WO2011013491A1

WO2011013491A1 - Method for treatment of sludge, and facility for the treatment

Info

Publication number: WO2011013491A1
Application number: PCT/JP2010/061545
Authority: WO
Inventors: 弘荒木
Original assignee: Araki Hiroshi
Priority date: 2009-07-29
Filing date: 2010-07-07
Publication date: 2011-02-03
Also published as: JP2011031119A

Abstract

Disclosed are a method for treating a sludge containing a fibrous organic material and a facility (10) for the treatment. The method comprises a dehydration step and a granulation step. In the dehydration step, a part of water is removed from a sludge that has been produced in a sewage or livestock excreta treatment plant (11) and contains a fibrous organic material, thereby producing a water-reduced sludge in which the fibrous organic material is aggregated and the water content is reduced to 40 to 75 mass% inclusive. In the granulation step, the water-reduced sludge is mixed with calcined lime to cause the reaction between water contained in the water-reduced sludge with calcined lime, thereby producing hydrated lime. At the same time, the surface tension of water contained in the water-reduced sludge is released while heating the water-reduced sludge with heat generated in the hydrated lime production reaction, so that the fibrous organic material is dispersed in the water-reduced sludge and a part of hydrated lime is adhered on the surface of the dispersed organic material that has been shrunk and rounded, thereby producing granules of which surfaces are coated with hydrated lime. Hydrogen sulfide that is generated in the course of the decomposition of the organic material in the granules produced in the granulation step is reacted with hydrated lime that covers the organic material, thereby converting hydrogen sulfide into calcium sulfide.

Description

Sludge treatment method and treatment equipment

The present invention relates to a method for treating sludge generated at a sewage or livestock manure treatment plant and a treatment facility therefor.

In sewage treatment plants, a large amount of sludge is generated due to sewage treatment, and some of it may be used as fertilizer, but most of the sludge is dehydrated to reduce water sludge (dehydrated cake) and directly or incinerated. The landfill is later disposed (see, for example, Patent Document 1).
Here, the water-reduced sludge is sponge-like containing 65 to 75% by mass of water, and about 90% by mass or more of the solid content is a fibrous organic substance derived from food having a length of 2 to 10 mm, and the balance is inorganic. It has become.

Japanese Patent Laid-Open No. 3-207497

However, in the invention described in Patent Document 1, since the essential treatment of water-reduced sludge (treatment of fibrous organic matter) is not performed, if the water-reduced sludge is left untreated, it is generated during decomposition of the organic matter. There is a problem that bad odor is generated due to hydrogen sulfide. The generated hydrogen sulfide reacts with oxygen in the air to turn into sulfurous acid gas, and the sulfurous acid gas further dissolves in water to become sulfuric acid. Therefore, the sludge treatment work is environmentally, hygienically and in equipment maintenance. It has become a very problematic task.

The present invention has been made in view of such circumstances, and can be effectively used by treating the reduced water sludge while preventing the release of hydrogen sulfide generated from the reduced water sludge formed by dewatering the sludge containing fibrous organic matter. An object of the present invention is to provide a sludge treatment method and treatment equipment for making a sludge treatment product.

The sludge treatment method according to the first invention that meets the above-mentioned object is a method of dewatering a part of water from sludge containing fibrous organic matter derived from food that is generated at a sewage or livestock manure treatment plant, A dehydration step for producing reduced water sludge having a water content of 40% by mass or more and 75% by mass or less by agglomerating organic substances in the form of water;
Quick lime is added to and mixed with the reduced water sludge, slaked lime is generated by the reaction of the moisture in the reduced water sludge and the quick lime, and the reduced water sludge is heated while heating the reduced sludge with heat generated by the reaction of generating the slaked lime. The surface tension of the moisture in the inside is released to disperse the fibrous organic matter, and a part of the slaked lime is attached to the surface where the dispersed organic matter is shrunk and rounded, and the surface is coated with the slaked lime. A granulating step for producing a product,
Hydrogen sulfide generated in the process of decomposing organic matter in the granulated product produced in the granulating step is reacted with the slaked lime covering the organic matter to change to calcium sulfide.

Here, in the dehydration step, the moisture content of the sludge is adjusted to a range of 40% by mass or more and 75% by mass or less, and the fibrous organic matter contained in the sludge is aggregated using the surface tension of water, and the sponge Can be formed, and the sludge can be handled easily. If the water content of the sludge is less than 40% by mass, the distance between the fibrous organic substances dispersed in the free water becomes small and becomes easily entangled with each other, and the size of the granular material generated in the granulating step becomes too large ( For example, exceeding 20 mm is not preferable because a crushing treatment is required. On the other hand, when the moisture content of the sludge exceeds 75% by mass, the distance between the fibrous organic substances dispersed in the free water is not increased and entangled with each other, and the size of the granular material generated in the granulating step becomes too small. (For example, less than 1 mm), it is easy to generate dust, which is not preferable.

In the sludge treatment method according to the first invention, it is preferable to adjust the size of the particulate matter by changing the water content of the reduced water sludge.

In the sludge treatment method according to the first invention, a drying step of adjusting the moisture content in the granular material by further heating the granular material produced in the granulating step at a temperature of 100 ° C. or higher and 150 ° C. or lower. It is preferable to have.

Here, the temperature at the time of heating shall be 100 degreeC or more and 150 degrees C or less, and a granular material can be sterilized and the safety | security of a granular material can be improved. In addition, when the temperature at the time of heating is less than 100 degreeC, since the time which adjustment of a moisture content requires becomes long, an efficient process cannot be performed and the effect of sterilization is small, it is not preferable. On the other hand, when the temperature at the time of heating exceeds 150 ° C., the drying proceeds excessively, and the produced granular material is likely to be pulverized (collapsed), which is not preferable.

In the sludge treatment method according to the first aspect of the present invention, a firing step in which the particulate matter produced in the granulation step is fired and the organic matter in the particulate matter is burned to disappear.
Adding and mixing moisture and quicklime to the incinerated ash obtained in the firing step, producing a first mixture in which the incinerated ash is dispersed in slaked lime generated by the reaction between the quicklime and the moisture;
Magnesium hydroxide produced by further adding light-burned magnesia to the first mixture obtained in the manufacturing process of the first mixture and mixing, and reacting the light-burned magnesia with moisture in the first mixture. In the first mixture to produce a second mixture that gradually solidifies while producing a hydrate by reaction of the slaked lime in the first mixture with the magnesium hydroxide. Have
Before the second mixture is solidified, it is preferable to mold the second mixture to solidify the second mixture into a specific shape.

The sludge treatment facility according to the second aspect of the invention that meets the above-mentioned object is generated in a sewage or livestock manure treatment plant, and a part of moisture is dehydrated from sludge containing fibrous organic matter derived from food. A reduced water sludge production apparatus for producing reduced water sludge having a water content of 40% by mass or more and 75% by mass or less.
Quick lime storage means for storing quick lime used for the treatment of the sludge;
A first stirring and mixing device,
In the first stirring and mixing device, the reduced water sludge from the reduced water sludge production device and quick lime supplied from the quick lime storage means are received and mixed, and slaked lime is formed by a reaction between the moisture in the reduced water sludge and the quick lime. While heating the water-reduced sludge with the heat generated by the reaction of forming the slaked lime, the surface tension of water in the water-reduced sludge is released to disperse the fibrous organic matter, and the dispersed organic matter is shrunk. Part of the slaked lime is adhered to the rounded surface to produce a granular material whose surface is coated with the slaked lime.

Here, the water content of the sludge is adjusted to a range of 40% by mass or more and 75% by mass or less by using the reduced water sludge production apparatus, and the fibrous organic matter contained in the sludge is aggregated using the surface tension of water. Thus, a sponge-like water-reduced sludge can be formed, and the sludge can be easily handled. If the moisture content of the sludge is less than 40% by mass, the distance between the fibrous organic substances dispersed in the free water becomes small and becomes easily entangled with each other, and the size of the granular material produced by the first stirring and mixing apparatus increases. Too much (for example, more than 20 mm), a crushing process is required, which is not preferable. On the other hand, when the moisture content of the sludge exceeds 75% by mass, the distance between the fibrous organic substances dispersed in the free water is not increased and entangled with each other, and the size of the granular material generated by the first stirring and mixing apparatus is It is not preferable because it becomes too small (for example, less than 1 mm) and is likely to generate dust.

The sludge treatment facility according to the second invention further includes drying means for reducing the water by heating the granular material produced by the first stirring and mixing device at a temperature of 100 ° C. or higher and 150 ° C. or lower. It is preferable.

Here, by heating the granular material to 100 ° C. or higher and 150 ° C. or lower using a drying means, the granular material can be sterilized and the safety of the granular material can be enhanced. In addition, when the heating temperature of a granular material is less than 100 degreeC, since the time required for water reduction of water becomes long, an efficient process cannot be performed and the effect of sterilization is small, it is not preferable. On the other hand, if the heating temperature of the granular material by the drying means is 150 ° C. or higher, the drying proceeds too much, and the produced granular material tends to be pulverized (collapsed), which is not preferable.

In the sludge treatment facility according to the second invention, further, a firing furnace for producing incinerated ash by firing the granular material produced by the first stirring and mixing device at a temperature of 800 ° C. or more and 1200 ° C. or less;
Light-burning magnesia storage means for storing light-burning magnesia used for the treatment of the incineration ash,
The incinerated ash from the calcining furnace, the quick lime from the quick lime storage means, and water are mixed to produce a first mixture, and the light burned magnesia received from the light burned magnesia storage means is added to the first mixture. A second stirring and mixing device for mixing to produce a second mixture;
Molding means for shaping the second mixture and solidifying the second mixture into a specific shape before the second mixture produced by the second stirring and mixing device solidifies;
The first mixture is produced by dispersing the incinerated ash in slaked lime generated by the reaction of the mixed quicklime and moisture, and the second mixture is the light burned magnesia and the first mixture. Magnesium hydroxide produced by reaction with moisture in the first mixture is produced by being dispersed in the first mixture, and the second mixture is a mixture of the slaked lime and the magnesium hydroxide in the first mixture. It is preferable to gradually solidify while producing a hydrate by the reaction.

Here, by firing the granular material at a temperature of 800 ° C. or higher and 1200 ° C. or lower, the organic matter in the granular material can be burned, and the slaked lime in the granular material can be converted into quick lime. As a result, incineration ash can be generated to reduce the volume, and the amount of quicklime added when the first mixture is produced can be reduced. In addition, if the temperature at the time of baking a granular material is less than 800 degreeC, while burning an organic substance and producing | generating incineration ash and aiming at volume reduction, it will become difficult to make slaked lime in a granular material completely quick lime. It is not preferable. On the other hand, even if the temperature at which the granular material is calcined exceeds 1200 ° C., the amount of incinerated ash to be produced and the amount of quicklime are not changed, and the calcining cost increases.

In the sludge treatment facility according to the second aspect of the invention, the second stirring and mixing device can be used as the first stirring and mixing device.

In the sludge treatment method according to the first invention and the sludge treatment facility according to the second invention, since the periphery of the organic matter in the particulate matter is coated with slaked lime, hydrogen sulfide generated during the decomposition of the organic matter ( The main cause of bad odor) can be prevented, and the generated hydrogen sulfide reacts with slaked lime and is consumed in the formation of calcium sulfide. Therefore, the generation of bad odor is ensured until the decomposition of organic matter is completed. Can be prevented. This prevents the release of hydrogen sulfide generated during the treatment of sludge into the atmosphere, and no sulfurous acid gas is generated in the sewage or livestock excreta treatment plant, thereby preventing the generation of sulfuric acid. As a result, environmental, hygienic and facility maintenance problems during sludge treatment can be solved.
And since sludge is heated using the reaction heat generated at the time of slaked lime generation during the treatment, it is possible to sterilize pathogens in the sludge, kill parasites and seeds, and handle the sludge after treatment. Safety can be ensured. Moreover, since the sludge after a process is a granular material, handling of sludge becomes easy. In addition, the calcium sulfide covering the particulate matter is gently hydrolyzed in the presence of moisture to be changed into calcium hydrogen sulfide and calcium hydroxide, so that generation of malodor can be prevented even when the calcium sulfide is decomposed. Furthermore, the generated calcium sulfide absorbs moisture and carbon dioxide in moist air to generate hydrogen sulfide, but the reaction rate when calcium sulfide generates moisture and moisture to absorb hydrogen sulfide is considerably high. Because it is slow, it does not substantially react in air at room temperature. Therefore, the granular material whose surface is coated with calcium sulfide exists stably in the atmosphere. For this reason, it is possible to transport and store the granular material in the atmosphere without any trouble.

In the sludge treatment method according to the first invention, when adjusting the size of the particulate matter by changing the water content of the reduced sludge, it is possible to obtain a particulate matter having the optimum size for the final disposal, and the efficiency of the final disposal. Can be achieved.

In the sludge treatment method according to the first aspect of the invention, when the granule produced in the granulation step is heated at a temperature of 100 ° C. or higher and 150 ° C. or lower to adjust the amount of moisture in the granule, The product can be sterilized and the moisture can be adjusted, and the granular material can be used as a safe and high quality organic fertilizer.

In the sludge treatment method according to the first invention, the granule produced in the granulation step is baked to burn the organic matter in the granule and disappear, and the incinerated ash obtained in the calcination step contains moisture. And the first mixture obtained by the step of manufacturing the first mixture in which the incinerated ash is dispersed in the slaked lime generated by the reaction between the quicklime and moisture, and the first mixture. Further, lightly burned magnesia is added to and mixed, and magnesium hydroxide produced by the reaction of lightly burned magnesia and the water in the first mixture is dispersed in the first mixture, and slaked lime in the first mixture is dispersed. Producing a second mixture that gradually solidifies while forming a hydrate by reaction with magnesium hydroxide, and forming the second mixture before solidifying the second mixture. When solidifying the mixture of 2 into a specific shape The second mixture may be produced building materials, for example roadbed material or the like.

In the sludge treatment facility according to the second aspect of the invention, when further comprising drying means for reducing the water by heating the granular material produced by the first stirring and mixing device at a temperature of 100 ° C. or more and 150 ° C. or less, The sterilization and moisture adjustment of the granular material can be performed, and the granular material can be used as an organic fertilizer with high safety and quality.

In the sludge treatment facility according to the second invention, further, a firing furnace for producing incinerated ash by firing the granular material produced by the first stirring and mixing apparatus at a temperature of 800 ° C. or higher and 1200 ° C. or lower, and incinerated ash A first mixture is produced by mixing light-burned magnesia storage means for storing the light-burned magnesia used in the treatment of the incineration ash from the baking furnace, quick lime from the quick lime storage means, and moisture. Before the solidification of the second mixture produced by the second agitating and mixing apparatus, and the second mixture produced by the second agitating and mixing apparatus. When the second mixture is formed and the forming means for solidifying the second mixture into a specific shape is included, construction materials such as roadbed materials can be produced from the second mixture.

In the sludge treatment facility according to the second invention, when the second stirring and mixing device is also used as the first stirring and mixing device, the equipment constituting the sludge treatment facility can be reduced, and the sludge treatment facility can be made compact and inexpensive. Can be configured.

It is a block diagram explaining the processing equipment of sludge concerning one example of the present invention. It is explanatory drawing of the processing method of the sludge which concerns on the 1st Example of this invention. It is explanatory drawing of the processing method of the sludge which concerns on the 2nd Example of this invention.

Subsequently, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
As shown in FIG. 1, a sludge treatment facility 10 according to an embodiment of the present invention is generated at a sewage or livestock manure treatment plant 11 and a part of moisture from sludge containing fibrous organic matter derived from food. Water-reducing sludge production apparatus 12 for producing water-reduced sludge having a water content of 40% by mass to 75% by mass, and quick lime storing means for storing quick lime used for sludge treatment 13 and a first stirring and mixing device 14 for receiving and mixing quicklime supplied from the reduced water sludge and quicklime storage means 13. This will be described in detail below.

Here, the reduced water sludge production apparatus 12 includes a transport pipe 16 including a pump 15 which is an example of a transport means for transporting the sludge discharged from the treatment plant 11. Further, the water-reducing sludge production apparatus 12 communicates with the downstream side of the transport pipe 16, receives the transported sludge, removes a part of the water, and has a predetermined water content, for example, a moisture content of 40% by mass or more 75. A filter press 17 which is an example of a dewatering means for producing reduced water sludge having a mass% or less range, and a belt conveyor which is an example of a conveying means for conveying the reduced water sludge produced by the filter press 17 to the first stirring and mixing device 14. 18.

Thereby, the sludge generated in the treatment plant 11 can be recovered, and the reduced water sludge containing a predetermined amount of water can be manufactured by adjusting the pressure applied by the filter press 17, for example. Can be supplied to the process. Instead of the filter press 17, a centrifuge that separates moisture using a centrifugal force can also be used.

Moreover, in the 1st stirring and mixing apparatus 14, the quick lime and the water | moisture content in a reduced water sludge are made to react by accepting and mixing the reduced water sludge supplied from the belt conveyor 18, and the quick lime supplied from the quick lime storage means 13. While generating slaked lime and heating the reduced water sludge with the heat generated by the slaked lime generation reaction, the basicity of the water in the reduced water sludge is increased to release the surface tension of the water in the reduced water sludge and Organic matter is dispersed. Next, in the first stirring and mixing device 14, slaked lime is attached to the surface where the dispersed organic matter is shrunk and rounded to produce a granular material whose surface is coated with slaked lime. And the granular material manufactured with the 1st stirring and mixing apparatus 14 is taken out outside using the belt conveyor 20 which is an example of the conveying means with which the 1st stirring and mixing apparatus 14 was equipped.

Here, the quick lime storage means 13 communicates with the quick lime storage hopper 21 for storing quick lime powder, and the quick lime storage hopper 21, and discharges a fixed weight of quick lime powder from the quick lime storage hopper 21. And a cutting machine 22. Further, the quicklime storage means 13 has a quicklime transport pipe 23 in which the discharge port of the quicklime excavator 22 and the base side communicate with each other and the front side communicates with the first stirring and mixing device 14.

In addition, the sludge treatment facility 10 includes a dryer 24 that is an example of a drying unit that receives the granular material conveyed via the belt conveyor 20 and heats it at a temperature of 100 ° C. or higher and 150 ° C. or lower to reduce water. Yes. Here, as the dryer 24, one having a function of adjusting the moisture content of the granular material to 5 to 10% by mass can be used. For example, the granular material is accommodated and placed in a heated air stream. Then, the type of drying can be used.

Further, the sludge treatment facility 10 is used for the firing furnace 25 for producing the incinerated ash by calcining the granular material produced by the first stirring and mixing device 14 at a temperature of 800 ° C. or more and 1200 ° C. or less, and for treating the incineration ash. A first mixture is produced by mixing the light-burned magnesia storage means 26 for storing the light-burning magnesia to be used, the incinerated ash from the baking furnace 25, the quick lime from the quick lime storage means 13, and moisture, to produce a first mixture. Before the solidification of the second mixture produced by the second agitating and mixing apparatus and the second agitating and mixing apparatus for producing the second mixture by mixing the lightly burned magnesia received from the lightly burned magnesia storage means 26 And a press molding machine 30 which is an example of molding means for forming the second mixture and solidifying the second mixture into a specific shape, for example, a shape suitable for a roadbed material.
In this embodiment, since the first stirring and mixing device 14 also serves as the second stirring and mixing device, the incinerated ash produced in the baking furnace 25 is sent again to the first stirring and mixing device 14. Incineration ash, quicklime, and moisture are mixed in the first stirring and mixing device 14 to produce a first mixture, and further, a light mixture of magnesia is mixed with the first mixture to produce a second mixture. become.

Here, an incinerator conventionally used for sludge treatment can be used as the firing furnace 25. The light-burning magnesia storage means 26 communicates with the light-burning magnesia storage hopper 27 for storing the light-burning magnesia powder, and the discharge port provided at the lower part of the light-burning magnesia storage hopper 27. A light-burned magnesia extractor 28 for discharging a light-weight magnesia powder of a constant weight, a light-burned magnesia transport pipe in which the discharge port of the light-burned magnesia extractor 28 and the base side communicate with each other and the front side communicates with the first stirring and mixing device 14 29.

By setting it as such a structure, incineration ash is disperse | distributed in the slaked lime produced | generated by reaction with quick lime and water | moisture content by stirring and mixing incineration ash, quick lime, and a water | moisture content with the 1st stirring mixing apparatus 14 first. A first mixture can be produced. Next, the first stirring and mixing device 14 stirs and mixes light-burned magnesia into the first mixture, so that the magnesium hydroxide produced by the reaction between the light-burning magnesia and the moisture in the first mixture becomes the first. A second mixture that is dispersed in the mixture and gradually solidifies while producing a hydrate by reaction of slaked lime and magnesium hydroxide in the first mixture can be produced. And before a 2nd mixture solidifies, the 2nd mixture can be shape | molded into the shape of a roadbed material using the press molding machine 30, and can be solidified. Instead of the press molding machine 30, an extrusion molding machine can be used.

Next, the sludge treatment method according to the first embodiment of the present invention will be described.
As shown in FIG. 2, the method for treating sludge according to the first embodiment is a method for producing organic fertilizer from sludge that is generated at a sewage or livestock manure treatment plant 11 and contains fibrous organic matter derived from food. And it has the dehydration process which dehydrates a part of water | moisture content from sludge, and manufactures the reduced water sludge whose fibrous organic substance aggregates and a moisture content is 40 to 75 mass%. Furthermore, the sludge treatment method receives the produced reduced water sludge in the first stirring and mixing device 14, adds and mixes the quick lime supplied from the quick lime storage means 13, and reacts the water in the reduced water sludge with quick lime. While generating the slaked lime and heating the reduced water sludge with the heat generated by the slaked lime generation reaction, the surface tension of the water in the reduced sludge is released to disperse the fibrous organic matter in the moisture contained in the reduced water sludge. A granulated step of producing a granular material by covering the surface of the dispersed organic material which has shrunk and rounded with a portion of slaked lime, and heating the produced granular material at a temperature of 100 ° C. to 150 ° C. And a drying step for adjusting the amount of water. Hereinafter, description will be made sequentially.

(Dehydration process)
When sludge containing fibrous organic matter is reduced using a filter press 17 so that the water content is in the range of 40% by mass or more and 75% by mass or less, the fibrous organic matter is aggregated by the surface tension of moisture, and becomes sponge-like. Less water sludge. Here, by changing the pressure applied by the filter press 17, the water content can be adjusted, and the organic content in the reduced water sludge can also be adjusted. The length of the fibrous organic material is, for example, 2 to 10 mm.

(Granulation process)
When the reduced water sludge is supplied to the first stirring and mixing device 14 and further the quick lime supplied from the quick lime storage means 13 is added and mixed, between the moisture in the reduced water sludge and the quick lime,
CaO + H ₂ O → Ca (OH) ₂
The slaked lime (Ca (OH) ₂ ) is generated. As a result, the basicity of the water in the reduced sludge increases, the surface tension of the water in the reduced sludge is released, and the fibrous organic matter that has aggregated due to the surface tension is released from the agglomerated state. The contained water becomes free water. For this reason, the released fibrous organic matter is dispersed in free water. The fibrous organic matter dispersed in the free water is shrunk and rounded (spheroidized) to form a round product. A part of the slaked lime adheres to the surface of the round product, and the surface is made of slaked lime. A coated granulate is formed. The weight of quicklime added is 0.2 to 0.6 when expressed as a weight ratio to the weight of the reduced sludge having a moisture content of 75 mass%. Here, when the weight ratio is less than 0.2, since the reaction heat of the generated slaked lime is small, it becomes clayy due to excess moisture. On the other hand, if the weight ratio exceeds 0.6, the reaction heat of the generated slaked lime becomes excessive and is dried to become fine powder, which is not preferable.

When changing the moisture content of the reduced water sludge, the situation when the fibrous organic matter is dispersed in free water changes. For example, when the water content of the reduced water sludge is small, the distance between the fibrous organic substances dispersed in free water becomes small. For this reason, when the dispersed fibrous organic matter is shrunk and rounded, the adjacent fibrous organic matter is easily entangled, and when the entangled organic matter is shrunk and rounded, the size of the rounded product formed is large. Become. And since the surface of the round object which became large size coats slaked lime and a granular material is formed, the size of a granular material also becomes large. For example, when the water content of the reduced water sludge is adjusted to 40 to 50% by mass, a granular material having an outer diameter of 2 to 20 mm in terms of a sphere can be obtained.

In addition, when the water content of the reduced water sludge is high, the distance between the fibrous organic substances dispersed in the free water increases. For this reason, when the dispersed fibrous organic matter is shrunk and rounded, the adjacent fibrous organic matter is not entangled and the dispersed fibrous organic matter is shrunk and rounded. The size of depends on the length of the fibrous organic material, and the size of the round material is smaller than when the adjacent fibrous organic materials are intertwined with each other. And since the surface of the round thing which became small size coats slaked lime and a granular material is formed, the size of a granular material also becomes small. For example, when the water content of the reduced water sludge is adjusted to more than 50% by mass and 75% by mass or less, a granular material having an outer diameter of 1 to 6 mm in terms of a sphere can be obtained.

Here, since the reaction in which slaked lime is generated from the moisture and quicklime in the reduced water sludge is an exothermic reaction, the temperature of the reduced water sludge rises to, for example, about 100 ° C., and pathogens in the reduced water sludge can be sterilized. it can. In addition, parasites and seeds contained in the reduced water sludge can be killed. As a result, the safety of the reduced water sludge can be ensured, and the influence on the ecosystem around the treatment plant 11 can be eliminated, and the reduced water sludge can be easily handled.

Further, since the surface of the round product formed by rounding the fibrous organic matter is covered with slaked lime, it is possible to prevent the emission of hydrogen sulfide (a main cause of bad odor) generated during the decomposition of the organic matter, and the treatment plant 11 Therefore, it is possible to prevent the generation of bad odor during sludge treatment. In addition, since the sludge is granular after the treatment, the sludge can be easily handled and the efficiency of the treatment work can be improved. Furthermore, since hydrogen sulfide can be prevented from being diffused, sulfurous acid gas is not generated at the treatment site 11, and sulfuric acid can be prevented from being generated. For this reason, environmental and hygienic and facility maintenance problems during the sludge treatment work can be solved and the treatment work becomes easy.

And the hydrogen sulfide generated in the decomposition process of the organic matter in the particulate matter is between the slaked lime covering the organic matter,
H ₂ S + Ca (OH) ₂ → CaS + 2H ₂ O
It is consumed to produce calcium sulfide (CaS). For this reason, generation | occurrence | production of a malodor can be prevented reliably until the period until decomposition | disassembly of organic substance is complete | finished.
In addition, since the produced | generated calcium sulfide will hydrolyze slowly and will change to calcium hydrogen sulfide and calcium hydroxide if there exists a water | moisture content, even if calcium sulfide decomposes | disassembles, generation | occurrence | production of a malodor can be prevented. The generated calcium sulfide absorbs moisture and carbon dioxide in moist air and generates hydrogen sulfide. However, the reaction rate when calcium sulfide generates moisture and water sulfide is high. Because it is slow, it does not substantially react in air at room temperature. Therefore, the granular material whose surface is coated with calcium sulfide exists stably in the atmosphere.

(Drying process)
The granular material produced by the first stirring and mixing device 14 is taken out via the belt conveyor 20, filled into a container (not shown), and the container filled with the granular material is charged into the dryer 24, and 100 Heating is performed at a temperature not lower than 150 ° C. and not higher than 150 ° C., and water reduction treatment is performed so that the moisture content of the granular material becomes 5 to 10% by mass. Thereby, the particulate matter can be sterilized to increase the safety of the particulate matter, and the water content can be adjusted, so that the particulate matter can be provided as an organic fertilizer having high safety and excellent convenience. When using the granular material as an organic fertilizer, the water content of the reduced water sludge is adjusted so that the size of the granular material is, for example, 1 to 6 mm in terms of a sphere.

Next, the sludge treatment method according to the second embodiment of the present invention will be described.
As shown in FIG. 3, the method for treating sludge according to the second embodiment is a method for producing roadbed material from sludge generated at a sewage or livestock manure treatment plant 11 and containing fibrous organic matter derived from food. A dehydration step of dehydrating part of the water from the sludge to produce a reduced sludge having a moisture content of 40% by mass to 75% by mass by agglomeration of fibrous organic matter, and a first agitation of the reduced sludge The mixture is received in the mixing device 14 and further mixed with the quicklime supplied from the quicklime storage means 13 to generate slaked lime by the reaction between the moisture in the water-reduced sludge and the quicklime, and the water-reduced sludge by the heat generated by the slaked lime generation reaction While heating the water, release the surface tension of the water in the reduced sludge to disperse the fibrous organic matter, adhere a part of the slaked lime to the surface where the dispersed organic matter has shrunk, and the surface is made of slaked lime. Manufacture coated granules And a granulating step that.

Furthermore, the sludge treatment method according to the second example was obtained by a firing step of firing the granular material produced in the granulation step at a temperature of 800 ° C. or more and 1200 ° C. or less in the firing furnace 25, and the firing step. It was obtained by adding water and quicklime to incinerated ash and mixing them, and manufacturing a first mixture in which the incinerated ash was dispersed in slaked lime generated by the reaction between quicklime and water, and the first mixture manufacturing process. Lightly-burned magnesia is further added to and mixed with the first mixture, and magnesium hydroxide produced by the reaction of light-burned magnesia and moisture in the first mixture is dispersed in the first mixture, and the first mixture is dispersed. A step of producing a second mixture that gradually solidifies while producing a hydrate by reaction of slaked lime and magnesium hydroxide therein, and before the second mixture solidifies, the second mixture is A molding process to form and solidify It has.

Here, since the dehydration step and the granulation step can be performed by the same method as the sludge treatment method according to the first embodiment, the description is omitted, and the firing step, the step of producing the first mixture, The process for producing the second mixture and the molding process will be described.
(Baking process)
When the particulate matter is fired in the firing furnace 25, the organic matter disappears by combustion, and incinerated ash derived from the inorganic matter attached to the fibrous organic matter is obtained. The incinerated ash contains quick lime in which the slaked lime that has been coated with the organic matter is changed.

(Process for producing the first mixture)
When the incinerated ash supplied from the firing furnace 25, moisture, and quicklime from the quicklime storage means 13 are mixed by the first stirring and mixing device 14, the quicklime contained in the incinerated ash and the added quicklime react with moisture, respectively. The slaked lime is produced | generated and the 1st mixture disperse | distributed in the slaked lime which the incineration ash produced | generated is produced | generated. Here, the weight of the quicklime mixed with the incinerated ash is, for example, 0.1 to 0.3 when expressed by the weight ratio of the weight of the quicklime to the weight of the incinerated ash. In addition, in order to disperse incineration ash uniformly in slaked lime, the amount of quick lime added to the incineration ash needs to be at least 0.1 by weight. Moreover, when the amount of quick lime added to the incinerated ash exceeds 0.3 by weight, the incinerated ash is uniformly dispersed in the slaked lime simply by increasing the distance of the incinerated ash dispersed in the slaked lime. The effect is not changed, and the use cost of quick lime increases, which is not preferable.

(Step of producing the second mixture)
In the first stirring and mixing device 14, when the light-burned magnesia from the light-burning magnesia storage means 26 is mixed with the generated first mixture, the water in the first mixture and the light-burning magnesia are mixed in the first mixture. Between,
MgO + H ₂ O → Mg (OH) ₂
To produce magnesium hydroxide (Mg (OH) ₂ ). The produced magnesium hydroxide is uniformly dispersed in the first mixture. The magnesium hydroxide dispersed in the first mixture is between slaked lime in the first mixture,
Ca (OH) ₂ + Mg (OH) ₂ → CaMg (OH) ₄
Thus, a second mixture is produced which gradually solidifies while producing a calcium hydrate magnesium hydroxide hydrate. Note that the weight of the light-burned magnesia added to the first mixture is, for example, 1 to 3 when expressed by the weight ratio of the light-burned magnesia to the weight of quicklime. Here, in order to solidify the 2nd mixture, the usage-amount of the light-burning magnesia with respect to quick lime needs to be set to at least 1 by weight ratio. Moreover, even if light-burning magnesia is added in a weight ratio exceeding 3, there is no significant increase in the effect of solidifying the second mixture, and this is not preferable because the production cost increases as the use of light-burning magnesia increases.

(Molding process)
Since the reaction of forming calcium hydrate tetrahydrate between slaked lime and magnesium hydroxide proceeds slowly, before the second mixture produced by the first stirring and mixing device 14 solidifies, The second mixture is formed into a roadbed material having a certain size (for example, a size of 10 to 30 mm) using the press molding machine 30. And the obtained roadbed material is left still, the production | generation of the hydrate of calcium tetrahydroxide magnesium is advanced in the 2nd mixture which forms the roadbed material, and a roadbed material is solidified.

The present invention has been described above with reference to the embodiments. However, the present invention is not limited to the configurations described in the above-described embodiments, and is within the scope of the matters described in the claims. Other possible embodiments and modifications are also included.
For example, the sludge treatment equipment is composed of a reduced water sludge production device, quick lime storage means, a first stirring and mixing device, and a dryer, and can also be used as an organic fertilizer production device. It can also be used as a roadbed material manufacturing apparatus comprising the means, the first stirring and mixing apparatus, the baking furnace, the light-burning magnesia storage means, and the press molding machine. Moreover, you may provide the 1st, 2nd stirring and mixing apparatus separately.

Since the essential treatment of sludge (fibrous organic matter treatment), the diffusion of hydrogen sulfide generated during sludge treatment can be prevented, the generation of sulfurous acid gas and sulfuric acid at the treatment plant can be prevented, and sludge treatment work Can solve environmental, hygiene and facility maintenance problems. And since the size of the granular material obtained by treating the sludge can be easily adjusted, it is not necessary to crush the granular material during the transportation of the granular material, and generation of dust can be prevented, and the sludge (granular material) Efficiency of final disposal (landfill disposal) can be achieved.
In addition, during the treatment of sludge, the granular material is heated at a temperature of 100 ° C. or higher and 150 ° C. or lower, so that the granular material is sterilized and moisture is adjusted. Therefore, the granular material is used as an organic fertilizer with high safety, quality and convenience. Available. Furthermore, what is manufactured by adding water, quicklime, and light-burned magnesia to incinerated ash obtained by firing the granular material has self-curing properties, so it must be solidified after being molded into a specific shape. Thus, for example, construction materials such as roadbed materials can be manufactured. Thereby, effective utilization of sludge can be aimed at.

10: Sludge treatment equipment, 11: Treatment plant, 12: Reduced water sludge production device, 13: Quicklime storage means, 14: First stirring and mixing device, 15: Pump, 16: Transport pipe, 17: Filter press, 18: Belt conveyor, 20: belt conveyor, 21: quick lime storage hopper, 22: quick lime cutting machine, 23: quick lime transport pipe, 24: dryer, 25: firing furnace, 26: light-burning magnesia storage means, 27: light-burning magnesia storage Hopper, 28: Light-burning magnesia cutting machine, 29: Light-burning magnesia transport pipe, 30: Press molding machine

Claims

It is generated at a sewage or livestock manure treatment plant, and a part of water is dehydrated from sludge containing fibrous organic matter derived from food, the fibrous organic matter is aggregated, and the moisture content is 40 mass% to 75 mass%. A dehydration process for producing the following reduced water sludge;
Quick lime is added to and mixed with the reduced water sludge, slaked lime is generated by the reaction of the moisture in the reduced water sludge and the quick lime, and the reduced water sludge is heated while heating the reduced sludge with heat generated by the reaction of generating the slaked lime. The surface tension of the moisture in the inside is released to disperse the fibrous organic matter, and a part of the slaked lime is attached to the surface where the dispersed organic matter is shrunk and rounded, and the surface is coated with the slaked lime. A granulating step for producing a product,
The hydrogen sulfide generated in the process of decomposing the organic matter in the granule produced in the granulation step is reacted with the slaked lime covering the organic matter to change to calcium sulfide. Sludge treatment method.
The sludge treatment method according to claim 1, wherein the water content of the reduced water sludge is changed to adjust the size of the granular material.
The sludge treatment method according to claim 1 or 2, wherein the granular material produced in the granulating step is further heated at a temperature of 100 ° C or higher and 150 ° C or lower to adjust the water content in the granular material. A method for treating sludge, comprising a step.
The method for treating sludge according to claim 1 or 2, wherein the granule produced in the granulation step is calcined and the organic matter in the granule is burned to disappear.
Adding and mixing moisture and quicklime to the incinerated ash obtained in the firing step, producing a first mixture in which the incinerated ash is dispersed in slaked lime generated by the reaction between the quicklime and the moisture;
Magnesium hydroxide produced by further adding light-burned magnesia to the first mixture obtained in the manufacturing process of the first mixture and mixing, and reacting the light-burned magnesia with moisture in the first mixture. In the first mixture to produce a second mixture that gradually solidifies while producing a hydrate by reaction of the slaked lime in the first mixture with the magnesium hydroxide. Have
A method for treating sludge, comprising forming the second mixture and solidifying the second mixture into a specific shape before the second mixture is solidified.
Occurring in a sewage or livestock manure treatment plant, a part of the water is dehydrated from sludge containing fibrous organic matter derived from food, and the fibrous organic matter aggregates so that the moisture content is 40% by mass or more and 75% by mass or less. Reduced water sludge production equipment for producing reduced water sludge in the range of
Quick lime storage means for storing quick lime used for the treatment of the sludge;
A first stirring and mixing device,
In the first stirring and mixing device, the reduced water sludge from the reduced water sludge production device and quick lime supplied from the quick lime storage means are received and mixed, and slaked lime is formed by a reaction between the moisture in the reduced water sludge and the quick lime. While heating the water-reduced sludge with the heat generated by the reaction of forming the slaked lime, the surface tension of water in the water-reduced sludge is released to disperse the fibrous organic matter, and the dispersed organic matter is shrunk. A sludge treatment facility characterized in that a part of the slaked lime is adhered to a rounded surface to produce a granular material whose surface is coated with the slaked lime.
6. The sludge treatment facility according to claim 5, further comprising drying means for reducing water by heating the granular material produced by the first stirring and mixing device at a temperature of 100 ° C. or higher and 150 ° C. or lower. Sludge treatment equipment characterized by
The sludge treatment facility according to claim 5, further comprising a firing furnace for producing incinerated ash by firing the granular material produced by the first stirring and mixing device at a temperature of 800 ° C or higher and 1200 ° C or lower,
Light-burning magnesia storage means for storing light-burning magnesia used for the treatment of the incineration ash,
The incinerated ash from the calcining furnace, the quick lime from the quick lime storage means, and water are mixed to produce a first mixture, and the light burned magnesia received from the light burned magnesia storage means is added to the first mixture. A second stirring and mixing device for mixing to produce a second mixture;
Molding means for shaping the second mixture and solidifying the second mixture into a specific shape before the second mixture produced by the second stirring and mixing device solidifies;
The first mixture is produced by dispersing the incinerated ash in slaked lime generated by the reaction of the mixed quicklime and moisture, and the second mixture is the light burned magnesia and the first mixture. Magnesium hydroxide produced by reaction with moisture in the first mixture is produced by being dispersed in the first mixture, and the second mixture is a mixture of the slaked lime and the magnesium hydroxide in the first mixture. A sludge treatment facility that gradually solidifies while producing hydrates by reaction.
The sludge treatment facility according to claim 7, wherein the second stirring and mixing device is also used as the first stirring and mixing device.