JP2004073967A - Equipment and method for dehydrating and drying sludge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an equipment for dehydrating and drying sludge, which has press membranes having a thermal conductivity sufficient for heating of sludge, has a structure of uniformly distributing the flow rate of the hot water and vacuum degree, is short in the time for drying cake and does not cause drying unevenness. <P>SOLUTION: The equipment for dehydrating and drying sludge is provided with a pair of press membranes 52 and 52 and filter cloths 51 and 51 between a pair of adjacent filter plates 54 and 54, forms a filter chamber consisting of the press membranes 52 and 52 and the filter cloths 51 and 51 by tightening the filter plates 54 and 54 by clamping devices and compresses the sludge in the filter chamber from both sides. Passages 53a for the hot water are formed between the filter plates 54 and 54 and the press membranes 52 and 52 and membranes having a high thermal conductivity of 0.35 to 1.00 Wxm<SP>-1</SP>xK<SP>-1</SP>are used as the press membranes 52 and 52. Mesh-like materials 53 having a thickness ≥1 mm are arranged in the passages 53a for the hot water between the filter plates 54 and 54 and the press membranes 52 and 52 to uniformly disperse the hot water. Also, the hot water generated in a hot water generator 31 is circulated and a back pressure valve 33 is disposed on the outlet side of the filter chamber of the circulating route for the hot water. <P>COPYRIGHT: (C)2004,JPO

Description

ろ過工程は無加温ろ過を採用し、圧搾工程は加温圧搾と減圧乾燥とを採用し、乾燥工程は加温しつつ減圧する乾燥工程に統一している。原料の汚泥濃度は２０ｇ／Ｌと、同条件の汚泥を使用している。ここで、圧搾膜の熱伝導率は、従来例１においては０．２３Ｗ・ｍ^−１・Ｋ^−１であるのに対して、本発明の例１及び例２では圧搾膜の熱伝導率が０．６８Ｗ・ｍ^−１・Ｋ^−１と高いものを用いている。また、圧搾工程における圧搾圧力は、従来例１及び本発明の例１では、０．５ＭＰａを採用し、本発明の例２では１．５ＭＰａを採用している。
【００２６】
そして、最終的なケーキ含水率をいずれも３５％として実験した結果、従来例１では乾燥時間が２．１７ｈ（時間）であり、ろ過速度が０．２５ｋｇ・ｍ^−２・ｈ^−１となるのに対して、本発明の例１では乾燥時間が０．８３ｈ（時間）と大幅に短縮され、ろ過速度が０．３９ｋｇ・ｍ^−２・ｈ^−１となった。また、本発明の例２では、上述したように圧搾圧力を１．５ＭＰａとした結果、乾燥時間が０．５０ｈ（時間）と更に短縮され、ろ過速度が０．４５ｋｇ・ｍ^−２・ｈ^−１となった。
【００２７】
上記実験結果から、圧搾膜熱伝導率が乾燥時間の長短に大きく影響していることが分かる。図４は、この脱水乾燥装置に熱伝導率の異なる圧搾膜を取り付け、本発明の例２と同様な条件で実験した結果である。横軸には圧搾膜の熱伝導率を示し、縦軸にはケーキ含水率が３５％になるろ過速度を示している。この実験結果から、熱伝導率が０．３５Ｗ・ｍ^−１・Ｋ^−１以上で、大きなろ過速度が得られることが示されている。
【００２８】
表２は、従来の加圧圧搾脱水工程（従来例２）と、本発明の脱水乾燥工程（例３）とを比較した実験結果である。
【表２】

【００２９】
従来例２では、ろ過工程、圧搾工程共に無加温の状態で行い、本発明の例３では、ろ過工程を加温ろ過、圧搾工程を加温圧搾で実施した。原料としては、濃度２０ｇ／Ｌの同条件の汚泥を使用している。また、従来例２では、ろ過及び圧搾時の温度を２０℃として、圧搾時間０．８０ｈ（時間）でケーキ含水率６０％となり、ろ過速度０．４６ｋｇ・ｍ^−２・ｈ^−１となった。これに対して、本発明の例３では、ろ過及び圧搾時の温度を８０℃とした結果、圧搾時間０．５０ｈ（時間）でケーキ含水率６０％が得られ、ろ過速度０．５３ｋｇ・ｍ^−２・ｈ^−１となった。この表２に示す実験結果においても、本発明の脱水乾燥装置による工程においては、圧搾時間が大幅に低減し、全体としての全工程時間が低減し、これにより全体としてのろ過速度が向上していることが分かる。
【００３０】
また、従来例１と従来例２の脱水乾燥処理後のケーキを観察すると、ろ室周辺部と中心部とでは乾燥度合いに差が見られた。これに対し、本発明の例１〜例３では、得られたケーキの乾燥度合いに差が見られなかった。この効果の差は、ろ板と圧搾膜との間の温水通路に網目状物を配置して、これにより温水通路の均一性を確保すると共に、ろ布と圧搾膜との間に溝または突起を設け、これにより真空通路を確保して減圧処理の均一性を確保したことに基因していると考えられる。
【００３１】
尚、上記実施例は、本発明の好ましい実施例の一形態を述べたに過ぎず、本発明の趣旨を逸脱することなく、種々の実施例をとることが可能なことは勿論である。
【００３２】
【発明の効果】
上述したように本発明によれば、脱水乾燥対象の汚泥の加温に十分な熱伝導率を有する圧搾膜を用い、ろ室周辺において温水や減圧環境が均一に分布する構造を備えることで、ケーキの乾燥時間が短く且つ乾燥ムラが生じない汚泥の脱水乾燥装置が得られる。
【図面の簡単な説明】
【図１】本発明の実施形態の汚泥の脱水乾燥装置を示すブロック図である。
【図２】図１に示す脱水乾燥装置の要部の（ａ）断面図であり、（ｂ）平面図であり、（ｃ）全体構成を示す断面図である。
【図３】汚泥の脱水乾燥処理を示すフロー図である。
【図４】圧搾膜の熱伝導率とろ過速度との関係を示す実験結果のグラフである。
【符号の説明】
１１　　脱水乾燥機
１２　　汚泥供給ポンプ
１３　　汚泥供給ライン
２１　　センターブローライン
２３　　センターブロー排泥ライン
３１　　温水ユニット
３２　　温水循環ポンプ
３３　　背圧弁
３５　　温水循環ライン
３７　　真空ポンプ
３８　　凝縮槽
５１　　ろ布
５２　　圧搾膜
５２ａ　　突起または溝
５２ｂ　　真空吸引路
５３　　網目状物
５３ａ　　温水通路
５４　　ろ板[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dewatering and drying apparatus for sludge, and more particularly to sludge which is heated and pressurized to dewater sludge discharged from water and sewage equipment, rural settlement drainage equipment, human waste treatment equipment, industrial wastewater treatment equipment, etc., and dried under reduced pressure. And a dehydration drying apparatus.
[0002]
[Prior art]
Conventionally, in order to dewater and dry sludge, it is necessary to install a dewatering device and a drying device in each case, and the initial cost is large, and a great deal of labor is required for maintenance.
Further, there is known a method in which hot water is used as a pressing medium of a pressing press dehydrator and the outside of the filter cloth is depressurized, thereby heating and pressing the sludge and simultaneously drying under reduced pressure. However, in this apparatus, the thermal conductivity of the pressed membrane is low, and the distribution of hot water flow rate between the filter plate and the pressed membrane and the degree of decompression between the pressed membrane and the filter cloth are not uniform in some places. There are problems such as long drying unevenness.
[0003]
[Problems to be solved by the invention]
The present invention solves the above problems, has a pressed film having a thermal conductivity sufficient for heating the sludge, has a structure in which the flow rate of the hot water and the degree of vacuum are uniformly distributed, the drying time of the cake is short, and the drying is uneven. It is an object of the present invention to provide a sludge dewatering / drying apparatus in which no sludge is generated.
[0004]
[Means for Solving the Problems]
The sludge dewatering and drying apparatus of the present invention provides a pair of compressed membranes and a filter cloth between a pair of adjacent filter plates, and forms a filter chamber made of the compressed membrane and the filter cloth by tightening the filter plates with a tightening device. In a sludge dewatering and drying apparatus for squeezing the sludge in the filter chamber from both sides, a hot water passage is formed between the filter plate and the squeezed membrane, and the squeezed membrane has a thermal conductivity of 0.35 W · m ⁻ A film having a high thermal conductivity of from ¹ · K ⁻¹ to 1.00 W · m ⁻¹ · K ⁻¹ is used.
[0005]
In addition, a mesh material having a thickness of 1 mm or more is arranged in the hot water passage between the filter plate and the compressed membrane, and the hot water is uniformly dispersed on the entire surface of the hot water passage between the filter plate and the compressed membrane. It is preferable to make it. Further, it is preferable that hot water generated by a hot water generator is circulated in the hot water passage, and a back pressure valve and a bypass valve are arranged on the outlet side of the filter chamber of the hot water circulation path.
[0006]
Thereby, the hot water is uniformly dispersed in the hot water passage facing the filter chamber between the filter plate and the compression membrane. Then, when the sludge is heated and pressed, heat can be uniformly and efficiently applied to the sludge to be pressed by the pressed film having high thermal conductivity. Therefore, the heating, pressing and drying of the sludge is promoted, and a cake having a required moisture content can be produced in a short time. Here, the hot water can be uniformly dispersed in the hot water passage by a mesh material of 1 mm or more and 5 mm or less disposed in the hot water passage between the filter plate and the compression membrane. Further, by arranging the back pressure valve and the bypass valve in the circulation path of the hot water, the pressure of the hot water can be adjusted, whereby the heating and squeezing and heating and drying conditions of the sludge can be quickly adjusted.
[0007]
Further, the pressing membrane is provided with a groove or a projection for discharging a filtrate having a groove depth or a projection height of 3 mm or more and 10 mm or less between the filter cloth and the filter cloth. Further, a vacuum generator is provided, and the vacuum generator is started simultaneously with the squeezing by the hot water, and the sludge is heated, squeezed, dewatered and dried under reduced pressure by setting the gap between the squeezed membrane and the filter cloth to a reduced pressure atmosphere. Can be.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0009]
FIG. 1 schematically shows a sludge treatment system including a sludge dewatering and drying apparatus of the present invention. The dehydration dryer 11 is a device that performs dehydration drying of sludge. Inside, a pair of compressed membranes and a filter cloth are provided between a pair of adjacent filter plates, and the sludge in the filter chamber composed of the compressed membrane and the filter cloth is squeezed from both sides by tightening the filter plate with a fastening device. , A device for dehydrating and drying sludge. Sludge (slurry) to be dehydrated and dried is supplied to the dehydration dryer 11 from a slurry supply line 13 via a supply valve 15 by a slurry supply pump 12. Then, the sludge is dewatered and squeezed and dried by the dehydration dryer 11 to form a cake having a required moisture content, and is taken out from the dehydration dryer.
[0010]
Hot water is supplied to the sludge dryer 11, and the hot water promotes dehydration and drying of the sludge. Hot water is produced in the hot water unit 31 and is introduced into the header pipe 17 of the dehydration dryer 11 from the hot water circulation line 35 by the hot water circulation pump 32. The hot water used for dehydration and drying of the sludge in the dehydration dryer 11 is returned from the header pipe 18 to the hot water unit 31 by the hot water circulation line 35. As described above, the hot water circulates between the hot water unit 31 and the dehydration dryer 11, and the back pressure valve 33 and the bypass valve 34 are arranged on the outlet side of the dehydration dryer 11. Therefore, by adjusting the back pressure valve 33 and switching to the bypass valve 34, the flow rate of the circulating hot water and the pressure of the hot water in the dehydrating dryer can be quickly adjusted.
[0011]
In addition, vacuum suction is used for dehydration and drying of sludge in the dehydration dryer 11. Therefore, the vacuum pump 37 and the condensing tank 38 are provided, and the space between the filter cloth and the compressed membrane is set to a reduced pressure atmosphere, thereby promoting the dehydration and drying of the sludge inside the filter cloth. In addition, the vacuum pump 37 is activated simultaneously with the pressing step, and the pressure between the pressed membrane and the filter cloth is reduced to thereby heat, compress and dehydrate the sludge in the filter cloth, and also to dry under reduced pressure.
[0012]
The center blow air is supplied to the dehydration dryer 11 by the center blow line 21 and is discharged from the center blow sludge discharge line 23 together with the sludge that has not been dewatered. An air valve 22 is connected to the center blow line 21, and a mud discharge valve 24 is connected to the center blow mud discharge line 23.
[0013]
The hot water unit 31 supplies hot water as a compression medium and a heating medium, and keeps the temperature of the hot water at 70 ° C to 95 ° C. As the hot water unit 31, various heat sources such as a fuel such as electric power or petroleum, a hot water boiler using combustion exhaust gas, a steam drain, and a fuel cell drainage can be used. The hot water circulation pump 32 is preferably capable of applying a pressure of 0.5 MPa or more to the compressed film in the dehydration dryer 11. The filtrate line and the vacuum line connected to the dehydrator / dryer 11 are switched by the switching valves 1 and 2, and the condensing tank 38 and the vacuum pump 37 are connected to the vacuum line as described above. Cooling water circulates through the condensing tank 38. Here, the ultimate vacuum degree of the vacuum pump 37 is preferably 7 kPa or less.
[0014]
FIG. 2 shows a configuration example of a main part in a sludge dewatering / drying machine. As shown in the overall configuration example of FIG. 2C, a pair of compressed membranes 52, 52 and a filter cloth 51, 51 are arranged between a pair of adjacent filter plates 54, 54. Sludge to be dehydrated and dried is introduced into the filter cloths 51, 51, plates 56, 57 are tightened from both sides by a not-shown tightening device, and a pair of filter plates 54, 54 are tightened from both sides. A filter chamber is formed in 51. As shown in FIGS. 2 (a) and 2 (b), a mesh 53 having a thickness of 1 mm or more is arranged between the filter plate 54 and the pressed film 52, and is provided between the filter plate 54 and the pressed film 52. The passage 53a through which the hot water flows uniformly is secured.
[0015]
As the mesh 53, a mesh made of a heat-resistant and corrosion-resistant material having a wire diameter of 0.5 mm or more can be used. As the material, polyethylene, polypropylene, Teflon, stainless steel, or the like is preferable. The thickness of the mesh 53 is preferably 1 mm or more, and if it is 5 mm or more, there is a problem that the volume of the filter chamber is reduced.
[0016]
Here, a film having a high thermal conductivity of at least 0.35 W · m ⁻¹ · K ⁻¹ is used as the compressed film 52. As such a compression film, a film obtained by mixing 5 v / v% to 15 v / v% of carbon graphite with a polyurethane resin can be used. Thereby, the heat of the hot water flowing through the hot water passage can be quickly supplied to the sludge in the filter room, and the heat supply to the sludge in the filter room can be uniformly performed. However, 1.00 W · m ⁻¹ · K ⁻¹ or more has low strength and is not practical. The thermal conductivity of a normal polypropylene resin is about 0.1 W · m ⁻¹ · k ⁻¹ , and that of a crosslinked polyethylene resin is about 0.38 W · m ⁻¹ · K ⁻¹ .
[0017]
A groove or projection 52a for discharging filtrate is provided on the filter cloth 51 side of the compressed film 52, and the depth of the groove or the height of the projection is preferably 3 mm or more and 10 mm or less, and a circle having a width of 2 to 6 mm. It has a columnar or rectangular shape, and in the case of a rectangular shape, when the length becomes long, the concave portion becomes a groove. Here, when the depth of the groove or the height of the projection is 10 mm or more, the amount of heat conduction decreases, and the same effect as when a resin having low heat conductivity is used is obtained.
Thereby, it is possible to uniformly secure the vacuum suction path 52b in the gap between the compressed film 52 and the filter cloth 51. In addition, as a material of the filter plate, the mesh-like material, and the filter cloth, a commonly used material can be used as long as the material can withstand a greenhouse at 70 ° C. to 95 ° C.
[0018]
Next, an outline of the dewatering and drying process of the sludge by the dewatering and drying device will be described. As shown in FIG. 3, a basic sludge dewatering and drying step includes a filtration step, a pressing step, a center blow, and a drying step.
[0019]
The filtration step includes non-heated filtration and heated filtration. The compression step includes heated compression, heated compression and reduced-pressure drying, and the drying step includes heated drying and reduced-pressure drying. Optimal dehydration and drying can be performed by selecting components according to the properties of the sludge to be dehydrated and dried.
[0020]
The non-heating filtration is a filtration step for operating only the sludge supply system, and is a step in which the introduced sludge is naturally filtered by the filter cloth 54. The warm filtration is a filtration step that operates a mud supply system and a hot water system. In this case, hot water is supplied to a hot water passage between the compression membrane 52 and the filter plate 54 by a hot water circulation line. In this dehydration drier 11, a passage 53 a through which hot water flows uniformly is secured by the mesh-like material 53 provided between the filter plate 54 and the pressed film 52. Since the compression membrane 52 is made of a material having a high thermal conductivity and the hot water passage is secured by the mesh 53, the heat of the hot water is efficiently and evenly distributed, so that the heat of the hot water can be reduced by the filter cloth 51, It is transmitted to the sludge to be dried in 51.
[0021]
The heating and pressing is a pressing step of pressing the sludge while heating the sludge while operating the hot water system. In addition, the drying under reduced pressure is a pressing step of performing pressing under a reduced pressure atmosphere while operating a vacuum system. In these squeezing steps, it is preferable that the hot water circulates through the hot water circulation line 35 through the back pressure valve 33, and the back pressure valve 33 gradually raises the hot water pressure near the filter chamber from a low pressure to a predetermined pressure. Thereby, favorable heating and pressing can be performed.
[0022]
The drying step is a step of performing heating with hot water and drying under reduced pressure by operation of a vacuum device, and operates both the hot water system and the vacuum system. At this time, the hot water is preferably circulated through the bypass valve 34.
[0023]
As described above, the sludge dewatering and drying apparatus of the present invention uses a material having a high thermal conductivity for the compression membrane, arranges a mesh material in the passage of the warm water, and allows the warm water to flow uniformly in the passage near the filter chamber. Has become. In addition, a back pressure valve is provided in the circulation path of the hot water, so that the pressure of the hot water flowing on the back side of the compression membrane can be adjusted. This makes it possible to efficiently and uniformly transfer the heat of the hot water to the sludge (cake) to be dewatered and dried.
[0024]
Table 1 is for explaining the effect of the sludge dewatering and drying apparatus of the present invention, and is an experimental result comparing a conventional dewatering and drying step with the dewatering and drying step of the present invention.
[0025]
[Table 1]

The filtration step employs unheated filtration, the compression step employs heated compression and reduced-pressure drying, and the drying step is a unified drying step in which heating is performed and the pressure is reduced. The sludge concentration of the raw material is 20 g / L, and the sludge under the same conditions is used. Here, the thermal conductivity of the compressed film is 0.23 W · m ⁻¹ · K ⁻¹ in Conventional Example 1, whereas the thermal conductivity of the compressed film is 1 in Examples 1 and 2 of the present invention. A material as high as 0.68 W · m ⁻¹ · K ⁻¹ is used. The compression pressure in the compression step is 0.5 MPa in Conventional Example 1 and Example 1 of the present invention, and 1.5 MPa in Example 2 of the present invention.
[0026]
Then, as a result of an experiment in which the final cake moisture content was 35%, the drying time was 2.17 h (hour) and the filtration rate was 0.25 kg · m ⁻² · h ⁻¹ in Conventional Example 1. On the other hand, in Example 1 of the present invention, the drying time was significantly reduced to 0.83 h (hour), and the filtration rate was 0.39 kg · m ⁻² · h ⁻¹ . In Example 2 of the present invention, as described above, the pressing pressure was set to 1.5 MPa. As a result, the drying time was further reduced to 0.50 h (hour), and the filtration speed was 0.45 kg · m ⁻² · h ^−. It became ¹ .
[0027]
From the above experimental results, it can be seen that the thermal conductivity of the pressed film greatly affects the length of the drying time. FIG. 4 shows the results of an experiment conducted under the same conditions as in Example 2 of the present invention, in which pressed membranes having different thermal conductivities were attached to the dehydrating and drying apparatus. The horizontal axis shows the thermal conductivity of the pressed membrane, and the vertical axis shows the filtration rate at which the cake moisture content becomes 35%. The experimental results show that a high filtration rate can be obtained when the thermal conductivity is 0.35 W · m ⁻¹ · K ⁻¹ or more.
[0028]
Table 2 shows the results of an experiment comparing the conventional pressure-squeezing dehydration step (conventional example 2) with the dehydration-drying step (example 3) of the present invention.
[Table 2]

[0029]
In Conventional Example 2, both the filtration step and the pressing step were performed without heating. In Example 3 of the present invention, the filtering step was performed by hot filtration, and the pressing step was performed by hot pressing. As raw material, sludge having a concentration of 20 g / L under the same conditions is used. Further, in Conventional Example 2, the temperature during filtration and pressing was 20 ° C., and the pressing time was 0.80 h (hour), the water content of the cake was 60%, and the filtering speed was 0.46 kg · m ⁻² · h ⁻¹ . . On the other hand, in Example 3 of the present invention, as a result of setting the temperature during filtration and pressing to 80 ° C., a cake moisture content of 60% was obtained in a pressing time of 0.50 h (hour), and a filtration rate of 0.53 kg · m ⁻² · h ⁻¹ . Also in the experimental results shown in Table 2, in the process using the dehydrating and drying apparatus of the present invention, the pressing time is greatly reduced, the entire process time is reduced as a whole, and the overall filtration speed is improved. I understand that there is.
[0030]
In addition, when the cakes after the dehydration and drying treatments of Conventional Example 1 and Conventional Example 2 were observed, a difference was found in the degree of drying between the periphery and the center of the filter chamber. On the other hand, in Examples 1 to 3 of the present invention, no difference was observed in the degree of drying of the obtained cake. The difference in this effect is due to the arrangement of meshes in the hot water passage between the filter plate and the pressed membrane, thereby ensuring the uniformity of the hot water passage and the grooves or projections between the filter cloth and the pressed membrane. It is considered that this is due to the fact that the vacuum passage was secured to ensure the uniformity of the decompression process.
[0031]
It should be noted that the above-described embodiment is merely an example of a preferred embodiment of the present invention, and it is needless to say that various embodiments can be adopted without departing from the spirit of the present invention.
[0032]
【The invention's effect】
As described above, according to the present invention, by using a pressed membrane having a thermal conductivity sufficient for heating the sludge to be dehydrated and dried, by providing a structure in which hot water and a reduced pressure environment are uniformly distributed around the filter chamber, Thus, a sludge dewatering and drying apparatus in which the cake drying time is short and drying unevenness does not occur is obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an apparatus for dehydrating and drying sludge according to an embodiment of the present invention.
FIG. 2 is a sectional view (a) of a main part of the dehydrating and drying apparatus shown in FIG. 1, (b) a plan view, and (c) a sectional view showing the entire configuration.
FIG. 3 is a flowchart showing a dewatering and drying process for sludge.
FIG. 4 is a graph of an experimental result showing a relationship between a thermal conductivity of a compression membrane and a filtration rate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Dehydration dryer 12 Sludge supply pump 13 Sludge supply line 21 Center blow line 23 Center blow sludge discharge line 31 Hot water unit 32 Hot water circulation pump 33 Back pressure valve 35 Hot water circulation line 37 Vacuum pump 38 Condenser tank 51 Filter cloth 52 Compressed membrane 52a Projection Or groove 52b Vacuum suction path 53 Mesh 53a Hot water path 54 Filter plate

Claims (5)

A pair of compressed membranes and a filter cloth are provided between a pair of adjacent filter plates, and a filter chamber made of the compressed membrane and the filter cloth is formed by tightening the filter plate with a fastening device, and the sludge in the filter chamber is compressed from both sides. Sludge dewatering and drying equipment,
A hot water passage is formed between the filter plate and the pressed film, and the pressed film has a thermal conductivity of 0.35 W · m ⁻¹ · K ⁻¹ or more and 1.00 W · m ⁻¹ · K ^−1. An apparatus for dehydrating and drying sludge, using a membrane having the following high thermal conductivity. The sludge according to claim 1, wherein a mesh having a thickness of 1 mm or more is arranged in the hot water passage between the filter plate and the compression membrane, so that the hot water is uniformly dispersed. Dehydration drying equipment. The sludge according to claim 1, wherein hot water generated by a hot water generator is circulated in the hot water passage, and a back pressure valve and a bypass valve are disposed on an outlet side of the filter chamber in a circulation path of the hot water. Dehydration drying equipment. 2. A groove or a projection for discharging a filtrate having a groove depth or a projection height of 3 mm or more and 10 mm or less is provided between the compression membrane and the filter cloth. A sludge dewatering and drying apparatus as described in the above. The sludge dehydration / drying apparatus according to claim 1, further comprising a vacuum generator, wherein the vacuum generator is activated simultaneously with the pressing by the hot water, and the sludge is heated, pressed and dehydrated and dried under reduced pressure.

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