JPS5982996A - Drying method of hydrous material - Google Patents

Abstract

PURPOSE:To dry efficiently the dehydrated cake of sludge, etc. by transferring the heat retained in the air discharging from a blower to a hydrous material in a drying stage to evaporate water, and supplying the air discharging from the drying stage to an aeration stage such as treatment of waste water. CONSTITUTION:The dehydrated cake 6 which is discharged from a mechanical dehydration stage 5 for excess sludge 4 and is lumped or granulated to about several-cm grain size is supplied to a drying stage 7 provided with a packed part 7' for dehydrated cake. The air 9 discharging from a blower 8 for aeration is supplied directly into the stage 7 and the air 10 releasing from said stage is supplied to an air diffusion part 3 to aerate the inside of an aeration tank 2. The temp. of the air 9 of the blower 8 increases to 70-80 deg.C if the depth of the water in the part 3 is about 5m as is evident from the theory of adiabatic compression of gas. The heat energy that the air 9 possesses is effectively utilized for the air to be penetrated through the dehydrated cake in this method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for drying a water-containing material such as a sludge dewatered cake.

Generally, when organic wastewater such as sewage and human waste is treated by a biological treatment process such as an activated sludge method, an aeration blower 2 is used to supply oxygen to an aeration tank 22 as shown in FIG.
8 will be installed.

Conventionally, the function of this dark air blower 28 was simply warm air 1*2.
It only performs the single function of supplying oxygen to 2,
To this day, this has remained a matter of course without any question raised.

On the other hand, organic sludge such as sewage sludge, raw sludge, and surplus/I:i mud 24 is dehydrated in various dehydrators 25 to become a dehydrated cake 26 with a water content of around 80%, but if left as is, it will be incinerated due to its high water content. Since it is very inconvenient to dispose of it by composting, landfilling, etc., it is necessary to dry it with various types of dryers 27. However, the reality is that the conventional dryer 27 consumes a large amount of fuel, resulting in an energy-intensive process. Moreover, strong foul-smelling exhaust gas 67 is discharged from this drying process, and a large amount of equipment is required in the deodorizing process 35 of the foul-smelling waste 67.
There is no doubt that the current state of our industry is that it requires high costs and maintenance costs.

In FIG. 1, 21 is organic wastewater, 62 is a settling basin, 66 is returned sludge, 64 is treated water, 66 is a tune for the dryer 27, and 38 is deodorizing gas.

The present invention is based on the technical idea that the energy possessed by the aerated air discharged from the aeration blower, which has conventionally been used only for supplying oxygen to the aeration tank, can be utilized for drying water-containing materials such as sludge dewatering cake in a new embodiment. based on (things,
The heat retained in the blower discharge air is directly or indirectly transferred to the water-containing material in the drying process, and the moisture in the water-containing material is evaporated, and the air discharged from the drying process is used for wastewater treatment or organic/I This is a drying method for water-containing materials, which is characterized by supplying and using mud for aeration.

Next, one embodiment of the present invention will be described with reference to FIG.
The dehydrated cake 6 discharged from the mechanical dewatering process 5 (belt press, filter press, screw press, etc.) of the excess sludge 4 is made into lumps or granules with a particle size of several cm, and then the dehydrated cake filling section 7' Drying process 7 with
supply to.

However, it is not clear from the compression theory that the discharge air 9 of the aeration blower 8 is directly vented into the drying process 7 and the exhaust air 10 is supplied to the aeration section 6 to aerate the inside of the aeration tank 2. When the water depth of the air diffuser 6 is approximately 5 m, the temperature of the discharged air 9 rises to 70 to 80°C.

The thermal energy of this discharged air has not been used effectively in the past, but in this embodiment it is effectively used for drying the dehydrated cake 6 through ventilation.

As a result, the aeration tank lower 8 performs the important combined functions of supplying oxygen to the aeration tank 2 and drying the dehydrated cake 6.

As a result, energy for drying the dehydrated cake B is substantially unnecessary, and the energy saving effect is significant. In addition, conventional dryers required a deodorizing process for malodorous exhaust gas, but in the present invention, dry exhaust gas is automatically supplied to the aeration tank 2, and the huge amount of microorganisms present in the aeration tank 2 biologically removes the odor. Another important effect is that no special deodorizing process is required since the product is deodorized.

Furthermore, in the conventional dryer, a step of removing dust from the dry exhaust gas is essential, but in the present invention, the exhaust air 10 (・j) containing dust is supplied to the aeration tank 2, so the aeration tank 2 is Since it functions as a single-glaze dust collector, there is no need for a special dust removal process.For this purpose, the diameter of the discharge air hole of the aeration part 6 is set to several wn or more as much as possible, and the dust collects as much as possible. It is highly desirable to prevent this from happening.

Incidentally, although a single filling section 7' may be provided, if a plurality of filling sections 7' are provided as shown in FIG. 3 and the dried material 11 is taken out after the dehydrated cake 6 is dried, the discharge air? If the valve is operated so as to switch and send the liquid to another filling section 7', operational management becomes extremely easy.

In addition, it is preferable that the water content of the dehydrated cake 6 supplied to the filling section 7' be kept below the liquid limit.If the dehydrated cake has a moisture content higher than this and is easy to flow, it may cause stickiness to the wall surface of the filling section 7' or fluidity. This is not very preferable because the airflow resistance of the filling portion 7' becomes high and it becomes difficult to take out the dried material 11.

The aeration tank 2 is used not only for the biological treatment process of organic wastewater 1 but also for aerobic digestion of surplus activated sludge, and a re-aeration tank or P' for returned sludge. Of course, it may also be an aeration tank for oxidizing reducing ions such as '+ ions.

When organic wastewater 1 contains ammonia nitrogen,
If aeration tank 2 not only removes BOD but also nitrates ammonia nitrogen, ammonia nitrogen 1 to 9
Since approximately 4.5 k of oxygen is required to oxidize BOD to NO3, the amount of air to be supplied to the aeration tank 2 is larger than when only BOD removal is performed, and as a result, the filling section 7
In ', the extremely important effect that the amount of water evaporated from the dehydrated cake 6 can be significantly increased is exhibited.

The structure of the filling part 7' is most preferably as shown in FIG. 3, but any other structure can be used, such as a structure that vents in the lateral direction or a fluidized bed type. It can be anything that the Soviet Union can directly contact.

In addition, a fluidized bed or a fixed bed may be used as a direct aeration method, and an indirect heating method may be used as a contact method other than aeration.

In FIG. 2, 12 is a settling tank, 13 is return sludge, and 14 is treated water.

As described above, the present invention provides a method for supplying specific air, that is, discharge air of an aeration blower for the purpose of wastewater treatment or supplying air to an aeration tank for organic sludge, to a dehydrated cake filling section, and for filling the dehydrated cake. The most important point is that the air flowing out from the tank is supplied into the aeration tank rather than being discarded outside the system.

The industrially important effects of the present invention are as follows.

■ It is possible to dry water-containing materials such as sludge dewatering cake in an energy-saving manner without using any fuel such as heavy oil.

■ Special equipment and maintenance costs for removing dust and malodorous components from dry exhaust gas are not required at all.

■ Aeration blower - By directly venting the discharge air into the drying material filling section, a heat exchanger is not required, and the heat capacity coefficient of the drying material filling section is 2000 to 4000 K0a'
/,,=°C, which is extremely low (because it is thick, the volume of the filling part can be small. This result.

Equipment costs for drying are significantly lower.

■ Since the moisture content of the dried material can be easily reduced to 40% or less, it has the surprising effect of allowing self-combustion when incinerated, and making it possible to recover energy by using a boiler incinerator. This fact truly demonstrates the superiority of the effect of the present invention when compared with the conventional process in which a large amount of auxiliary fuel is consumed and drying is incinerated.

Example Night Waste Treatment A certain human waste processing factory with a production capacity of 100 KJ processes human waste using a biological nitrification and denitrification process (referred to in the art as a low dilution two-stage activated sludge process). In this process, the aeration depth of the aeration tank for nitrogen is 5 rn, and the discharge amount by the blower is io o Nnty/B.
Air from IH is sent to the aeration tank.

On the other hand, the flocculated sludge generated from the process of coagulating and settling the surplus activated/Fi mud from the above process and the process treated water with sulfate sand (the total amount of sludge generated from both processes is 859.DS/E7- Ll) was dehydrated using a fully automatic filter press with a pressing mechanism (filtration pressure 5 kfa, pressing pressure 15
1 (9 f/cd) As a result, a dehydrated cake with a water content of 68 cm was obtained.

This dehydrated cake was crushed into particles with a particle size of about 1 to 2 cm using a crusher such as a meat chopper, and then packed into the filling section of the flow of the present invention (Fig. 2). Discharge air (temperature 65~80℃) at superficial velocity 08~
1. Aeration was carried out at o'rrL4°, and desired air discharged from the filling section was supplied to the aeration tank for nitrification. The air discharged from the filling section contained dust and exhibited an odor with an odor concentration of 1000 to 150 mouths, but the air discharged from the water surface of the aeration tank contained extremely little odor and dust. After aeration for one day, the dehydrated cake was taken out from the filling section and the moisture content was measured. As a result, the moisture content was extremely low at 15 to 20 degrees, and the calorific value was high at 3000 to 71//. Not only was it extremely easy to self-combust, but the steam could also be recovered, and there was a surplus of steam left over that could be used for heating and bathing in the administration building.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet showing a conventional organic wastewater treatment process, FIG. 2 is a flow sheet showing an embodiment of the present invention, and FIG. 3 is a flow sheet showing a drying process for a dehydrated cake. 1. Organic wastewater, 2. Aeration tank, 6. Diffusion section, 4.
... Surplus sludge, 5... Mechanical dewatering process, 6... Dehydrated cake, 7... Drying process, 7'... Filling section, 8... Aeration blower 19... Discharge air, 10 ...Exhaust air, 11...Dry matter, 12...Sedimentation tank, 16...Return sludge, 14...Treated water. ! Applicant for license: Ebara Infilco Co., Ltd. Procedural Amendments 1939 & Kakuji August 25th Patent Office Attendant Kazuo Wakasugi 1・1 Indication of Soup 1982 Patent Application No. 192371 2・Issued”0
Name Organic sludge treatment method 3, person making the correction (Relationship with Patent applicant I) Mr. R, (fJ+:) (040) Ebara Infilco Co., Ltd. 4, Representative) Seijin 5. Date of amendment order. 6. Number of inventions increased by amendment. 1. Title of invention: Organic sludge processing power method 2. Claims: Local law. 2. The method according to claim 1, wherein the drying step is performed by directly blowing blower discharge air through the packed bed of the dehydrated cake. 4. The method according to claim 1, which treats nitrogen-containing wastewater and biologically nitrates ammonia in the wastewater by the aeration. 4. The drying step removes moisture as the dehydrated cake. 6. Detailed Description of the Invention The present invention relates to a method for drying a dewatered cake of organic sludge.Generally When organic wastewater such as sewage and human waste is treated using a biological treatment process such as the activated sludge method, the method shown in Figure 1 is 5.
An aeration blower 28 for supplying oxygen to the VC aeration tank 22 is installed. Conventionally, the function of this aeration blower 28 has been solely that of supplying oxygen to the aeration tank 22, and this has been regarded as a matter of course without any question being asked. On the other hand, organic sludge such as sewage sludge, raw sludge, and surplus sludge 24 is dehydrated in various dehydrators 25 and becomes a dehydrated cake 26 with a water content of around 80%. Since it is very inconvenient to dispose of the waste by recycling, landfilling, etc., it is necessary to dry it using various types of dryers 27. However, the conventional dryer 27 consumes multiple needles of fuel,
The reality is that it is an energy-consuming process. Furthermore, the present state of the industry is such that a strongly foul-smelling exhaust gas 67 is discharged from this drying process, and the deodorizing process 65 of the foul-smelling exhaust gas 67 requires a large amount of equipment and maintenance costs. In FIG. 1, 21 is organic wastewater, 32 is a settling tank, 36 is return sludge, 64 is treated water, 36 is oil for the dryer 27, and 38 is deodorizing gas. The technical idea of the present invention is to use the energy of the discharged air of an aeration blower, which has conventionally been used only for supplying oxygen to an aeration tank, to dry water-containing materials such as sludge dewatering cake using a new actual MMM method. A drying process is installed in the middle of the piping route that connects the aeration process discharge side and the aeration part of the wastewater treatment process or organic sludge treatment process, and in this drying process, the organic sludge becomes a dehydrated cake. The retained heat of the blower discharge air is directly or indirectly transferred to dry it, and the cooled blower discharge air is supplied to the aeration section of the wastewater treatment process or organic sludge treatment process for aeration. This is a method for treating organic sludge characterized by the use of organic sludge. Next, one embodiment of the present invention will be described with reference to FIG.
is provided, and the dehydrated cake 6 discharged from the mechanical dewatering process 5 (belt press, filter press, screw press, etc.) of the excess sludge 4 is made into lumps or granules with a particle size of approximately α, and the dehydrated cake filling section 7' The drying process 7 is provided with a drying process. Therefore, the air 9 discharged from the aeration blower 8 is transferred to the drying process Z.
The discharged air 9 is brought into direct contact with the dehydrated cake 6, and the discharged air 10 is supplied to the aeration part 6 button and used for aeration in the aeration tank 2. As is clear from the theory of adiabatic compression of gas, the temperature of the discharged air 9 of the aeration blower 8 rises to 70 to 80°C when the water depth of the aeration section B is about 5 m. Conventionally, the thermal energy of this discharged air 9 has not been utilized effectively, but in this embodiment, the dehydrated cake 60
Use effectively for ventilation drying. This allows the aeration blower 8
It performs multiple functions such as supplying oxygen to the aeration 41!2 and drying the dehydrated cake 6. As a result, the energy required for drying the dehydrated cake 6 is substantially reduced to 4 times, and the energy saving effect is significant. In addition, conventional dryers require a deodorizing process for foul-smelling exhaust gas, but the dried exhaust gas, that is, the exhaust air 10, is automatically supplied to the heating/air tank 2, and the huge waterfall of living things that exist in the aeration tank 2 is removed. Another important effect is that no special deodorizing process is required because the odor is removed biologically. Furthermore, in conventional dryers, the process of removing dust from dry exhaust gas is essential, but since the exhaust air 10 containing dust is not supplied to the aeration tank 2, the aeration tank 2 is used as a kind of dust collector. This function eliminates the need for a special dust removal process. For this purpose, the diameter of the discharge air hole of the air diffuser 6 should be set as large as possible to a few degrees or more to prevent clogging of the duct (this is extremely preferable. Note that the filling section 7' may be one tower). However, as shown in FIG.
If the dried material 11 is not taken out after the drying process, operational management becomes extremely easy if the valve is operated so that the discharged air 9 is switched and sent to another filling section 7'. In addition, it is preferable that the water content of the dehydrated cake 6 supplied to the filling part 7' is kept below the liquid limit.
Since it becomes sticky and fluid, the ventilation resistance of the filling part 7' becomes high and it becomes difficult to take out the dried material 11, which is not very preferable. The aeration tank 2 is used not only for the biological treatment process of organic wastewater 1 but also for the remainder 1.
] An aeration tank for aerobic digestion of activated sludge, a re-aeration tank for returned sludge, or an aeration tank for oxidation of reducing ions such as Fe ions may also be used. When organic wastewater 1 contains ammoniacal nitrogen,
If the aeration tank 2 not only removes BOD but also nitrates ammonia nitrogen, it takes approximately 4°S to oxidize 1q of ammonia nitrogen to NO8. of oxygen is required, the amount of air to be supplied to the aeration tank 2 is larger than when only BOD removal is performed, and as a result, the amount of water evaporated from the dehydrated/r-kg in the filling section 7' also increases significantly. This has the extremely important effect of being able to do so. In this way, according to the above embodiment, not only is there no need for any special equipment and maintenance costs for removing dust and malodorous components in the dry exhaust gas, but also the discharge air from the aeration blower can be directly connected to the drying material. Since ventilation is provided inside the chamber, the number of heat exchangers is 4, and the heat capacity coefficient of the drying material filling section is 2000 to 4000 Kcal/,,=,
hr, °C, which is extremely large, so the volume of the filling part may be small. As a result, the equipment cost for drying is significantly reduced. The structure of the filling section 7' shown in FIG. 3 is most suitable, but any other structure can be used, such as a structure that vents in the lateral direction or a fluidized bed type. Any material that can be directly contacted by the air 9 may be used. Note that the direct air flow method may be performed using a fluidized bed or a fixed bed, and as a drying method other than aeration, an indirect heating method is used. As described above, the present invention provides a method for supplying air discharged from an aeration blower for the purpose of wastewater treatment or for supplying air to aeration of organic sludge to the upper stage of drying a dehydrated cake, and for drying the dehydrated cake. The most important point is that the air discharged from the process is not disposed of outside the yarn, but is instead supplied into the aeration tank. The industrially important effects of the present invention are as follows. Q) It is possible to dry water-containing materials such as sludge dewatering cake in an energy-saving manner without using any fuel such as heavy oil. ■ Since the moisture content of dry matter can be easily reduced to 40% or less, it not only becomes possible to self-combust when incinerated, but also has the surprising effect of making it possible to recover energy by using a boiler incinerator. The fact truly demonstrates the superiority of the effect of the present invention when compared with the conventional process which consumes a large amount of auxiliary fuel and uses dry incineration.Example Human waste throughput 100 K4//IE At a certain human waste treatment factory, human waste is treated using a biological nitrification and denitrification process (referred to in the field as the low dilution two-stage activated sludge process).In this process, the depth of the aeration tank for nitrification is 5 m. The discharge amount is 100N77//mln by the blower.
air is sent to the aeration tank. On the other hand, the flocculated sludge generated from the process of coagulating and precipitating the excess activated sludge from the above process and the water treated in the process using sulfuric acid (the total amount of sludge generated from both processes is 8°51°) ) was dehydrated using a fully automatic filter press with a squeezing mechanism (filtration pressure: 5"y f7..1°; squeezing pressure: 15 Df/, 1). As a result, a dehydrated cake with a moisture content of 68% was obtained. The particles crushed into particles with a particle size of 1 to 2 cfn using a crusher such as a meat chopper are packed into the filling section of the flow of the present invention (Fig. 2, 1). 80℃) at a superficial velocity of 0.8
~1.0shi agency. The air discharged from the filling section was supplied to the aeration tank for nitrification. The air discharged from the filling section contained dust and exhibited an odor with an odor concentration of 1000 to 500, but the air discharged from the water surface of the aeration tank had very little odor and dust. When the dehydrated cake was taken out from the filling section and the moisture content was measured, the moisture content was extremely low at 15-20%, and the heat generation rate was 3000KCalA, 1. , Ds, so it was not only extremely easy to self-combust in the Boiler 51 incinerator, but also to recover Subuno, and even when it was used for the 1V room and bath in the Kanmisaki building, there was still surplus steam left. 4. Brief description of the drawings Fig. 1 is a flow sheet showing a conventional organic wastewater treatment process, Fig. 2 is a flow sheet showing an embodiment of the present invention, and Fig. 3 is a flow sheet showing the drying process of a dehydrated cake. It is a flow sheet. 1...Organic wastewater, 2...Aeration tank, 6...Aeration section, 4...Excess sludge, 5...Mechanical dewatering process, 6...Dehydrated cake, 7...Drying process , 7'... Filling part, 8.
... Aeration blower - 19 ... Discharge air, 10 ... Discharge air, 11 ... Dry matter, 12 ... Sedimentation tank, 16 ...
・Return sludge, 14...treated water. Patent Applicant Ebara Infilco Co., Ltd. Representative Patent Attorney Sen 1) Minoru Procedural Amendment Letter November 8, 1980 Commissioner of the Patent Office Mr. Kazuo Wakasugi 1 Indication of Case 1981 Patent Application No. 192371 2 Issued”0 Name Organic sludge treatment method 3, Person making the amendment (Relationship with 'l Patent applicant address (residence) Name) (040) Ebara Infilco Corporation 4, Agent 5, Date of amendment order Voluntary 6. Number of inventions increased by amendment 7. Subject of amendment Full text of the specification - 8. Contents of amendment As attached, overnight U embryo 9 - a299e (s) Amended specification ■ 1 Name of invention Method for treating organic sludge 2. Scope of Claims] A drying process is provided in the middle of a piping route connecting the aeration blower discharge side and the aeration part of the wastewater treatment process or the organic sludge treatment process, and the organic sludge is dehydrated in the drying process. The cake is dried by directly or indirectly transferring the retained heat of the blower discharge air to the cake, and the cooled blower discharge air is supplied to the aeration section of the waste water treatment process or the organic sludge treatment process. A method for treating organic sludge, characterized in that it is used for aeration. 2. Claim 1, wherein the drying step is performed by directly aerating blower discharge air through the packed bed of the dehydrated cake. 3. The method according to claim 1, wherein the wastewater treatment step is to treat ammonia nitrogen-containing wastewater, and biologically nitrify ammonia in the wastewater by the aeration. 4. The method according to claim 2, wherein the drying step treats the dehydrated cake having a water content of 85q6 or less. 3. Detailed description of the invention The present invention This invention relates to a method for drying a dehydrated cake of organic sludge.Generally, when organic wastewater such as sewage and human waste is treated by a biological treatment process such as an activated sludge method, oxygen is supplied to an aeration tank 22 as shown in Fig. 1. Aeration blower 2
8 will be installed. Conventionally, the function of this aeration blower 28 has been solely that of supplying oxygen to the aeration tank 22, and this has been considered a commonplace and has remained unquestioned to this day. On the other hand, organic sludge such as sewage sludge, raw sludge, and surplus sludge 24 is dehydrated in various dehydrators 25 and becomes a dehydrated cake 26 with a moisture content of around 8 degrees. Because the emergency button is inconvenient for nano-disposal, it is necessary to dry with various types of dryers 27. However, the reality is that the conventional dryer 27 consumes a large amount of fuel, resulting in an energy-intensive process. Furthermore, it is undeniable that the current state of the industry is that intensely foul-smelling exhaust gas 37 is discharged from this drying process, and that the deodorizing process 35 of the foul-smelling exhaust gas 37 requires a large amount of equipment and maintenance costs. In FIG. 1, 21 is organic wastewater, 32 is a settling tank, 33 is return sludge, 64 is treated water, 66 is oil for the dryer 27, and 68 is deodorizing gas. The present invention (□-i) claims that the energy of the air discharged from the aeration blower, which was conventionally used only for supplying oxygen to the aeration tank, is used in a new embodiment to dry water-containing materials such as sludge dewatering cake. This is based on technical research, and a drying process is installed in the middle of the piping route that connects the aeration blower discharge side and the wastewater treatment process (1) and the aeration part of the organic sludge treatment process. The retained heat of the blower discharge air is directly or indirectly transferred to the dehydrated organic sludge cake to dry it, and the cooled blower discharge air is transferred to the aeration section of the wastewater treatment process or organic sludge treatment process. This is a method for treating organic sludge, which is characterized in that it is supplied to a sludge and used for aeration. It is used in meanings including flocculated sedimentation sludge and flocculated floating sludge.Next, to explain one embodiment of the present invention with reference to FIG. 2, the water surface in the aeration tank 2 of organic wastewater 1 Air diffuser 3 below
is provided, and the dewatered cake 6 discharged from the mechanical dewatering machine 65 (belt press, filter press, sufu') of the surplus sludge 4 is transformed into lumps or granules with a particle size of several trn. The dried cake is supplied to a drying step 7 equipped with a dehydrated cake filling section 7'. 1. The air 9 discharged from the aeration blower 8 is brought into direct contact with the dehydrated cake 6 into the drying and pumping rod 7.11. The discharged air 1o is supplied to the air diffuser 3,
Used for aeration in 1 bottle and 2 tanks. In addition, a so-called oxygen aeration method is used in which air is supplied by a combination noser to an adsorption tower that adsorbs and removes N2 gas and CO2 gas other than oxygen in the air using a molecular sieve to produce high-concentration oxygen gas, which is used in the aeration process. Since compression heat is generated in a part of the air compressor, it is sufficient to use this compression heat to dry the sludge and then supply the air whose temperature has been lowered to the adsorption tower for generating high-concentration oxygen gas. Needless to say. In other words, the object of the present invention can be achieved using either air or oxygen for aeration. As is clear from the theory of adiabatic compression of gas, the temperature of the discharged air 9 of the aeration blower 8 rises to 70 to 80°C when the water depth of the aeration section B is about 5 m. Conventionally, the thermal energy of the discharged air 9 has not been utilized effectively at all, but in this embodiment, it is effectively utilized for ventilation drying of the dehydrated cake B. In addition to this, the aeration blower 8
As a result, the energy for drying the dehydrated cake 6 is virtually unnecessary, and the energy saving effect is significant. There is. Moreover, conventional dryers require a deodorizing process for foul-smelling exhaust gas, but the dry exhaust gas, that is, the exhaust air 10, is automatically supplied to the aeration tank 2. It also has the important effect that no special deodorizing process is required since it is chemically deodorized. Furthermore, in conventional dryers, a process of removing dust from dry exhaust gas is essential, but since the exhaust air 10 containing dust is supplied to the aeration tank 2, the aeration tank 2 is a kind of dust collector. Since it functions as a vacuum cleaner, there is no need for a special dust removal process. For this purpose, it is extremely preferable to make the diameter of the discharge air holes of the air diffuser 3 as large as possible, to a diameter of several or more, to prevent clogging with dust. Incidentally, the filling section 7' may be one column, but if a plurality of packing sections 7' are provided as shown in FIG. If the pulp operation is performed so that the pulp is switched and sent to another filling section 7', operational management becomes extremely easy. In addition, it is preferable that the water content of the dehydrated cake 6 supplied to the filling part 7' be kept at a moisture content of 85% or less. If the dehydrated cake has a higher moisture content than this and is easy to flow, it may cause stickiness on the wall surface of the filling part 7' or flow. This is not very preferable because the airflow resistance of the filling part 7' becomes high and it becomes difficult to take out the dried material 11. The aeration tank 2 is not only an aeration tank for biological treatment of organic wastewater 1, but also an aeration tank for aerobic digestion of surplus activated sludge, a re-aeration tank for returned sludge, or an aeration tank for oxidation of reducing ions such as FG ions. Of course it's fine. When the organic wastewater 1 contains ammonia nitrogen, if the aeration tank 2 not only removes BOD but also nitrates the ammonia nitrogen, the ammonia nitrogen 1
Since approximately 4.5 kg of oxygen is required to oxidize 1 kg of NO3K, the amount of air to be supplied to the aeration tank 2 is larger than when only BOI removal is performed. The extremely important effect is that the amount of water evaporated from the cake 6 can also be significantly increased. In this way, according to the above embodiment, not only is there no need for any special equipment or maintenance costs for removing dust and malodorous components in dry exhaust gas, but also the air discharged from the aeration blower is directly used to fill the material to be dried. Since the heat exchanger is not required because the inside of the drying section is ventilated, the heat capacity coefficient of the drying material filling section is 2000 to 4000 ktnl/lr?・hr
・Since the temperature is extremely large (°C), the volume of the filling part may be small. As a result, the equipment cost for drying is significantly reduced. The structure of the filling part 7' is most preferably as shown in FIG. 3, but any other structure can be used, such as a structure with horizontal ventilation or a fluidized bed type. Any type of material may be used as long as the discharged air 9 can come into direct contact with it. In addition, a fluidized bed or a fixed bed may be used as a direct aeration method, and an indirect heating method may be used as a drying method other than aeration. Moreover, the aeration blower as used in the present invention means an air compressor that supplies oxygen-containing gas to the aeration process. In FIG. 2, 12 is a settling tank, 13 is return sludge, and 14 is treated water. As described above, the present invention provides a method for supplying specific air, the discharge air of an aeration blower for the purpose of wastewater treatment or supplying air to an aeration tank for organic sludge, to a dewatered cake drying process.
The most important point is that the air discharged from the drying process is not discarded outside the system, but is instead supplied into the aeration tank. The industrially important effects of the present invention are as follows. ■ It is possible to dry water-containing materials such as sludge dewatering cake in an energy-saving manner without using any fuel such as heavy oil. ■ Since the moisture content of dry matter can be easily reduced to less than 40%, it has the surprising effect that not only self-combustion is possible in the case of incineration, but also energy recovery is possible by using a boiler incinerator. This fact truly demonstrates the superiority of the effect of the present invention when compared with the conventional process in which a large amount of auxiliary fuel is consumed and drying is incinerated. Next, examples of the present invention will be shown. Example 1 Human waste treatment At a certain human waste processing factory, human waste is treated by a biological nitrification and denitrification process (referred to in the art as a low dilution two-stage activated sludge process). In this process, the aeration water depth of the aeration tank for nitrification is 5 m.
The discharge amount is 100Ni/ml by the blower.
n air is sent to the aeration tank. On the other hand, flocculated sludge generated from the process of coagulating and settling surplus activated sludge from the above process and cough process treated water with sulfuric acid soil (the total amount of sludge generated from both processes is 8.5 k)
g-DS/kl human waste) was dehydrated using a fully automatic filter press with a squeezing mechanism (filtration pressure 5 kgf/c4. Squeezing pressure 15 kg, If'/l:rI). As a result, a dehydrated cookie with a water content of 68 cm was obtained. Obtained. This dehydrated cake is crushed to a particle size of about 1 to 2α using a crusher such as a meat chopper, and then packed into the filling section of the flow of the present invention (Fig. 2).
The discharge air (temperature 65-80°C) has a superficial velocity of 0.8-1.
Ventilation was performed at 0 m/see, and the air discharged from the filling section was supplied to the aeration tank for nitrification. The air discharged from the filling section contains dust and has an odor concentration of 1.
However, the air discharged from the water surface of the aeration tank had very little odor and dust. After aeration for one day, the dehydrated cake was taken out from the filling section and the moisture content was measured.The moisture content was extremely low at 15-20%.
Also, the fever is tri, 3000 kd/kgφDS
Because of its high temperature, it was not only extremely easy to combust it in a boiler incinerator, but also to recover the steam, which was used for heating and bathing in the administration building, and there was still surplus steam left over. Example 2 Surplus activated f4 generated from the same amount of human waste and treatment process in the human waste treatment plant described in Example 1: Sludge and coagulated sludge were dehydrated using a centrifugal dehydrator instead of a filter press, resulting in a dehydrated cake containing water. The rate was 81% (cationic polymer addition rate 1.5% to Dry 5 solid). This dehydrated cake was granulated to a size of 1 cm x 2 cm and filled into the filling section of the flow of the present invention (FIG. 2). The filling capacity of the dehydrated cake was 10-. High-discharge air from an aeration blower (at 75° C.) was aerated into this at a superficial velocity of 08 m4, and the discharged air was supplied to an aeration tank for nitrification. After one day of aeration, the moisture content of the dried material was 68%, and it could be self-combusted in a multi-stage furnace. Next, the centrifugal force of the centrifugal dehydrator was lowered to intentionally reduce the water content to 8.
When a 6-inch dehydrated cake was obtained and an attempt was made to dry it using the method of the present invention, the dehydrated cake was highly sticky and the water content ratio was extremely large at 6.14 kgH20/kg @ DS, making granulation impossible. In addition, the dehydrated cakes adhered to each other in the packed bed and formed large lumps, making it impossible to aerate. Although aeration was carried out under these conditions, the moisture content of the dehydrated cake after a day of aeration was highly uneven, ranging from 78 to 83.
Self-combustion (was impossible. Figure 3 is a flow sheet showing the drying process of dehydrated cake. 1...Organic wastewater, 2...Aeration tank, 3...Aeration section,
4... Excess sludge, 5... Mechanical dewatering process, 6 - Dehydrated cake, 7... Drying process, 7'... Filling section, 8 - Aeration blower 19... Discharge air, 10... Exhaust air, 1
1... Dry matter, 12... Sedimentation tank, 16... Returned sludge,
14... Treated water. LF)・Applicant Ebara Infilco Co., Ltd. Attorney 1000 1) Minoru

Claims (1)

[Claims] 1. Directly or indirectly transfers the retained heat of the blower discharge air to the water-containing material in the drying process to evaporate the water content of the water-containing material, and at the same time, the exhaust air from the drying process A method for drying a water-containing material, characterized by supplying the water to an aeration process of wastewater treatment or organic sludge treatment and using it for aeration. 2. The method according to claim 1, wherein the drying step is performed by directly blowing air discharged from a blower through the packed bed of the water-containing material. 6. The method according to claim 1, wherein the wastewater treatment step is to treat ammonia nitrogen-containing wastewater, and the ammonia in the wastewater is biologically nitrified in the aeration step. 4. The method according to claim 2, wherein the drying step treats a hydrated material whose water content is below the liquid limit.