JP4067314B2 - Organic waste treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an organic waste processing apparatus for biofermenting organic waste such as garbage to produce biogas.
[0002]
[Prior art]
In recent years, the total amount of organic waste composed of raw garbage, livestock manure, sewage sludge and the like has been increasing year by year. And although the said organic waste etc. are composted and recycled, the quantity is very small and most are landfilled after incineration. However, raw garbage has a high moisture content, so it is easy to rot and difficult to burn alone, and it is difficult to raise the temperature in the furnace, which may cause generation of dioxins. There are concerns. In addition, the shortage of landfill sites and the difficulty of constructing incinerators are becoming social problems, and there is an urgent need for waste reduction and resource recycling.
[0003]
For this reason, for example, as shown in JP-A-9-174095, a magnesium salt is added to an organic slurry containing phosphoric acid and ammonium to form magnesium ammonium phosphate (MAP) crystals, The second step of separating the organic slurry containing MAP crystals into a solid phase and a liquid tank, the third step of aerobically fermenting the solid phase to produce compost containing MAP, and the liquid tank above The 4th process processed by the biofermentor of a counter current anaerobic sludge filter bed method, and the organic component and nitrogen in the effluent from the 4th process are removed by an aerobic biofilm processing tank and a denitrification tank. An organic slurry treatment method and treatment apparatus including five steps have been proposed, and biogas generated in the biofermentor is used as a fuel for a generator or a boiler. That.
[0004]
[Problems to be solved by the invention]
When it is configured to produce biogas containing methane gas by decomposing organic waste in anaerobic environment by fermenting action by methanogens that have formed flocs in the biofermentor as described above, While having the advantage of being able to effectively use biogas, the hydrogen sulfide generated in the biofermenter is likely to be mixed into the biogas and the generator or boiler is easily corroded by the hydrogen sulfide at an early stage. There was a problem.
[0005]
For this reason, in the organic slurry processing apparatus described in the above publication, hydrogen sulfide in the biogas generated in the biofermenter is absorbed into the effluent from the aerobic biofilm processing tank and desulfurized. A desulfurization tank is provided, and the liquid that has absorbed the sulfur compound in the desulfurization tank is supplied to the denitrification tank, and this liquid is used as an electron donor for the denitrification reaction, and the liquid after denitrification is supplied to the biofilm treatment tank. By returning, the residual hydrogen sulfide component is recovered as sulfur or sulfuric acid. However, even when the desulfurization tank is provided, it is difficult to completely remove hydrogen sulfide in the biogas, and this hydrogen sulfide is supplied to the generator or the boiler in a state where the hydrogen sulfide is mixed in the biogas. Therefore, there is a problem that they cannot be corroded.
[0006]
In addition, the organic slurry processing apparatus discharges liquid components generated in the process of generating compost, which is a solid component, and biogas containing methane gas, which is a gas component, as treated water, or as washing water for a livestock house Configured to use. However, since the liquid component contains a large amount of protein, ammonia component, and the like, there is a problem that environmental pollution such as eutrophication occurs when the liquid component is discharged.
[0007]
This invention is made | formed in view of said point, and provides the processing apparatus of the organic waste which can process the slurry containing an organic waste part appropriately, without producing environmental pollution etc. It is aimed.
[0008]
[Means for Solving the Problems]
The invention according to claim 1 is a biofermenter for producing biogas containing methane gas from a slurry containing organic waste by the fermentation action of methanogens, and supplying the air into the biofermentor to supply this biofermenter. By suppressing the activity of sulfate-reducing bacteria that live in the fermenter, the water introduction means for reducing the concentration of hydrogen sulfide in the biogas, and the water is separated from the suspension discharged from the biofermenter. A dehydrator, a purification means for decomposing and purifying the desorbed liquid discharged from the dehydrator, and a sterilizing section for producing liquid fertilizer by heating and sterilizing the purified liquid purified by the purification means, And a heat engine that uses biogas produced in the biofermentor as fuel, and is configured to supply exhaust gas discharged from the heat engine to the sterilization unit as a heat source for heating. It is intended.
[0009]
According to the above configuration, the organic waste is decomposed to produce biogas containing methane gas by the fermentation action of the methanogen living in the biofermentor, and air is introduced from the air introduction means. As a result, the activity of sulfate-reducing bacteria is suppressed, and the hydrogen sulfide concentration in the biogas is effectively reduced. In addition, the suspension discharged from the biofermentor is dehydrated by a dehydrator, purified by a purification means, and then heated using exhaust gas supplied from the heat engine as a heat source. A sterilized liquid manure is obtained and can be used effectively.
[0010]
The invention according to claim 2 is the organic waste treatment apparatus according to claim 1, wherein the cylindrical body extending in the vertical direction is disposed in the biofermentor and the biogas derived from the biofermenter Is provided with a stirring means for returning a part thereof to the cylindrical body and stirring.
[0011]
According to the above configuration, a part of the biogas derived from the biofermenter is returned to the cylindrical body and the inside thereof is stirred, so that the fermentation action of the methanogen is effectively promoted. It will be.
[0012]
The invention according to claim 3 is the organic waste treatment apparatus according to claim 1 or 2, wherein hot water circulating means for circulating hot water along the peripheral wall portion of the biofermentor and cold water along the peripheral wall portion are provided. A cold water circulation means for circulation and a temperature control means for controlling the temperature in the biofermentor by controlling the circulation state of the hot water and the cold water.
[0013]
According to the said structure, the production | generation of the biogas containing methane gas is effectively accelerated | stimulated by maintaining the inside of a biofermentor at the appropriate temperature which can promote the fermentation effect | action by a methane producer.
[0014]
The invention according to claim 4 is the organic waste treatment apparatus according to any one of claims 1 to 3, wherein the one or more metals selected from the group consisting of nickel, cobalt, iron and the like in the biofermentor are provided. An element is added.
[0015]
According to the said structure, the production | generation of the biogas containing the said methane gas is accelerated | stimulated more effectively by the effect | action of the metal enzyme which forms a complex with nickel ion, cobalt ion, or iron ion.
[0016]
The invention according to claim 5 is the organic waste treatment apparatus according to any one of claims 1 to 4, further comprising carbon dioxide removing means for removing carbon dioxide from the biogas produced in the biofermentor. It is a thing.
[0017]
According to the said structure, it becomes possible to raise the effectiveness by raising the methane gas concentration in the biogas produced | generated with the biofermentor effectively.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show an embodiment of an organic waste treatment apparatus according to the present invention. This organic waste treatment apparatus is a biofermenter 1 that produces biogas containing methane gas by the fermentation action of methanogens, and slurries organic wastes such as raw garbage and supplies them into the biofermenter 1 And a biogas treatment means 3 for treating the biogas derived from the biofermentor 1.
[0019]
The slurry supply means 2 includes a disposer 5 for subdividing by pulverizing organic waste such as garbage disposed via the conveyor 4, a storage pit 6 for storing the subdivided organic waste, The organic waste derived from the storage pit 6 is sprayed with fresh water supplied from the fresh water tank 7, and the organic waste is screened and a vibrating screen 9 for introducing a small-diameter body into the raw water pit 8. The pump 10 and the lead-out pipe 11 which lead out the slurry which consists of a mixture of the small diameter body of the organic waste introduced into 1 and the fresh water into the biofermentor 1 are provided. In addition, in order to eliminate the clogging of the vibration screen 9, the clean water is periodically sprayed on the vibration screen 9 so that the cleaning is performed.
[0020]
The biofermenter 1 has a cylindrical body 12 extending in the vertical direction at the center, a supply pipe 13 for supplying the slurry derived from the supply pipe 11 into the cylindrical body 12, and the biofermentor 1 Stirring means 14 is provided for returning a part of the biogas generated in the inside of the cylindrical body 12 and stirring the inside of the biofermenter 1, particularly the inside of the cylindrical body 12, and under anaerobic conditions. It contains methanogens that decompose organic matter to produce biogas containing methane gas.
[0021]
Then, the slurry is supplied from the outlet pipe 11 through the supply pipe 13 into the cylindrical body 12, and the cylindrical body 12 is supplied by the biogas supplied into the cylindrical body 12 through the stirring means 14. The organic waste in the slurry is decomposed by the fermenting action of the methanogenic bacteria propagated in the biofermenter 1 while the inside of the biofermenter 1 and the inside of the biofermenter 1 are agitated to produce biogas containing methane gas It has come to be.
[0022]
The biofermenter 1 is provided with an air introduction means 15 having an on-off valve for introducing air. The on-off valve of the air introduction means 15 is opened as necessary, and air is introduced into the biofermentor 1 within a range that does not adversely affect the fermentation action of the methanogen, so that It is configured to reduce the concentration of hydrogen sulfide mixed in the biogas by suppressing the activity of the sulfate-reducing bacteria that inhabit.
[0023]
The biogas treatment means 3 includes a desulfurization tank 16 that separates and desulfurizes a sulfur compound such as hydrogen sulfide remaining in the biogas derived from the biofermenter 1, and a dioxide dioxide mixed in the biogas after desulfurization. A carbon dioxide removing means 17 in which zeolite 13X and the like that adsorb and remove carbon components and silica gel having a dehydrating action are accommodated, and a gas holder 18 that stores the biogas that has passed through the carbon dioxide removing means 17 are provided. The biogas stored in the gas holder 18 is supplied as fuel for the heat engine 19 composed of a generator driving engine or a hot water boiler.
[0024]
In addition, as shown in FIG. 2, the biofermenter 1 sucks the slurry from the bottom of the biofermenter 1 and injects the slurry into the lower side, and the slurry above the biofermenter 1. A spray pipe 21 for spraying in a shower form and a lead-out pipe 23 for leading the suspension discharged from the bottom of the biofermenter 1 to the dehydrator 22 are provided. And while the inside of the biofermenter 1 is agitated by the slurry injected into the biofermenter 1 via the injection tube 20, the slurry applied to the upper part of the biofermenter 1 via the sprayer tube 21. As a result, the scum made of floating impurities is pushed to the side and discharged from the scum discharge port into the scum tank 24.
[0025]
The suspension discharged from the biofermenter 1 is led out to the dehydrator 22 through the lead-out pipe 23, and is separated into desorbed liquid and sludge by the dehydrator 22. The sludge is sterilized by being introduced into the agglomerator 25 together with the moisture adjusting material to be agglomerated and then heated in the primary fermentation unit 26 at a temperature of about 70 ° C. for about 4 days. In addition, after the primary fermentation treatment, the secondary fermentation portion 27 is subjected to secondary fermentation treatment for about 9 days to be composted.
[0026]
On the other hand, the desorbed liquid derived from the dehydrator 22 is introduced and stored in the raw water tank 28 and supplied to the purification means 32 having the anaerobic tank 29, the activated sludge tank 30, and the settling tank 31. After the desorbed liquid is decomposed and precipitated and filtered, a clarified liquid consisting of the supernatant is supplied to the sterilizing section 33 and heated at a temperature of about 140 ° C. or higher for about 15 minutes to be sterilized. Thus, the concentrated liquid fertilizer is configured to be generated. That is, the desorbed liquid contains various useful components represented by BOD (biochemical oxygen demand). By decomposing these useful components, a supernatant that can be used as liquid fertilizer is obtained. Will be generated.
[0027]
Further, exhaust gas discharged from the heat engine 19 using biogas as fuel is supplied to the sterilization unit 33 as a heat source for heating. The exhaust gas causes the sterilization unit 33 to have a predetermined temperature (about 140 ° C. or higher). ), The liquid fertilizer components supplied from the purification means 32 are sterilized.
[0028]
Further, as shown in FIG. 3, the peripheral wall of the biofermenter 1 has hot water circulation means having hot water circulation pipes 34 for circulating hot water derived from a water jacket or the like of the heat engine 19, tap water, etc. A cold water circulation means having a cold water circulation pipe 35 for circulating cold water made of
[0029]
And according to the detection signal of the temperature sensor 36 for detecting the temperature in the biofermenter 1, the actuator of the on-off valve 37 provided on the hot water circulation pipe 34 and the actuator of the on-off valve 38 provided on the cold water circulation pipe 35. Is provided with a temperature control means 39 for outputting an open / close command signal, and the control for maintaining the temperature in the biofermenter 1 at a temperature suitable for biofermentation is performed by controlling the circulation state of the hot water and cold water. It is configured. Experiments have confirmed that the temperature suitable for the biofermentation is about 53 ° C.
[0030]
In the processing apparatus of the organic waste which supplies the slurry containing organic waste in the biofermentor 1 as mentioned above, and produces | generates the biogas containing methane gas by the fermentation action of a methane producer, the said biofermenter 1 An air introduction means 15 for supplying air is provided therein, and the air introduction means 15 supplies air into the biofermenter 1 to suppress the activity of sulfate-reducing bacteria that live in the biofermenter 1. Therefore, the organic waste can be decomposed by the fermenting action of the methanogen in the biofermenter 1 to produce biogas containing methane gas, and the hydrogen sulfide concentration in the biogas can be effectively reduced. It can be reduced.
[0031]
Accordingly, the amount of the organic waste can be effectively reduced, and the biogas generated by decomposing the organic waste can be effectively used as a fuel for the heat engine 19 or the like. Furthermore, there is an advantage that the occurrence of a situation in which the heat engine 19 or the like using the biogas as a fuel is corroded due to the presence of hydrogen sulfide in the biogas can be effectively suppressed.
[0032]
And, as described above, a dehydrator 22 that separates water from the suspension discharged from the biofermenter 1, and a purification means 32 that decomposes and purifies the desorbed liquid separated by the dehydrator 22, A sterilization unit 33 that generates liquid fertilizer by heating and purifying the purified liquid purified by the purification means 32 and a heat engine 19 that uses biogas generated in the biofermentor 1 as fuel are provided. Since the exhaust gas discharged from the heat engine 19 is configured to be supplied to the sterilization unit 33 as a heat source for heating, the heat engine 19 is driven using the biogas generated in the biofermentor 1 as fuel. In addition, the liquid fertilizer can be effectively sterilized with a simple configuration, and bacteria or infectious protein particles (prions) in the liquid fertilizer can be extinct. Therefore, by producing liquid fertilizer sterilized from the effluent discharged from the biofermenter 1, its effective use can be achieved, and environmental pollution caused by the release of the effluent. Occurrence can be prevented.
[0033]
In particular, as shown in the above embodiment, after the sludge separated by the dehydrator 22 is introduced into the agglomerator 25 together with the moisture adjusting material and aggregated, in the primary fermentation unit 26 and the secondary fermentation unit 27 When it is configured to ferment and sterilize to produce compost, there is an advantage that it can be used effectively.
[0034]
Moreover, in the said embodiment, while arrange | positioning the cylindrical body 12 extended to an up-down direction in the biofermentor 1, some biogas derived | led-out from this biofermentor 1 is returned in the said cylindrical body 12. Since the agitation means 14 for agitation of the biofermentor 1 is provided, the agitation of the methanogen is effectively promoted by efficiently agitating the inside of the cylindrical body 12 with the biogas, thereby efficiently biogas. Can be generated.
[0035]
Furthermore, as shown in the said embodiment, the hot water circulation means which consists of the warm water circulation pipe 34 and the on-off valve 37 etc. which circulate warm water along the surrounding wall part of the biofermenter 1, and circulate cold water along the said surrounding wall part A chilled water circulation means comprising a chilled water circulation pipe 35 and an on-off valve 38 and the like, and a temperature control means 39 for controlling the temperature in the biofermentor 1 by controlling the circulation state of the hot water and the chilled water are provided. When the inside is maintained at an appropriate temperature (about 53 ° C.) so as to promote the fermentation action of the methanogen, biogas containing methane gas can be generated more effectively.
[0036]
Moreover, in the above embodiment, since the hot water derived from the water jacket or the like of the heat engine 19 using the biogas generated in the biofermenter 1 as a fuel is supplied to the hot water circulation pipe 34, There is an advantage that it is not necessary to provide special generation means for generation, and the entire configuration of the apparatus can be simplified.
[0037]
In addition, as shown in the above embodiment, when one or more metal elements selected from the group consisting of nickel, cobalt and iron are added to the biofermenter 1, nickel ions, cobalt ions or iron ions and complexes The production rate of the biogas can be greatly improved by the action of a metalloenzyme (Methyltransferase, Methylreductase, etc.) that forms.
[0038]
Further, as shown in the above embodiment, when the carbon dioxide removing means 17 in which the zeolite 13X and the like are accommodated is provided to remove carbon dioxide from the biogas generated in the biofermentor 1. Can increase the methane gas concentration in the biogas, and thus has an advantage of effectively improving its usefulness. In particular, when silica gel or the like having a dehydrating action is housed in the carbon dioxide removing means 17 together with the zeolite 13X or the like, the methane gas concentration in the biogas can be further effectively improved by removing the water in the biogas. Can be raised.
[0039]
【The invention's effect】
As described above, the present invention provides a biofermentor that produces biogas containing methane gas from a slurry containing organic waste by the fermentation action of methanogens, and supplies air into the biofermentor. By suppressing the activity of sulfate-reducing bacteria that live in the biofermentor, air introduction means for reducing the hydrogen sulfide concentration in the biogas and water from the suspension discharged from the biofermentor Dehydrator for separation, purification means for decomposing and purifying the effluent discharged from the dehydrator, and sterilization for producing liquid fertilizer by heating and sterilizing the purified liquid purified by the purification means And a heat engine that uses biogas generated in the biofermentor as fuel, and exhaust gas discharged from the heat engine is supplied to the sterilization unit as a heat source for heating. Since the organic waste is decomposed by the fermentation action of the methanogen in the biofermentor to produce biogas, the desulfurization action of the desulfurization bacteria effectively removes sulfur compounds from the biogas. To prevent the occurrence of corrosion of hot water boilers or generators that use biogas as a fuel due to the presence of sulfur compounds such as hydrogen sulfide and sulfuric acid in the biogas can do. Moreover, the heat engine can be driven by using the biogas generated in the biofermentor as fuel, and the liquid fertilizer can be effectively sterilized with a simple configuration, and its effective use can be achieved. There are advantages such as prevention of environmental pollution caused by the release of the desorbed liquid.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an embodiment of an organic waste treatment apparatus according to the present invention.
FIG. 2 is an explanatory diagram showing a processing unit of a residue generated by an organic waste processing apparatus.
FIG. 3 is an explanatory diagram showing a configuration of temperature control of a biofermentor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Biofermenter 12 Cylindrical body 14 Agitation means 15 Air introduction means 17 Carbon dioxide removal means 19 Heat engine 22 Dehydrator 32 Purification means 33 Sterilization part 34 Hot water circulation pipe (warm water circulation means)
35 Chilled water circulation pipe (Cooling water circulation means)

Claims (5)

Biofermenter that produces biogas containing methane gas from the slurry containing organic waste by the fermentation of methanogens, and sulfate reduction that feeds air into this biofermentor and inhabits this biofermenter Air suppression means for reducing the hydrogen sulfide concentration in the biogas by suppressing the fungal activity, a dehydrator for separating water from the suspension discharged from the biofermentor, and the dehydrator Purifying means for decomposing and purifying the discharged desorbed liquid, a sterilizing section for generating liquid fertilizer by heating and purifying the purified liquid purified by the purifying means, and generated in the biofermentor And an exhaust gas discharged from the heat engine as a heat source for heating to the sterilization unit. Wastes of the processing device. 2. The organic waste treatment apparatus according to claim 1, wherein a cylindrical body extending in the vertical direction is disposed in the biofermentor, and a part of the biogas derived from the biofermentor is disposed in the cylindrical body. An organic waste treatment apparatus comprising a stirring means for returning and stirring the inside of the bio tank. The organic waste treatment apparatus according to claim 1 or 2, wherein hot water circulating means for circulating hot water along the peripheral wall portion of the biofermentor, cold water circulating means for circulating cold water along the peripheral wall portion, and the hot water And a temperature control means for controlling the temperature in the biofermentor by controlling the circulation state of the cold water, and an organic waste processing apparatus. The organic waste treatment apparatus according to any one of claims 1 to 3, wherein one or more metal elements selected from the group consisting of nickel, cobalt, iron, and the like are added to the biofermentor. Organic waste treatment equipment. The organic waste processing apparatus according to any one of claims 1 to 4, further comprising carbon dioxide removing means for removing carbon dioxide from the biogas produced in the biofermentor. Processing equipment.

Images