property of the sludge is improved. For this reason, the concentration of the concentrated sludge increases, and there is an effect of facilitating subsequent solid-liquid separation. Thereby, the number of the solid-liquid separator 8 can be reduced, and a sludge concentration tank can be reduced in size.

  Next, an example of a deodorizing method for efficiently deodorizing high-concentration malodorous gas will be described. In organic waste treatment systems, high-concentration malodorous gases from liquid waste 5, solid-liquid mixed waste 6 storage tank, liquid waste stock tank, methane fermentation liquid receiving tank, solid-liquid separator after methane fermentation, etc. 50 is generated. These high-concentration malodorous gases 50 are sucked by a suction blower via a duct (not shown) and introduced into the combustion furnace 10 of the carbonization apparatus 1. For this reason, malodorous gas is used as a combustion air source. The malodorous component is reliably oxidatively decomposed at a high temperature of 850 ° C. or higher in the combustion furnace 10. After decomposition, it is discharged as carbonization furnace combustion gas 14. Accordingly, it is not necessary to separately install a deodorizing device for high-concentration malodorous gas, and efficient deodorization is possible.

  As described above, in the organic waste treatment system of the present invention, the methane fermentation apparatus, the carbonization apparatus, and, if necessary, the power generation apparatus utilize the respective characteristics and make up for each other, thereby taking into consideration the environment. Efficient treatment of organic waste becomes possible.

It is a conceptual diagram explaining one Embodiment of the organic waste processing system by this invention. It is a figure which shows the structural example of the carbonization apparatus used for one embodiment same as the above. It is a figure which shows the structural example of the methane fermentation apparatus used for one embodiment same as the above. It is a figure which shows the structural example of the electric power generating apparatus used for one embodiment same as the above. It is a figure explaining the specific system configuration | structure of one Embodiment same as the above. It is a graph which shows the adsorption | suction characteristic of the organic substance and coloring component by the carbide | carbonized_material in one Embodiment same as the above. It is a graph which shows the gas adsorption | suction characteristic by the carbide | carbonized_material in one Embodiment same as the above.

Explanation of symbols

1 Carbonization equipment 2 Methane fermentation equipment 3 Power generation equipment 4 Organic waste 5 Liquid waste (organic matter)
6 liquid mixture waste (organic)
7 Solid waste (organic matter)
8 Solid-liquid separator 9 Carbonization furnace 10 Combustion furnace 15 Methane fermentation tank 16 Waste liquid treatment device 19 Desulfurization device 37 Drying device 39 Adsorption device 44 Deodorization device 46 Boiler 47 Mixing device

Claims (16)

An organic waste treatment system divided into liquid organic matter, solid-liquid mixed organic matter, and solid organic matter,
A methane fermentation apparatus for producing methane fermentation gas by subjecting the liquid organic matter to methane fermentation, and supplying the generated methane fermentation gas as a fuel for power generation,
A carbonization device that heats and carbonizes the solid organic matter to produce carbide and dry distillation gas;
A solid-liquid separation device that separates the solid-liquid mixed organic material into a liquid organic material and a solid organic material, the liquid organic material is supplied to a methane fermentation device, and the solid organic material is supplied to a carbonization device;
An organic waste treatment system comprising:   The methane fermentation apparatus has a waste liquid treatment apparatus for waste liquid after methane fermentation, and in the adsorption treatment apparatus for organic matter in treated water separated from sludge by this waste liquid treatment apparatus, the carbide produced by the carbonization apparatus is used as an adsorbent. The organic waste treatment system according to claim 1, wherein the organic waste treatment system is used.   Solid-liquid separation equipment is used for solid-liquid separation of carbides broken through by adsorption of organic substances, and the separated solid waste is supplied to the carbonization equipment to be carbonized again and regenerated for reuse. The organic waste treatment system according to claim 2, wherein the organic waste treatment system is used as well.   The organic waste treatment system according to claim 2, wherein the carbide for adsorbing the organic matter is a carbide obtained by carbonization at a carbonization temperature of 500 ° C or higher.   The methane fermentation apparatus includes a desulfurization apparatus that desulfurizes the generated methane fermentation gas, and a carbide generated by the carbonization apparatus is used as a desulfurization agent of the desulfurization apparatus. Organic waste treatment system.   There is a water washing device that removes the sulfuric acid that has been deposited by washing the carbide whose desulfurization ability has been reduced by desulfurization treatment, and the solid-liquid separation device separates the solid waste that has been washed by solid-liquid separation. 6. The organic waste treatment system according to claim 5, wherein the organic waste treatment system is also used as a regeneration facility for a waste desulfurization agent that is supplied to a carbonization device, carbonized again, and is reusable.   The organic waste treatment system according to claim 1, wherein the carbide generated by the carbonization device is used as an adsorbent in a deodorization device for malodorous gas.   The organic waste treatment system according to claim 7, wherein the deodorization apparatus that adsorbs malodorous gas is also used as a fertilizer supply apparatus that supplies carbide broken through by adsorption as fertilizer.   2. The organic waste treatment system according to claim 1, wherein the methane fermentation apparatus has a boiler for heating the methane fermentation tank, and the carbide generated by the carbonization apparatus is used as fuel for the boiler.   The organic waste treatment system according to claim 1, further comprising a mixing device that mixes the carbide generated by the carbonization device and the waste liquid after methane fermentation in the methane fermentation device to generate fertilizer.   The carbonized gas obtained from the carbonization device is used as a heating fuel for a carbonization furnace constituting the carbonization device, mixed with a methane fermentation gas, and supplied as a fuel gas for power generation. Organic waste treatment system.   The carbonized gas obtained from the carbonization apparatus is used as a fuel for heating a carbonization furnace constituting the carbonization apparatus, and also used as a fuel for a boiler for heating a methane fermentation tank in the methane fermentation apparatus. Organic waste treatment system.   The organic waste treatment system according to claim 1, wherein the exhaust gas used for heating the carbonization furnace constituting the carbonization apparatus is used for heating the methane fermentation tank in the methane fermentation apparatus.   The solid-liquid separation device has a drying device for drying the solid content obtained by solid-liquid separation of the solid-liquid mixed organic matter, and the exhaust gas used for heating the carbonization furnace constituting the carbonization device is used as a heat source for the drying device. The organic waste treatment system according to claim 1, wherein the organic waste treatment system is used.   A waste liquid treatment apparatus for waste liquid after methane fermentation has a heating device for concentrated sludge generated by waste liquid treatment, and uses exhaust gas used for heating a carbonization furnace constituting the carbonization apparatus as a heat source for heating the concentrated sludge. The organic waste treatment system according to claim 1, wherein:   The carbonization apparatus has a combustion furnace for heating the carbonization furnace, sucks high-concentration malodorous gas generated from waste etc. with a suction blower via a duct, and introduces it into the combustion furnace as a combustion air source. The organic waste treatment system according to claim 1, wherein malodorous components are oxidatively decomposed by combustion heat.

Images