JPH05111700A - Method and device for drying treatment of activated sludge and the like - Google Patents

Abstract

PURPOSE:To provide the method and device for the drying treatment of activated sludge and the like which eliminates the troubles associated with the conventional methods and devices, is high in a drying treatment speed and treatment efficiency and produces decreased exhaust gases. CONSTITUTION:This method consists in agitating the activated sludge and the like while heating the same by a heat medium, thereby executing the drying treatment thereof in a container 1 kept in a vacuum state. This drying treatment device for the activated sludge and the like agitates the activated sludge and the like while overheating the activated sludge and the like by the heat medium in the container 1 kept in the vacuum state. (1) The device is required to have the container 1 for housing the activated sludge and the like and subjecting the activated sludge and the like to the drying treatment. (2) A heater 7 for supplying the heat medium is required to be provided in the container 1. (3) An agitating device 5 is provided to be provided in the container 1. (4) A vacuum device, such as vacuum pump 8, is required to be connected to the container 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for drying activated sludge, particularly activated sludge having a water content of 70% by weight or more (hereinafter referred to as sludge).

[0002]

2. Description of the Related Art Conventionally, the following methods have been provided for drying sludge having a water content of 70% by weight or more. a. A method in which hot air and sludge are brought into direct contact with each other and dried as in a rotary dryer, b. A method in which a heating medium is introduced into the inside like a drum dryer and the sludge attached to the surface of the rotating cylindrical drum is indirectly heated under atmospheric pressure, c. A method in which a jacket having a heating medium is provided inside the container, and the sludge inside the container is indirectly heated and stirred under atmospheric pressure.

[0003]

However, each of the above-mentioned conventional methods has the following drawbacks. a. The method of drying by directly contacting hot air and sludge like a rotary dryer is accompanied by a strong odor due to the vaporized components in the exhaust gas, and since it also contains a large amount of exhaust gas and dust, Release into the atmosphere causes secondary pollution. Therefore, it is necessary to install a deodorizing device and a dust collector, and the device becomes bulky, which is not economically preferable. b. Like a drum dryer, a heating medium is introduced inside and the sludge adhered to the surface of the rotating cylindrical drum is indirectly heated under atmospheric pressure. It is necessary to prevent contamination, and care must be taken when adding sludge. Further, due to the nature of the device, maintenance and management of the part to which sludge adheres is troublesome, and there is a disadvantage that it is not suitable for large-scale treatment. c. In addition, the method of indirectly heating and stirring the sludge inside the container under atmospheric pressure with a jacket having a heat medium inside the container is sludge-like when the temperature of the sludge reaches 100 ° C. And then violently adheres to the wall surface, which becomes a heat transfer resistance and significantly reduces the drying speed, and the load for stirring increases and the power rises, and in some cases it becomes impossible to operate, There is inconvenience. For this reason, an increase in the number of processes such as the use of a means for recycling a part of the dried product and mixing it with sludge to lower the water content at the inlet has been brought about. The present invention has been made in view of the above points, and an object thereof is to provide a method and an apparatus for drying activated sludge, which solve the above-mentioned inconvenience.

[0004]

In order to achieve the above object, the present invention provides a structure in which activated sludge is dried by stirring and drying with heating medium in a container in a vacuum state. Is a drying treatment apparatus for activated sludge which is agitated while being overheated by a heat medium in a container in a vacuum state, and is configured to have the following requirements. (1) A container for containing activated sludge and drying it is provided. (2) A heating device for supplying a heat medium to the container is provided. (3) A stirring device is provided in the container. (4) A vacuum device such as a vacuum pump is connected to the container.

[0005]

The sludge can be dried by agitating the sludge while heating it with a heat medium while stirring it. At this time, since the inside of the container is in a vacuum state, the temperature rise of the sludge is suppressed, sludge formation is prevented, and the sludge is prevented from adhering to the inner wall surface of the container.
It acts to accelerate the drying speed. In addition, the increase in stirring load is suppressed, the increase in power is also prevented, and the amount of exhaust gas is also suppressed. In the drying treatment device, sludge is put into a container. The sludge thrown into the container is heated by a heating medium supplied by a heating device and agitated by a stirring device. At this time, since a vacuum device such as a vacuum pump is connected to the container, the inside of the container can be in a vacuum state. Therefore, the sludge can be dried while being stirred in a vacuum container while being heated.

[0006]

The present invention will be described in detail below with reference to the illustrated embodiments. FIG. 1 is a schematic explanatory view showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a cylindrical container having a sludge charging port 2 through which sludge is charged into the container 1. The input port 2 is provided with an opening / closing lid 3 which is opened when the sludge is input and can be sealed and closed during the drying process.

A shaft 4 is rotatably provided at the center of the container 1 in the longitudinal direction, and a stirring blade 5 is attached to the shaft 4.
Are projected radially. A drive source (not shown) is connected to the shaft 4 so as to rotate, and the stirring blade 5 is rotated by rotating the shaft 4. The sludge thrown into the container 1 by the rotation of the stirring blade 5 is stirred.

A jacket 6 is provided on the outer surface of the container 1 so as to surround the container 1, and a heating device 7 is connected to the jacket 6 so that a heating medium such as steam is supplied. It has become. As a result, the sludge in the container 1 is indirectly heated by the heat medium.

Further, a vacuum device such as a vacuum pump 8 is connected to the container 1 via a condenser 9. Thereby, the inside of the container 1 can be in a vacuum state. In the figure, 10 is a discharge port provided in the container 1, 11 is a drain outlet of the jacket 6, and 12 is a drainage port of condensed water.

Then, the sludge is charged into the container 1 through the charging port 2 having the opening / closing lid 3 opened. When the sludge is added, the opening / closing lid 3 is closed. Since the stirring blade 5 is fixedly mounted on the shaft 4 and rotatably provided in the container 1, the sludge put into the container 1 can be stirred by rotating the stirring blade 5. Also, a jacket 6 is provided on the outer surface of the container 1.
Since the heating device 7 is connected to the jacket 6 to supply the heat medium, the sludge introduced into the container 1 supplies the heat medium from the heating device 7 to the jacket 6. Thus, the container 1 can be heated and indirectly heated. Furthermore, since a vacuum device, for example, a vacuum pump 8 is connected to the container 1, the inside of the container 1 can be in a vacuum state. Therefore, the sludge thrown into the container 1 can be dried by stirring while heating in the container 1 in a vacuum state.

When the sludge is heated and agitated under vacuum as described above, the temperature of the sludge does not rise. For example, absolute vacuum 1
Under 00 mmHg, the temperature of sludge rises only to 50 ~ 55 ℃. Therefore, since the sludge does not sludge and maintains the cake state, not only can the adhesion to the inner wall surface of the container and the stirring blades and the mutual adhesion of the sludges be suppressed, but also the adhesion will be naturally separated. , The drying speed is fast, and the drying process is speeded up. Further, if the adherence is suppressed without mudification, the stirring load does not increase and the operation can be continued with stable power. Incidentally, the experimental data obtained by drying the sludge under vacuum and atmospheric pressure is shown in FIG.
Shows the result under vacuum and B shows the result under atmospheric pressure. According to the experimental results shown in FIG. 2, under vacuum, sludge having a water content of 83% by weight was dried to about 2% by weight in 25 minutes, whereas under atmospheric pressure, it was about 61% by weight even in 30 minutes. Only processed to%.

[0012]

As described above, according to the present invention, the sludge is heated under vacuum while being agitated and dried, so that the temperature of the sludge does not rise and mudification can be prevented, and the inner wall surface of the vessel and the stirring blade can be prevented. It is possible to suppress the adhesion of water and the mutual adhesion of sludges. Therefore, the drying processing speed is high, the drying processing is speeded up, the stirring load is not increased, and the operation with stable power can be continued. Also, the amount of exhaust gas is reduced. Furthermore, since the sludge treatment temperature is low, the dried product can be used as a fertilizer, a soil modifier, etc. depending on the components.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing an embodiment of the present invention.

FIG. 2 is a graph showing the results of a drying treatment experiment of the present invention and a conventional example.

[Explanation of symbols]

 1 Container 2 Input Port 4 Shaft 5 Stirring Blade 6 Jacket 7 Heating Device 8 Vacuum Pump 9 Condenser

Claims (2)

[Claims] 1. A method of drying activated sludge, which comprises stirring and drying activated sludge while heating it with a heating medium in a vacuum vessel. 2. An apparatus for drying activated sludge, which agitates activated sludge in a vacuum vessel while heating it with a heat medium, and is provided with the following requirements. (1) A container for containing activated sludge and drying it is provided. (2) A heating device for supplying a heat medium to the container is provided. (3) A stirring device is provided in the container. (4) A vacuum device such as a vacuum pump is connected to the container.