JP2006223976A - Method for fermentation of organic waste and product using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for fermentation of organic waste such as high-water-content organic sludges to be treated, by which treatment is performed using no cut slips of paper or paper-made pallets that can result in higher cost. <P>SOLUTION: The method comprises dehydrating and drying organic waste such as organic sludges (e.g., dehydrated cakes, livestock feces, and garbage) to the water content of approximately 10%, mixing and agitating appropriate amounts of sludges resulting from papermaking, storing the mixture in a closed fermentation vessel that is capable of supplying air from the bottom and is provided with a predetermined insulation structure, so as to supply a large amount of air from the vessel bottom, and performing forced exhaust from the top of the vessel, thereby aerobically fermenting the mixture. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fermentation treatment method for organic waste such as organic sludge, and a solid material and a liquid material produced by the treatment method.

  Sludge and the like, which are organic wastes from various industries, have a water content of food organic sludge of 80% or more, but are rich in high proteins and carbohydrates. If fertilizer is obtained by fermentation treatment, waste is effectively used. Therefore, for the high moisture content which is a factor inhibiting fermentation, in the fermentation treatment of organic waste, conventionally, moisture adjusting materials such as rice straw, rice husk and sawdust are added, and the total moisture content is 55% to It was reduced to 60% and fermented for composting.

  However, the fermentation treatment with the addition of the moisture adjusting material is basically anaerobic fermentation, the fermentation temperature is low, and cannot be said to be an efficient treatment. In view of this, as means for fermenting organic sludge, means for aerobic fermentation by mixing paper strips in a disturbed state have been proposed (Patent Document 1: Japanese Patent Publication Nos. 7-91140 and 7-112958, 8-18892).

  The fermentation treatment adds about 5% weight ratio of paper slender cut to about 80-90% water-containing organic sludge, and secures a micro space in a disturbed state of the paper long cut, It expands the air contact area of sludge and enables aerobic fermentation. The specific means of fermentation is to perform a fermentation process using a so-called horizontal paddle fermenter in which a processing object stored in a pool-shaped open fermenter is supplied with air and stirred back with a stirring blade. However, depending on the difference in the object to be treated, it took 2-3 weeks to complete the fermentation.

  In addition, the sludge fermentation treatment using the above-mentioned long cut paper is relatively difficult in the case of sludge containing high lipids often found in food industry waste sludge. This is because it is a condition for high-speed fermentation that a free air flow path can be created in the sludge by mixing waste paper, but when the sludge has a high lipid content, the introduced cut waste paper absorbs fat and adheres to each other. However, as if a single layer of film was formed, free air flow was hindered, fermentation was remarkably delayed, and partly anaerobic fermentation. The same is also assumed when the waste paper mixed sludge has a high water content.

  In addition, when shifting from the sludge dehydration process (making cake) to the fermentation process, the paper shredded fragment used in the above-mentioned patent method is used in a disturbed state, and sludge is gradually added to the paper disturbing body. It is necessary to add a disturbing body of the shredded fragments to the agitating operation while adding or to the sludge that is continuously agitating, and the work at the start of the fermentation process is very complicated. That is, even if a piece of paper is simply mixed with dewatered sludge (sludge cake), the paper piece immediately becomes a water-absorbing state, does not form an air flow passage in the sludge, and does not undergo aerobic fermentation. In addition, paper strips are scattered quickly due to their light weight during disturbance work and sludge mixing work, causing problems such as adhesion and intrusion into various equipment. Fermentation automation (moisture adjustment agent input, transport to fermentation equipment) ) Had problems such as becoming an obstacle factor.

  Therefore, if paper pellets are used, it can be used for fermentation automation such as mixing into sludge, it is easy to adjust the water content, effective fermentation is also performed for high-fat sludge, and fermentation efficiency is also high. Knowing that it is good, adjust the moisture by mixing the moisture adjusting material in the form of paper pellets of 2-5mm diameter and 2-10mm length, and perform the aerobic fermentation while supplying predetermined air to the mixture The means to do was proposed (patent document 2: Unexamined-Japanese-Patent No. 2002-263622).

  As a pulp sludge treatment means, Patent Document 3 (Japanese Patent Publication No. 57-35153) discloses a mixed fermentation treatment means of pulp sludge and excess activated sludge. In the above treatment, the pulp sludge and surplus activated sludge are mixed so that the C / N ratio is 20 to 45 (the ratio of pulp sludge is about 85 to 75%), and the whole is dehydrated to 75% or less of moisture. It is made by aerobic fermentation of things.

Japanese Patent Publication No. 7-91140. JP 2002-263622 A Japanese Patent Publication No. 57-35153.

  In recent years, the demand for waste paper has increased, and the fermentation treatment of organic sludge using the above-mentioned slender cut waste paper has a problem in terms of cost. Similarly, adopting a paper pellet body also requires the cost of the paper pellet itself Therefore, a low-cost member that ensures aerobic conditions in fermentation treatment of organic sludge is demanded.

  Patent Document 3 discloses the mixing treatment of surplus activated sludge as a pulp sludge treatment means, but the main purpose is the treatment of pulp sludge, the amount of sludge to be treated is small, Pulp sludge, which is easy to dry and dewater, reduces the total water content of the mixture to 75% or less. Even if the mixing ratio is simply changed, organic sludge with a high water content (about 85%) cannot be treated efficiently. Not.

  Therefore, the present invention has found that dehydrated pulp sludge serves as a member that ensures aerobic conditions for organic sludge having a high water content, and proposes a novel means for treating organic sludge.

  In the organic waste fermentation treatment method according to the present invention, an appropriate amount of paper sludge dehydrated and dried to about 10% water is mixed and stirred in organic waste such as dehydrated cake of organic sludge, livestock dung, and garbage. The mixture is stored in a closed fermentation vessel that can be supplied with air from the bottom and has a predetermined heat insulation structure, and supplies a large amount of air from the bottom of the vessel and forcibly exhausts from above the vessel. And the mixture is aerobically fermented.

  By supplying air into the sealed container containing the mixture and forcibly exhausting, the entanglement of the fine fibers in the papermaking sludge containing a large amount of fine fibers constitutes an air passage and the air contact area of the dewatered cake As a result, air is easily scattered throughout the sludge, and a reliable aerobic fermentation is performed.

  Further, the fermented processed product using organic waste according to the present invention is characterized in that the fermented processed product produced by the fermentation method is formed by pressure molding and drying into a predetermined shape, In particular, the microfibers act to maintain a predetermined shape, and can be used as fertilizers having a desired shape such as a sheet shape or a pile shape, or seeds or cultivated soil can be mixed and seeded by direct spraying.

  Further, the liquid material according to the present invention is produced by condensing exhaust from the closed container in the fermentation treatment method, and contains sufficient fertilizing components by analysis, and can be used as liquid fertilizer or the like.

  As described above, the present invention is a method for fermenting organic waste, in which a high water content organic waste such as organic sludge is mixed with a dried product of paper sludge as a moisture adjusting material, and the mixture is subjected to aerobic fermentation. Yes, the papermaking sludge to be incinerated can be used effectively, and the fermented product produced by the fermentation method can be provided as a compost of a desired shape by being pressure-molded and dried into a predetermined shape. The liquid material obtained by dew condensation of water vapor that is sometimes generated can be used as liquid fertilizer or the like.

  Next, an embodiment of the fermentation method of the present invention will be described. The embodiment is carried out by storing the object to be processed in a sealed container, and the fermentation apparatus has an appropriate heat insulating structure (not a metal plate or a thin resin, as illustrated in FIG. A closed fermenter 1 having a structure such as a concrete structure in which internal heat is difficult to be released to the outside atmosphere), an inner lid 2 disposed in the fermenter 1, and the fermenter 1 The fermenter 1 is provided with an inner bottom portion 4 which is a double bottom with a large number of vent holes, and a blower blower 5 is provided in a space below the inner bottom portion 4. The exhaust blower 6 connected to the exhaust port and the exhaust port is attached to the lid 3, and a cooling unit (condensation device) 7, a steam / water separation unit (condensate water storage tank) 8, and a deodorization unit 9 are attached to the exhaust blower 6. They are provided sequentially.

  In the present invention, a paper sludge drying apparatus is required. The drying device is similar to a general drying device, and is designed to supply hot air from the bottom of the drying tank. The dewatered paper sludge is stored in the drying tank and the moisture is dried to around 10%. To do.

  200kg of paper sludge dried to about 10% of moisture with a drying device to organic sludge (each of food sludge with 800kg water content 80% water content and 800kg water content 80% sewage sludge) using the fermenter Is stored in a 1-ton fermentation vessel 1 having a width of 1.2 m, a depth of 1.7 m, and a height of 1.35 m, 160 L of normal temperature air is fed into the fermenter 1 with the blower blower 5 and exhausted. The blower was forcibly exhausted with a rated output of 200 L / min.

  In order to confirm the fermentation state of the mixed sludge by continuously supplying and exhausting the temperature, the temperature sensor 10 is arranged at 15 cm, 45 cm, and 75 cm from the bottom of the fermenter 1, and the measurement results are shown in FIGS. It is as follows.

  In the case of food sludge treatment, it can be confirmed from the measurement results that fermentation has progressed from above, the peak at the bottom part is on the eighth day, and the entire temperature has fallen from the 10th day onward, thus ending the fermentation. . In the case of sewage sludge, the upper and lower fermentation progress states are different, but the fermentation is completed in about 10 days.

  The inner lid 2 protects the processing object from the heat retention effect of the processing object against the volume reduction of the processing object due to moisture evaporation and the condensation in the upper space inside the fermenter 1 caused by the volume reduction of the processing object. Has the effect of

  The fermented product contains 60 to 70% of moisture, and when this is further dried to about 20% with a dryer and granulated at a pressure of 280 kg / square cm, it becomes solid fertilizer. When this solid fertilizer was used for cultivation of Japanese mustard spinach, a sufficient fertilizer effect could be confirmed.

  Of course, the fermented product is granulated, used as a plate-shaped solid fertilizer, mixed with seeds during pressure molding of the plate-shaped solid fertilizer to form a seed-containing fertilizer plate, or a rod-shaped body By forming it into a fertilizer and inserting it around the cultivated plant in the field, a desired fertilization is possible. In addition, it is possible to form in various shapes corresponding to a desired usage pattern.

  The exhaust from the fermenter 1 passes through a cooling unit (condensation device) 7 to condense water vapor during fermentation, and the condensed water is stored in a steam / water separation unit (condensate water storage tank) 8. This condensed water contains a fertilizer component as illustrated in FIG. 4 and can also be used as liquid fertilizer.

Explanatory drawing of the implementation apparatus of this invention method. Temperature course table showing the fermentation state of the mixed sludge (food sludge and paper sludge). The temperature course which shows the fermentation state of the mixed sludge (sewage sludge and papermaking sludge). Component analysis table of the condensed water.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fermenter 2 Middle cover body 3 Sealing cover body 4 Inner bottom part 5 Blower blower 6 Exhaust blower 7 Cooling part (condensing device)
8 Air / water separation unit (condensate storage tank)
9 Deodorizing part 10 Temperature sensor

Claims (7)

  Organic sludge dehydrated cake, livestock excrement, raw garbage, and other organic waste can be mixed and stirred in an appropriate amount of paper sludge dehydrated and dried to a moisture content of about 10%. The mixture can be supplied with air from the bottom. In addition, it is housed in a closed fermentation vessel having a predetermined heat insulation structure, and a large amount of air is supplied from the bottom of the vessel, and forced exhaust is performed from above the vessel, and the mixture is subjected to aerobic fermentation. A method for fermenting organic waste.   2. The method for fermenting organic waste according to claim 1, wherein 10 to 20% of the amount of organic sludge is mixed and stirred to form a mixture to be fermented.   The organic waste according to claim 1 or 2, wherein forced exhausting is performed with a suction device that has a capacity higher than that of a blower that pushes the supply air, and an aerobic fermentation process is performed with the inside of the closed fermentation vessel being in a negative pressure state. Fermentation processing method.   The method for fermenting organic waste according to claim 1, wherein the processing object stored in the container is covered with a heat retaining inner lid.    A fermented processed product using the fermented processed product produced by the fermentation processing method according to any one of claims 1 to 4 as a solid fertilizer by pressure molding and drying into a predetermined shape.    The fermented material produced by the fermenting method according to any one of claims 1 to 4 is added with a fertilizer component diluent such as pulverized and refined paper, wood, and inorganic material, followed by pressure molding and drying. Fermented processed product use.   5. The fermentation material processing method according to claim 1, wherein the liquid material is produced by condensing exhaust from the sealed container.

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