Sludge treatment device, sludge treatment system, and sludge treatment method

Abstract

To provide a sludge treatment apparatus, a sludge treatment system and a sludge treatment method capable of stably reducing the water content of dehydrated sludge and saving energy in sludge treatment.SOLUTION: A sludge treatment apparatus comprising a mixing unit for producing a mixture of sludge and wood chips, and a crushing unit for crushing the mixture produced in the mixing unit. And, a sludge treatment system comprising the apparatus, and a sludge treatment method using the apparatus. According to the invention, sludge and wood chips can be mixed first and then crushed in a wet state, thereby suppressing the generation of dust, and depressing decrease in the mixing efficiency of sludge and wood chips. Energy consumption of the apparatus can be reduced when fine wood chips are dispersed in sludge. In addition, wood chips can effectively function as a dehydrating agent or a dehydration aid to stably reduce the content of water in dehydrated sludge.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sludge treatment apparatus, a sludge treatment system, and a sludge treatment method. [Background technology]

[0002] It is generally known that sludge generated in wastewater treatment or the like is dehydrated using a dehydrator and then either treated as industrial waste or compost material, or incinerated as biomass fuel in an incineration facility. In either case, it is required to reduce the moisture content of the dehydrated sludge as much as possible, taking into account the treatment efficiency and utility value of the dehydrated sludge.

[0003] For example, Patent Document 1 describes a method for drying sludge in which solid fine particles made of wood biomass including wood chips and coal are dispersed in sludge using a premixer, and then the sludge is dried by feeding the dispersed solid fine particles into a dryer. Patent Document 1 also describes a method for pulverizing solid materials using a pulverizer to produce fine particles, which are then mixed with sludge. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-254921 A Summary of the Invention [Problem to be solved by the invention]

[0005] As described in Patent Document 1, when solids (fine solid granules) such as woody biomass that have been finely granulated in advance are mixed with sludge and the fine solid granules are used as a dewatering aid, there is a problem that the working environment is significantly deteriorated due to the generation of dust when the solids are crushed. In addition, since the finely granulated solids tend to float relative to the sludge, there is a problem that extra mixing time and power required for mixing in a premixer are required to uniformly mix (disperse) the fine solid granules and sludge. On the other hand, if solid wood biomass is simply mixed with sludge without being crushed, the water absorption rate of the solid is low and the absorbed water is difficult to remove during dehydration, resulting in the problem that the moisture content of the dehydrated sludge does not decrease.

[0006] An object of the present invention is to provide a sludge treatment apparatus, a sludge treatment system, and a sludge treatment method that can stably reduce the moisture content of dewatered sludge and achieve energy savings in sludge treatment. [Means for solving the problem]

[0007] As a result of intensive research into the above-mentioned problems, the inventors discovered that in sludge treatment, by mixing wood chips with sludge and then performing a crushing process, it is possible to reduce the moisture content of the dewatered sludge and also to save energy, and thus completed the present invention. That is, the present invention relates to the following sludge treatment device, sludge treatment system, and sludge treatment method.

[0008] The sludge treatment device of the present invention, which is intended to solve the above problems, is characterized by having a mixing section that produces a mixture of sludge and wood chips, and a crushing section that crushes the mixture produced in the mixing section. The sludge treatment device of the present invention first mixes the sludge with wood chips and then crushes them in a wet state, which makes it possible to suppress the generation of dust and to suppress a decrease in the mixing efficiency of the sludge and wood chips. This makes it possible to reduce the energy consumed by the device when dispersing the finely ground wood chips into the sludge, and also makes it possible for the wood chips to function effectively as a dehydrating agent or dehydration aid.

[0009] In one embodiment of the sludge treatment device of the present invention, the crushing blades of the crushing section have a mesh width of less than 10 mm. According to this feature, the wood chips dispersed in the sludge can be sufficiently crushed to a size that effectively functions as a dehydrating agent or dehydration aid, and as a result, the dehydration rate of the dehydrated sludge can be effectively reduced.

[0010] In addition, one embodiment of the sludge treatment device of the present invention is characterized in that a return line is provided for returning the mixture crushed in the crushing section to the mixing section. According to this feature, the mixture can be repeatedly crushed and mixed, making it possible to sufficiently crush the wood chips in the mixture.

[0011] A sludge treatment system according to the present invention for solving the above problems is characterized by comprising any one of the sludge treatment devices described above, a coagulation tank, and a dewatering machine. In the sludge treatment system of the present invention, the wood chips in the mixture discharged from the sludge treatment device are broken down into fine particles and dispersed evenly throughout the sludge, so that the wood chips function effectively as a dehydrating agent or dehydration aid during flocculation and dehydration, making it possible to stably and effectively reduce the moisture content of the dehydrated sludge.

[0012] In addition, the sludge treatment method of the present invention for solving the above problems is characterized by including a mixing step for producing a mixture of sludge and wood chips, and a crushing step for crushing the mixture produced in the mixing step. In the sludge treatment method of the present invention, the sludge and wood chips are mixed first and then crushed in a wet state, which makes it possible to suppress the generation of dust and to suppress a decrease in the mixing efficiency of the sludge and wood chips. This makes it easier to disperse the finely ground wood chips in the sludge, saves energy during mixing, and allows the wood chips to effectively function as a dehydrating agent or dehydration aid. Effect of the Invention

[0013] According to the present invention, it is possible to provide a sludge treatment apparatus, a sludge treatment system, and a sludge treatment method that can stably reduce the moisture content of dewatered sludge and achieve energy savings in sludge treatment. [Brief description of the drawings]

[0014] [Figure 1]FIG. 1 is a schematic explanatory diagram of a sludge treatment device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic explanatory diagram showing another aspect of the sludge treatment device in the first embodiment of the present invention. [Diagram 3] FIG. 1 is a schematic explanatory diagram of a sludge treatment system according to a first embodiment of the present invention. [Figure 4] 4 is a graph showing the relationship between the moisture content of dewatered sludge obtained by sludge treatment using a sludge treatment system equipped with sludge treatment apparatuses of Examples and Comparative Examples according to the first embodiment of the present invention and the mesh width of the crushing blades. [Diagram 5] FIG. 4 is a schematic explanatory diagram of a sludge treatment device according to a second embodiment of the present invention. [Figure 6] FIG. 4 is a schematic explanatory diagram showing another aspect of a sludge treatment device in the second embodiment of the present invention. [Figure 7] FIG. 4 is a schematic explanatory diagram showing another aspect of a sludge treatment device in the second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The sludge treatment apparatus, sludge treatment system and sludge treatment method of the present invention are used in sludge treatment.

[0016] The sludge to be treated in the present invention may be any kind of dispersion liquid in which particulate solids are dispersed in a liquid or any kind of muddy material, including, for example, various kinds of sludge such as primary settling sludge, excess sludge, and flocculated sludge generated in sewage treatment plants and wastewater treatment plants, paper sludge from paper factories, industrial wastewater from food factories and plating factories, and pigment wastewater.

[0017] Hereinafter, embodiments of the sludge treatment device, sludge treatment system, and sludge treatment method according to the present invention will be described in detail with reference to the drawings. The sludge treatment method according to the present invention is replaced with the description of the configuration and operation of the sludge treatment device and sludge treatment system according to the present invention. It should be noted that the sludge treatment device, sludge treatment system, and sludge treatment method described in the embodiments are merely examples provided to explain the sludge treatment device, sludge treatment system, and sludge treatment method of the present invention, and are not limited thereto.

[0018] [First embodiment] (Sludge treatment equipment) The sludge treatment apparatus of the present invention is an apparatus for performing pretreatment to enhance the dewatering efficiency of the sludge to be treated.

[0019] FIG. 1 is a schematic explanatory view showing a sludge treatment apparatus according to a first embodiment of the present invention. 1, the sludge treatment device 1a according to this embodiment includes a mixing section 2 that mixes sludge S and wood chips C to produce a mixture M, and a crushing section 3 that crushes the mixture M. The sludge treatment device 1a also includes a line L1 that supplies the sludge S to the mixing section 2, a line L2 that supplies the wood chips C to the mixing section 2, a line L3 that supplies the mixture M produced in the mixing section 2 to the crushing section 3, and a line L4 that discharges the mixture M1 crushed in the crushing section 3.

[0020] The mixing section 2 is for carrying out a mixing step in which the sludge S and the wood chips C are mixed to generate a mixture M.

[0021] The wood chips C to be mixed with the sludge S are not particularly limited as long as they are wood chips that have been cut or crushed into small pieces. Examples include waste materials such as thinned wood, construction waste, and lumber scraps, as well as small pieces of wood that are used as raw materials for pulp products or are generated during the manufacturing process of pulp products.

[0022] The raw material and size of the wood chips C may be of the standard that is generally used for wood chips. It is preferable to use wood chips having a size of, for example, 10 mm or more as the wood chips C. This makes it possible to suppress the generation of dust and to suppress the deterioration of the working environment during the transport and mixing process of the wood chips C. In addition, when the wood chips C are mixed with the sludge S, it is possible to obtain a mixture M in which the wood chips C are dispersed approximately uniformly without floating up. The wood chips C may be, for example, those that meet the quality standards for fuel wood chips (established on November 13, 2014) set by the Council for the Promotion of Wood Biomass Energy Utilization. In this case, examples of the size of the wood chips C include those in which 80% or more of the chip weight is 4 to 26 mm (size category P26) and those in which 80% or more of the chip weight is 8 to 32 mm (size category P32).

[0023] The mixing section 2 is not particularly limited as long as it can mix the sludge S and wood chips C to produce the mixture M without crushing the wood chips C in advance. For example, the sludge S and wood chips C introduced into the mixing tank are stirred by a stirring mechanism in the mixing tank, or the mixing tank itself is rotated to mix. Examples of the stirring mechanism include a stirring blade having a rotating shaft or a mechanism that rotates a screw, and a mechanism that provides two sets of screws and kneads the materials by rotating the screws in opposite directions. In the process of mixing the sludge S and the wood chips C in the mixing section 2, some of the wood chips C may be crushed. However, since the wood chips C are likely to become unevenly crushed in the mixing section 2, it is not necessary to actively crush the wood chips C in the mixing section 2.

[0024] The crushing section 3 is for carrying out a crushing step of crushing the mixture M produced in the mixing section 2.

[0025] The crushing unit 3 is not particularly limited as long as it can crush the mixture M. In particular, it is sufficient that it can crush the wood chips C in the mixture M. The mixture M1 crushed by the crushing unit 3 contains finely granulated wood chips C in a state of being sufficiently dispersed in the sludge S. This increases the water absorption efficiency of the wood chips C in absorbing the moisture in the sludge S, and also makes it easier to remove the absorbed moisture.

[0026] The crushing section 3 may be, for example, a crushing pump 31 provided in the subsequent stage of the mixing section 2 as shown in FIG.

[0027] The crushing pump 31 includes crushing means for crushing the object to be crushed, and transporting means for transporting the object to be crushed. The crushing pump 31 in this embodiment is not particularly limited as long as it is capable of crushing the material to be crushed (mixture M in this embodiment) in a wet manner and pumping the material to be crushed to a downstream stage of the crushing section 3 (e.g., coagulation tank 4 or dehydrator 5, etc.), and there are no particular limitations on the detailed structure.

[0028] The crushing means in the crushing pump 31 may be, for example, a rotating crushing blade, a fixed crushing blade, or both. The transport means in the crushing pump 31 may be, for example, a centrifugal pump, a positive displacement pump, or the like. In addition, the positional relationship between the crushing means and the transfer means in the crushing pump 31 is not particularly limited. For example, when the crushing means is provided downstream of the transfer means, the material to be crushed can be forcibly supplied to the crushing means side by the transfer means. This allows the material to be stably transferred, such as the mixture M in this embodiment, which is a mixture of solids and liquids, and allows the solids to be efficiently crushed. On the other hand, when the crushing means is provided upstream of the transfer means, the crushed material to be crushed (mixture M1 in this embodiment) can be efficiently pumped with a larger pressure to the subsequent stage of the crushing section 3 (for example, the coagulation tank 4 or the dehydrator 5, etc.).

[0029] By using the crushing pump 31 as the crushing section 3, crushing of the mixture M and pumping of the crushed mixture M1 can be performed by a single device. This makes it possible to reduce the space and energy required for the sludge treatment device 1a.

[0030] The crushing unit 3 is not limited to being composed of a single device such as the crushing pump 31. FIG. 2 shows another aspect of the crushing section of this embodiment. Another embodiment of the crushing section 3 includes a crusher 32 and a wet-type transfer pump 33, as shown in Fig. 2. The structures of the crusher 32 and the transfer pump 33 are not particularly limited, and they may each be of a known structure. As shown in Fig. 2, by providing separate structures for crushing and transferring the mixture M in the crushing section 3, the crushing efficiency of the mixture M can be increased, and it becomes easier to identify the cause of an abnormality and take action.

[0031] There is no particular limitation on the crushing means in the crushing unit 3. For example, shearing by a crushing blade or the like, impact by a hammer or the like, or both shearing and impacting may be used. In addition, since the mixture M to be crushed in this embodiment contains wood chips C that have already been broken into small pieces, it is preferable to crush the mixture M by passing it through slits having crushing blades in the crushing section 3. This makes it possible to maintain high crushing efficiency of the mixture M. In addition, the length (mesh width) of the slit having the crushing blade is not particularly limited, but it is preferable to set it to less than 10 mm based on the results of the examples described later. This makes it possible to effectively reduce the moisture content of the dewatered sludge S1 obtained by flocculating and dewatering the crushed mixture M1.

[0032] In the sludge treatment device 1a of this embodiment, the wood chips C are first mixed with the sludge S, and then crushed in a wet state. This prevents dust from being generated and makes it possible to suppress a decrease in the mixing efficiency of the sludge S and the wood chips C. Furthermore, the sludge treatment device 1a of this embodiment makes it possible to easily and evenly disperse the finely granulated wood chips C in the sludge S, thereby enabling the sludge treatment device 1a to reduce energy consumption and to allow the wood chips C to effectively function as a dehydrating agent or dehydration aid.

[0033] (Sludge treatment system) The sludge treatment system of the present invention is a treatment system for obtaining dewatered sludge with a low water content by using the above-mentioned sludge treatment apparatus.

[0034] FIG. 3 is a schematic explanatory diagram of the sludge treatment system of this embodiment. 3, the sludge treatment system 10 of this embodiment includes the above-mentioned sludge treatment device 1a, a coagulation tank 4, and a dehydrator 5. The sludge treatment system 10 also includes a line L4 for supplying the crushed mixture M1 discharged from the sludge treatment device 1a to the coagulation tank 4, a line L5 for supplying the coagulated mixture M2 discharged from the coagulation tank 4 to the dehydrator 5, a line L6 for discharging the dehydrated sludge S1 dehydrated by the dehydrator 5 to the outside of the system, and a line L7 for discharging the dehydrated separated liquid.

[0035] The coagulation tank 4 is for coagulating the crushed mixture M1 supplied from the crushing section 3 of the sludge treatment device 1a. As shown in Fig. 3, the coagulation tank 4 is provided with a coagulant adding section 41 for adding a coagulant.

[0036] The flocculation tank 4 is not particularly limited in its detailed structure as long as it can mix the crushed mixture M1 with a flocculant and send it to the dehydrator 5. For example, as shown in FIG. 3, it may be equipped with a cylindrical tank body 42 and a bottom 43 made of a circular flat plate, and also equipped with an outlet 44 for discharging the flocculated mixture M1 as a flocculated mixture M2. At this time, the flocculated mixture M2 discharged from the outlet 44 is supplied to the dehydrator 5 via a line L5. The shapes of the tank body 42 and the bottom 43 are not limited thereto, and examples thereof include a tank body 42 having a rectangular parallelepiped shape and a bottom 43 having a cone shape.

[0037] The flocculant added from the flocculant adding section 41 is not particularly limited and may be either an inorganic flocculant or a polymer flocculant, so long as it is capable of flocculating particles in the sludge S. Examples of inorganic flocculants include polyferric sulfate, ferric chloride, polysilica iron, aluminum sulfate, and polyaluminum chloride. Examples of polymer flocculants include cationic polymer flocculants such as polyaminoalkyl methacrylate, polyethyleneimine, halogenated polydiallylammonium, chitosan, and urea-formaldehyde resin; anionic polymer flocculants such as sodium polyacrylate, partial hydrolysates of polyacrylamide, partially sulfomethylated polyacrylamide, and poly(2-acrylamide)-2-methylpropane sulfate; nonionic polymer flocculants such as polyacrylamide and polyethylene oxide; and amphoteric polymer flocculants such as copolymers of acrylamide, aminoalkyl methacrylate, and sodium acrylate. In addition, the flocculant in this embodiment may be used alone or in combination of multiple types. In addition, an inorganic flocculant and a polymer flocculant may be used in combination. When multiple types of flocculants are used in combination, the flocculants may be mixed and used, or each may be added separately.

[0038] The dehydrator 5 is for dehydrating the flocculated mixture M2 supplied from the flocculation tank 4. The dehydrator 5 is not particularly limited as long as it can dehydrate the flocculated mixture M2 to produce dehydrated sludge S1. Examples of the dehydrator include a screw press type dehydrator, a centrifugal dehydrator, a filter press, a belt press, and a multiple disk type dehydrator. The dehydrated sludge S1 dewatered by the dehydrator 5 is discharged outside the system via a line L6. The dehydrated sludge S1 discharged outside the system may be incinerated, buried, or otherwise disposed of, or may be reused as compost or fuel.

[0039] The sludge treatment system 10 of this embodiment performs flocculation and dehydration treatment on the mixture M1 discharged from the sludge treatment device 1a to obtain dehydrated sludge S1. In the mixture M1 discharged from the sludge treatment device 1a, the wood chips C are finely divided and evenly dispersed in the sludge S, so that the wood chips C effectively function as a dehydrating agent or dehydration aid during flocculation and dehydration. This makes it possible to stably and effectively reduce the moisture content of the dehydrated sludge S1. EXAMPLES

[0040] The sludge treatment device and the sludge treatment system of the present invention will be described below based on examples and comparative examples. Note that the present invention is not limited to these examples.

[0041] Sludge S was treated using the sludge treatment device and sludge treatment system of the Example and Comparative Example. The sludge treatment device and sludge treatment system of the Example are based on the above-mentioned sludge treatment device 1a and sludge treatment system 10. The sludge treatment device and sludge treatment system of the Comparative Example are the sludge treatment device and sludge treatment system of the Example from which the crushing unit 3 has been removed.

[0042] In the sludge treatment devices and sludge treatment systems of the examples and comparative examples, the mixer 2, flocculation section 4, and dehydrator 5 were all of the same structure. The wood chips C mixed in the mixer 2 were 20 mm pieces. The flocculants added in the flocculation section 4 were an amphoteric polymer flocculant and a cationic polymer flocculant. The dehydrator 5 was a screw press type dehydrator.

[0043] A crushing pump 31 was used as the crushing section 3 in the embodiment. At this time, the mesh width of the crushing blade, which is the crushing means of the crushing pump 31, was changed between 0.5 mm and 10 mm, and the sludge S was treated for each.

[0044] The moisture content was measured for the dewatered sludge S1 discharged from the sludge treatment system of the embodiment and the dewatered sludge SC discharged from the sludge treatment system of the comparative example. The moisture content was measured according to the following method. First, the weight of solid matter in the sample (dewatered sludge S1 or dewatered sludge SC) (= mass of the evaporating dish containing the residue-mass of the evaporating dish) was calculated based on JIS K0102. Next, the solid matter ratio of the sample was calculated by dividing the weight of the solid matter by the weight of the sample. Then, the moisture content was calculated by subtracting the calculated solid matter ratio from 1 (= 1-solid matter ratio) and multiplying this value by 100. The results are shown in the graph of Figure 4. In the graph of Figure 4, the horizontal axis represents the mesh width of the crushing blade, and the vertical axis represents the moisture content of the dewatered sludge S1 and the dewatered sludge SC.

[0045] 4, it can be seen that when the mesh width of the crushing blade is smaller than 10 mm, the moisture content of the dewatered sludge S1 is lower than the moisture content of the dewatered sludge SC (48%). In particular, when the mesh width of the crushing blade is 1 mm or less, it is possible to reduce the moisture content of the dewatered sludge S1 to 45%.

[0046] The moisture content of the dewatered sludge S1 is closely related to the amount of heat generated by the dewatered sludge S1 when the dewatered sludge S1 is incinerated or reused as fuel. Therefore, by decreasing the moisture content of the dewatered sludge S1, the amount of heat generated by the dewatered sludge S1 can be increased, making it possible to stabilize the spontaneous combustion operation and save energy in the incineration of the dewatered sludge S1, and to increase the efficiency of the fuel reused from the dewatered sludge S1.

[0047] As described above, the sludge treatment device and sludge treatment system of this embodiment make it possible to stably reduce the moisture content of dewatered sludge in sludge treatment and to reduce the energy required for the sludge treatment itself. It also makes it possible to reduce energy required for the incineration of the dewatered sludge and to increase the efficiency of the reuse of the dewatered sludge.

[0048] [Second embodiment] Fig. 5 is a schematic explanatory diagram showing a sludge treatment apparatus 1b in a second embodiment of the present invention, and Fig. 6 is a schematic explanatory diagram showing another aspect of the sludge treatment apparatus 1b in the second embodiment of the present invention. As shown in Figures 5 and 6, the sludge treatment device 1b of the second embodiment is provided with a return line 6 for returning the mixture M1 crushed in the crushing section 3 of the sludge treatment device 1a of the first embodiment to the mixing section 2. Note that a description of the configurations that are the same as those in the first embodiment will be omitted.

[0049] The return line 6 returns the mixture M1 crushed in the crushing section 3 to the mixing section 2. This allows the mixture M to be repeatedly crushed and mixed, making it possible to increase the crushing efficiency of the wood chips C in the mixture M. In addition, the increased crushing efficiency of the wood chips C makes it possible to reduce the moisture content of the dewatered sludge S1.

[0050] The return line 6 may be any line that returns the mixture M1 crushed in the crushing section 3 to the mixing section 2, and there are no particular limitations on the detailed structure. For example, as shown in FIG. 5, in the case where the crushing section 3 is composed of a crushing pump 31, the return line 6 may be a branch line provided on the line L4 that supplies the crushed mixture M1 discharged from the crushing pump 31 to the coagulation tank 4. The amount of mixture M1 returned by the branch line may be constant regardless of the treatment conditions, etc., or may be controlled based on the treatment conditions and the properties of the mixture M1. For example, a measuring section that measures the water content and fluidity (viscosity) of the mixture M1 may be provided upstream of the return line 6, and the amount of mixture M1 returned by the return line 6 may be controlled based on the measurement results of the measuring section. This makes it possible to subject the wood chips C in the mixture M1 to sufficiently fine grained grains for coagulation and dehydration treatment.

[0051] . FIG. 6 shows another embodiment of the return line 6 in the case where the crushing section 3 comprises a crusher 32 and a transfer pump 33. As shown in Fig. 6, a crusher 32 and a transfer pump 33 are arranged in series from the upstream side, and a line for returning a part of the mixture M1 discharged from the transfer pump 33 side to the mixing section 2 is used as a return line 6. In this case, the amount of the mixture M1 to be returned may be controlled based on the measurement results of the measurement section described above. Another control means may be provided between the crusher 32 and the transfer pump 33 in a separation section that separates the mixture M1 based on the size of the solid content, such as a mesh (sieve) or a slit, and the solid that passes through the separation section is transferred to the subsequent stage by the transfer pump 33, and the rest is returned by the return line 6.

[0052] FIG. 7 shows another embodiment of the return line 6 in the case where the crushing section 3 is composed of a crushing pump 31 and a transfer pump 33. As shown in FIG. 7, the crushing pump 31 and the transfer pump 33 are arranged in parallel, a part of the mixture M discharged from the mixing section 2 is introduced into the crushing pump 31, and the return line 6 is used to return the entire amount of the mixture M1 discharged from the crushing pump 31 to the mixing section 2. In this case, the amount of the mixture M introduced into the crushing pump 31 may be a constant amount, or may be controlled based on the processing conditions and the properties of the mixture M. As a means for controlling the amount of the mixture M introduced into the crushing pump 31, for example, the above-mentioned separation section is provided in front of the transfer pump 33, and the mixture that does not pass through the separation section is introduced into the crushing pump 31.

[0053] The sludge treatment device 1b of this embodiment can be used as the sludge treatment device of the sludge treatment system 10 of the first embodiment. This allows the mixture M1 in which the wood chips C have been sufficiently pulverized to be supplied to the coagulation tank 4 and the dehydrator 5, making it possible to stably reduce the moisture content of the dewatered sludge S1.

[0054] According to this embodiment, the mixture of sludge and wood chips can be repeatedly crushed and mixed, and the crushing efficiency of the wood chips in the mixture can be increased. In addition, the increased crushing efficiency of the wood chips makes it possible to stably reduce the moisture content of the dewatered sludge.

[0055] The above-mentioned embodiments are examples of the sludge treatment device, sludge treatment system, and sludge treatment method according to the present invention. The sludge treatment device, sludge treatment system, and sludge treatment method according to the present invention are not limited to the above-mentioned embodiments, and the sludge treatment device, sludge treatment system, and sludge treatment method according to the above-mentioned embodiments may be modified within the scope of the gist of the claims.

[0056] For example, a dewatered sludge transport system may be provided to transport the dewatered sludge discharged from the sludge treatment system of this embodiment. For example, the dewatered sludge transport system may be one that applies stress to the dewatered sludge or one that transports dewatered sludge that has been crushed and kneaded. In particular, by crushing and kneading the dewatered sludge, the sol state of the dewatered sludge can be maintained during transportation. This makes it possible to transport dewatered sludge with reduced piping resistance, even when the water content of the dewatered sludge is low and the fluidity of the dewatered sludge is poor. [Industrial Applicability]

[0057] The sludge treatment apparatus, sludge treatment system and sludge treatment method of the present invention are suitably used for treating various types of sludge. [Explanation of symbols]

[0058] 1a, 1b sludge treatment apparatus, 10 sludge treatment system, 2 mixing section, 3 crushing section, 31 crushing pump, 32 crusher, 33 transfer pump, 4 coagulation tank, 41 coagulant addition section, 42 tank body, 43 bottom, 44 discharge port, 5 dehydrator, 6 return line, L1 to L7 lines, C wood chips, M mixture, M1 crushed mixture, M2 coagulated mixture, S sludge, S1 dewatered sludge, SC dewatered sludge in comparative example

Claims

1. A mixing section for generating a mixture of sludge and wood chips; A crushing section for crushing the mixture produced in the mixing section; An agglomeration unit that aggregates the mixture crushed in the crushing unit, The wood chips are crushed by the crushing unit, The crushing blade of the crushing unit has a mesh width of less than 10 mm, A sludge treatment device, wherein the mixture flocculated in the flocculation section is dewatered after flocculation; a dehydrator that dehydrates the mixture supplied from the flocculation section.

2. 2. The sludge treatment system according to claim 1, wherein the mesh width of the crushing blade of the crushing unit is 5 mm or less.

3. 3. The sludge treatment system according to claim 1, further comprising a return line for returning the mixture crushed in the crushing section to the mixing section.

4. A mixing step for generating a mixture of sludge and wood chips; A crushing step of crushing the mixture produced in the mixing step in a crushing section; an agglomeration step of agglomerating the mixture crushed in the crushing step; A dehydration step of dehydrating the mixture obtained in the agglomeration step, The wood chips are crushed by the crushing step, A sludge treatment method, characterized in that the mesh width of the crushing blade of the crushing unit is less than 10 mm.

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