JPS60114398A - Cooling tower for industrial water provided with function for treating activated sludge - Google Patents

Abstract

PURPOSE:To improve the effect of cleaning up sewage by microorganisms by providing packed material layers for aeration of activated sludge behind the air passage of paked material layers for cooling water provided in a column and providing a water mist remover in the part behind the air passage thereof. CONSTITUTION:An air release fan 18 is actuated when a motor 17 is started and the external air induced through an aperture 8 into a column body 1 is subjected to a heat exchange with the hot water flowing down in packed material layers 2 for cooling water while the air passes through the inside of the layers 2. The air thus heated to hot air passes through a water mist remover 7. The water mists in the hot air are thus removed and the satd. moist air flows through a space 14 into packed material layers 10 for aeration of activated sludge. The aeration of the activated sludge is accomplished in the layers 10. The air entering the layers 10 is a large amt. of the moist air and when such air contacts with the cold activated sludge water, substantial oxygen and heat are supplied to the activated sludge water.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention provides a cooling tower for industrial water, in which, in addition to the cooling function of cooling water, the discharged air is used to aerate activated sludge treated water. This article relates to industrial water cooling towers with additional functions.

(Prior art) In factories equipped with activated sludge treatment equipment for organic sewage discharged from production processes, such as chemical factories and food factories, industrial water used as cooling water in the production process is circulated through a cooling tower. Often used.

In industrial water cooling towers, cooling water (warm water) whose temperature has risen from being used to cool external equipment is introduced into the cooling tower, and is spread over the cooling water packing layer while it flows down inside the layer. In this method, external air is induced to pass through this filler layer to exchange heat with the hot water, and the warm air whose temperature has increased due to this heat exchange is released into the atmosphere as it is.
There is a large loss of thermal energy here.

On the other hand, the conventional method of aeration of activated sludge water in activated sludge water treatment involves installing an aeration device in the aeration tank.
Blow in air (oxygen) to mix inflow sewage and activated sludge.
Air aeration method with stirring, contact aeration method where aerobic microorganisms are attached to and multiply on the filter material filled in the aeration tank, air (oxygen) is blown into this, and the inflowing wastewater is circulated and brought into contact with it, and the aeration tank water surface A rotary impeller is installed on top to suck up the mixed water of inflowing sewage and activated sludge and scatter it in a thin film.
There are mechanical surface aeration methods that make contact with air, and all of these require a large amount of power.

The purpose of aeration in the activated sludge method is to mix and stir inflowing sewage and activated sludge while supplying oxygen from the atmosphere, allowing microorganisms to adsorb pollutants (organic substances) in the sewage, oxidatively decompose them, and purify them. The temperature range suitable for purifying wastewater is 20°C to 30°C.

However, during the aeration process, heat is constantly dissipated, which causes the water temperature to drop, and especially in the winter when the outside air temperature is low, the activity of microorganisms decreases and it takes a long time to purify the wastewater.

(Object of the invention) This invention has been made focusing on the above points,
In the cooling water filling layer of an industrial water cooling tower, the saturated humid air that is discharged after exchanging heat with the hot water flowing down in the layer is guided to the activated sludge water aeration packed layer installed in the same tower. By bringing the activated sludge water flowing down from above the bed into gas-liquid contact in the filler layer, the activated sludge water is heated at the same time as aeration, and the air cooled by heat exchange with the activated sludge water is heated. The waste heat is discharged to the outside air by a fan, and this waste heat energy is used effectively, and sufficient oxygen is supplied to the waste water so that the sewage purification effect of microorganisms is always maintained under suitable conditions. The aim is to provide an industrial water cooling tower that will greatly contribute to reducing the cost of wastewater treatment equipment using the activated sludge method.

(Structure of the Invention) This invention provides a packing material layer for activated sludge water aeration at the rear of the water cooling packing material layer provided in the tower through which air passes,
A water droplet remover is provided at the rear of the air passage, and the activated sludge water is aerated in the activated sludge water aeration filling material layer using heated and humidified saturated moist air that passes through the water cooling filling material layer. The summary is as follows.

Embodiments of the present invention will be described below based on the drawings.

In the figure, 1 is a tower main body, and 2 is a cooling water filling layer provided within this tower main body, which is divided into steps in the downward direction of -L. 3 is a hot water distribution tank arranged on the cooling water filler layer and connected to a hot water supply pipe 4 connected to external equipment, and the bottom surface is capable of uniformly sprinkling water over the entire surface of the filler tank 2. It is equipped with a large number of water spray nozzles 5. Reference numeral 6 indicates a cooling water receiving tank provided under the layer of packing material N2, 7 indicates a water droplet remover provided at the rear part of the packing material layer 2 through which air passes, and 8 corresponds to the cooling water filled layer 2 on the side wall of the tower body 1. This is an opening that is opened to allow outside air to flow in.
It is equipped with a looper 9. 10 is a packing material layer for activated sludge water aeration provided in the tower body adjacent to the cooling water filling material layer 2, and is of a type that adopts a tiered packing material etc. that has low air resistance and can prevent scattering of flowing sewage. Each shelf has a removable drawer system for easy cleaning.

11 is opened and arranged in the uppermost layer of this filler N10,
Activated sludge water supply pipe connected to external sewage treatment equipment, 12 an activated sludge water receiving tank provided under the filler layer 10, 13 a water droplet remover provided at the rear of the filler layer 10 through which air passes, 14
15 is a space provided between the cooling water filler layer 2 and the activated sludge aeration filler layer 10, 15 is a space provided behind the air passage of the activated sludge aeration filler layer 10, and 16 is this space. An exhaust port 15 is opened at the top, and an exhaust fan 18 connected to a motor 17 is disposed at the exhaust port 16 .

In addition, in the figure, reference numeral 19 is an inspection door provided to allow access to and exit from the spaces 14 and 15, respectively.

(Function) In the above configuration, the exhaust fan is activated by starting the motor 17, and the outside air that is drawn into the tower body l through the opening 8 first passes through the cooling water filling layer 2. While passing through, heat exchange is performed with the hot water flowing down the layer, and the air becomes warm air, which passes through the water droplet remover 7. Water droplets in the warm air are removed by passing through the water droplet remover 7, and enter the activated sludge water aeration filler layer 10 as saturated moist air through the space 14, where the activated sludge water is aerated. It is something that will be carried out.

However, this activated sludge water aeration filler layer 10
The incoming air is a large amount of saturated moist air that has been heated and humidified, and when this comes into contact with the cold activated sludge water, sufficient oxygen is supplied to the activated sludge water and at the same time it stimulates the activity of microorganisms. Sufficient heat is supplied for maintenance, which serves to support efficient oxidative decomposition of BOD components in wastewater.

In addition, by adopting a format for the aeration filler layer 10 in which the activated sludge water flows down sequentially with less water droplet scattering, it is possible to prevent the activated sludge water from mixing with industrial water and contaminating the inside of the tower due to sludge adhesion. Since water droplets flying along with the air flow from the cooling water filling layer 2 can be captured, the water droplet remover 7 behind the cooling water filling layer 2 can be omitted to prevent an increase in air resistance. You can also do that.

(Effects of the Invention) The present invention has the following effects due to the above-described structural action.

(1) Regarding the function of supplying oxygen necessary for biologically decomposing and removing organic substances contained in activated sludge water, the amount of air discharged from the cooling tower is enormous, and ordinary aeration is not sufficient. The amount of air is several tens of times higher than that of the conventional method, and it has a sufficient oxygen supply function.

(2) The gas-liquid contact function sprays activated sludge water onto the filler layer from above and allows it to fall naturally, in order to bring about effective contact between organic substances in activated sludge water and the group of organisms that decompose and remove them. It is fully demonstrated by the mixing and stirring action during the process.

(3) With the conventional activated sludge method, in winter when the water temperature is between 4°C and 9°C, it takes more than 10 hours of aeration time to achieve a BOD removal rate of 90%, but with this invention, The exhaust heat from the cooling tower is effectively used, and the water temperature can be maintained at 20°C or higher through gas-liquid contact between the activated sludge water and the heated hot air.
OD removal rate is obtained.

(4) Conventionally, the design criteria for the activated sludge method was based on the treatment capacity in winter, but by adopting the device of this invention, the treatment capacity in winter can be approximately doubled, for example, as mentioned above. This means that the design conditions remain the same throughout the seasons, resulting in stable operation management.

(5) By increasing the sewage treatment capacity in winter, it is not only possible to reduce the capacity of the aeration tank, but also by placing the cooling tower of this invention close to the sewage treatment equipment, the entire equipment can be made compact. Therefore, it is possible to significantly reduce equipment construction costs.

(6) The original functions and maintenance of the cooling tower are well-maintained, and the structure takes into account the prevention of water droplet scattering by adopting tiered filling material for the activated sludge water aeration filling layer. In addition, there is no problem in dealing with the adhesion of organic substances in activated sludge water as the filler is removably drawn out and has a structure that allows easy cleaning.

(7) Regarding operation and maintenance costs, the air volume and waste heat energy released into the atmosphere by cooling tower fans should be effectively used, and the aeration filler layer should be of a type with low air resistance, such as a tray type. By using the filler layer, only a slight increase in fan power is required, which is significantly less than the rotational power of conventional air diffusion blowers or mechanical aeration systems. Furthermore, in winter in cold regions,
In some cases, steam is blown into the aeration tank to raise the water temperature, but this is no longer necessary.

[Brief explanation of the drawing]

The drawings are configuration diagrams showing embodiments of the present invention. ■...Tower body, 2...Cooling water filling layer, 3...
Hot water distribution tank, 4... Hot water supply pipe, 5... Water nozzle, 6... Cooling water receiving tank, 7... Water droplet remover, 8...
・Opening 0 part, 9... Louver, 10... Filler layer for activated sludge water aeration, 11... Activated sludge water supply pipe, 12
...Activated sludge water receiving tank, 13... Water droplet remover, 14
．． 15...Space, 16...Exhaust port, 17...Motor, 18...Exhaust fan, 19...Inspection door. 1

Claims (1)

[Claims] A packing material layer for activated sludge water aeration is installed behind the water cooling packing material layer provided in the tower, and a water droplet remover is installed at the rear of the air passing through. An industrial water cooling tower equipped with an activated sludge processing function, characterized in that it is configured to aerate activated sludge water in a packing material layer for activated sludge water aeration using heated and humidified saturated moist air.