JP2592356B2 - Organic sewage biological filtration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel biological filtration method and apparatus for purifying various kinds of organic wastewater, such as sewage, human waste, and industrial wastewater, at a high speed and at a high level with only a single treatment tank.

[0002]

2. Description of the Related Art Conventionally, an aerobic biological filtration device (Biological Aerated Filter, abbreviated as BAF) using a particulate mineral such as anthracite or activated carbon as a bioadhesive carrier has been known.

[0003] BAF has attracted great interest in recent years because it can perform biological treatment and filtration of SS at the same time using a particulate filter medium as a bioadhesive carrier. However, the following problems have become widespread. Is hindering.

[0004] In other words, high SS, high BOD raw water
When F is applied, the blocking of the filter medium proceeds rapidly, and a long-time biological filtration treatment cannot be performed. In this case, a sedimentation basin must be provided before BAF, and most of SS must be removed in advance by sedimentation. Therefore, the system becomes complicated, and the installation area and the construction cost increase. If the biological filter bed is clogged, the filter bed must be backwashed with treated water, but conventional BAF requires a washing cycle at least once a day, and a large amount of washing wastewater is generated. I will. In addition, there is a disadvantage that a large amount of treated water produced as a washing water must be consumed. Since the amount of biological support on the particulate filter medium is small, high-speed processing cannot be performed.
The filtration speed LV in the case of sewage treatment is only about 25 m / day. Therefore, a system and a device capable of further high-speed processing are strongly desired.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel technique which can completely solve the above-mentioned serious disadvantages of the conventional BAF. That is, high SS,
A new technology that eliminates the need for a sedimentation basin in front of the BAF even for high BOD raw water. There is little clogging of the filter bed,
New technology that can reduce consumption of washing water. Conventional B
A new technology that can perform advanced purification at a higher filtration speed than AF. The challenge is to establish

[0006]

DISCLOSURE OF THE INVENTION The present invention has been completed as a result of considering that the filter layer configuration of biological filtration crucially governs the performance of the biological filtration method (BAF) and studying the optimum filter layer configuration in detail. Things.

That is, the present invention is as described below and described, whereby the above-mentioned object can be solved. The fixed layer A made by filling a elastic porous granules in a bath provided, via the space portion to the upper portion of the fixed layer A, which fixed layer B formed by filling the elastic porous granules, Organic sewage is supplied from above the fixed bed B, and treated water is supplied to the fixed bed A.
Fixed layer A lower supply of the cleaning water and oxygen-containing gas into the bottom of the fixed layer B of the fixed layer A is taken out from the bottom
The washing frequency of the fixed layer B to be less than that of the fixed layer B.
Biological filtration apparatus of organic sewage, characterized in that it has deployed. The biological filtration apparatus for organic wastewater as described above, wherein the washing water supplied to the lower part of the fixed layer B is the organic wastewater.

According to the present invention, a fixed layer formed by filling an elastic porous granular material in a single tank is composed of a lower fixed layer A and an upper fixed layer B.
A two-layer structure, and a supply part for washing water is provided below each fixed layer, and a supply part for oxygen-containing gas for maintaining each fixed layer in an aerobic state is provided at an appropriate position. Microorganisms are supported, and the fixed layers A and B are formed as biological filter beds having different functions.

That is, in purifying organic sewage, the present invention first involves passing the organic sewage through a fixed layer B filled with elastic porous granules having excellent SS trapping performance and trapping amount as a biofouling filter medium. By microbial treatment of biologically removed BOD and the like contained in the organic sewage, and by physically filtering a pollutant component containing at least SS that can be physically filtered, filtered water with reduced SS is obtained. The filtered water is passed through a fixed layer A filled with a biofouling filter medium in which microorganisms are also adhered to the elastic porous granules to physically filter unfiltered SS and remove unfiltered B.
The biological treatment of OD components and the like purifies organic wastewater.

That is, the present invention relates to a fixed layer A and a fixed layer B.
Are kept aerobic and each functions as a biological filtration layer. In the present invention, however, the physical filtration function is mainly given priority over biological treatment in the fixed layer B to perform high-speed filtration. This is a structure that gives priority to biological treatment, and clarified filtered water can be obtained efficiently.

The details of the structure of the fixed layers A and B of the present invention are not limited.
It is preferably designed so as to obtain ５０50 mg / l or less. Further, the SS concentration of the final treatment liquid of the fixed layer A, B
The OD concentration is preferably 10 mg / l or less, and can be easily achieved.

Further, the filtration device LV of the present invention has a
High-speed filtration of 200 m / day is possible .

[0013] supply of the cleaning water and an oxygen-containing gas, fixed layer A, but are provided in the lower portion of each of the fixed layer B, since the fixed layer B is a layer of oxygen to maintain the aerobic,
Since it can be supplied from the fixed bed A, in particular the oxygen supply for this can be omitted. However, it is clear that it can be used for this purpose if desired.

It is preferable that the supply section of the oxygen-containing gas is also used as a supply section for washing the biological filter beds of the fixed beds A and B with air. Therefore,
The supply section of the oxygen-containing gas provided below the fixed layer B may be dedicated to cleaning. Further, the supply section of the oxygen-containing gas provided in the fixed layer A can serve both for maintaining the aerobic property and for the cleaning. However, it is preferable to separately provide the supply sections with their functions dedicated.

The supply section of the oxygen-containing gas and the cleaning water may be the same supply section, which has both functions, or may be independent, and various conventionally known devices are applied, and a plate-like, tubular, or block The shape and the like are general, and are installed below each fixed layer. Here, the lower part of the fixed layer has a meaning including the inside of the fixed layer. The lower portion of the fixed layer B is not particularly limited, but includes the above-mentioned space portion . Usually, the supply portion is provided below a member supporting the elastic porous granular material. Usually, it is reasonable to arrange the supply unit provided at the lower part of the fixed layer A, particularly for maintaining aerobicness, at the lower part in the fixed layer.

A known method can be used for washing each of the fixed layers A and B. For example, air washing, simultaneous air / water washing, water washing, and the like can be used. be able to. Further, the supply air amount, the water amount, and the like may be appropriately set. Since device to perform high-speed filtering of the present invention, since the fixed layer B is the physical filtration of SS from biological treatment is preferentially, faster rate of increase in filtration resistance than the fixed layer A, washed frequently than the fixed layer A Generally, the fixed layer A and the fixed layer B are washed independently (however, each fixed layer may be washed at the same time).

Further, the fixed layer B can be sufficiently washed even with the organic sewage as the liquid to be treated, and the filtered water can be used only with the fixed layer A. In addition, there is an effect that the amount of treated water can be increased without reducing the amount of treated water due to the use of the filtered treated water. In the apparatus of the present invention, the washing wastewater generation ratio (washing wastewater amount / total treated water amount) can be made 0.05 or less.

The means for draining the washing wastewater from the fixed layer A and / or the fixed layer B to the outside of the system may be arbitrarily selected, and any known means can be used. An outflow pipe and the like are provided on the tank wall in the space . It is preferable to provide the space because the fixed layer A can be easily washed.

In the present invention, the clarified filtered water flowing down from the fixed bed B to the fixed bed A and treated is obtained from the treated water outlet provided at the lower part of the tank. The structure of the treated water outlet is also known. There is no particular limitation, and the apparatus may be provided alone or may also be used as a supply unit for the oxygen-containing gas and / or the cleaning water, for example, a block structure.

The elastic porous granules used in the present invention are:
Although any shape, material, pore structure and the like can be applied, this is an important requirement for realizing high-speed filtration in the present invention, and it is preferable to select a form suitable for physical filtration and propagation of microorganisms. For example, there is a structure that has a continuous hole from the surface to the inside,
It can be manufactured by a known foaming method or the like.

The material of the elastic porous granular material is not particularly limited as long as it has the above properties, and known materials such as organic polymers and inorganic compounds can be used. Materials having elasticity and strength are preferred, and urethane resins and the like are particularly preferred.

For example, an elastic porous granular material such as a polyurethane foam is produced by foaming plastics such as urethane resin by a foaming method for producing open cells, and is used as it is or cut into a desired shape and size. .

The size of the elastic porous granular material is from 10 to 30.
mm, and the shape may be square, spherical, or various other shapes, but square is preferred. Its specific gravity is usually 0.8
About 1.2 is preferable.

The porosity of the elastic porous granular material is preferably 90% or more. The pore diameter, that is, the hole diameter is 1 to 4 m.
m, preferably in the range of 2-3 mm. The number of holes per 1 cm length is preferably 3 to 5.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a specific embodiment of the present invention will be described together with the operation of the present invention, but the present invention is not limited to this.

A fixed layer A2 filled with elastic porous granules (polyurethane foam or the like) is provided in the treatment tank 1. Below the fixed layer A, a support floor 3 is provided by any means such as a net, a perforated plate, a gravel layer, etc., to prevent outflow of the elastic porous granules (in the illustrated example, the net is the support floor 3). thing).

A fixed layer B5 is provided above the fixed layer A with a space 4 interposed therebetween. 6 is a support member (net etc.). As the filled granular material constituting the fixed layer B,
It is important to use elastic porous granular materials as in the fixed layer A.

In the middle or lower part of the fixed layer A, there is provided a supply part 8 of an oxygen-containing gas 7 necessary for the respiration of microorganisms carried inside the elastic porous granular material. Further, the fixed layer A
A water supply unit 9 for washing the filter bed and a gas supply unit 10 for washing the filter bed (air is usually used as a gas) are installed in the lower part of the column.

It is also important to provide a filter bed washing water supply unit 11 and a filter bed washing gas supply unit 12 (usually using air as a gas) below the fixed bed B. It is one of the important conditions of the invention.

Above the fixed layer B, an inflow portion 13 for organic wastewater (raw water) and a washing drainage outflow portion 14 are provided. Next, an outflow pipe 15 for biological filtration treatment water is provided below the fixed layer A,
The outflow pipe rises to near the upper interface 16 of the fixed layer B. Reference numeral 17 denotes a treatment water tank.

The above is the main structure of the present invention. Next, the operation of the present invention will be described. The sewage treatment will be described as an example.

The sewage (raw water) 10 is first supplied to the upper part of a porous member 18 such as a net, and after screening for large foreign substances (hair, fiber, rubber products, etc.) in the sewage, the treatment apparatus of the present invention is used. Is supplied to the upper part of the fixed layer B of the elastic porous granular material, and flows down in a downward flow.

Microorganisms are maintained at a high concentration in the pores 20 of the open cells as shown in FIG. 2 inside the elastic porous granular material 19 in the fixed layer B, and mainly for maintaining aerobicity. A respiratory action is performed by oxygen supplied from a supply unit 8 such as an oxygen-containing gas or a filter bed gas supply unit 10 or 12, and BOD in sewage is biologically removed.
At the same time, the SS in the sewage is filtered and captured in the water in the void 20 of the elastic porous granular material itself and the space between the granular materials.

Thereafter, the effluent from the fixed bed B flows downwardly into the fixed bed A via the space 4,
BOD and SS that could not be completely removed in the fixed layer B are removed to a high degree by biological filtration.

Microorganisms are held at a high density inside the elastic porous granular material constituting the fixed layer A as in FIG. 2 and oxygen supplied from the oxygen-containing gas supply unit 8 or the cleaning gas supply unit 10 is supplied. Causes the microorganisms to breathe.

As a result, in the fixed bed A, trace amounts of BOD and SS contained in the effluent from the fixed bed B are highly removed biophysicochemically, and both SS and BOD are 10 mg / day.
1 or less of clear treated water is obtained from the outlet pipe 15.

That is, the fixed layer B functions as the primary treated water, and the fixed layer A functions as the secondary or advanced processing function. The elastic porous granular material in the present invention has an extremely large porosity of 97% or more, and therefore has an extremely large capacity for capturing SS in sewage. As a result, the increase in filtration resistance due to the capture of SS is small, and even if sewage is directly introduced at a high filtration speed, the progress of clogging of the filter bed is extremely small.

In particular, most of the removal of SS in raw water (80
% Or more) progresses in the fixed bed B, so that the increase in filtration resistance of the fixed bed A, in other words, the degree of progress of the filter bed clogging is remarkably low.

Based on this finding, the present invention employs a method in which the cleaning times of the fixed layer A and the fixed layer B are staggered, and the frequency of cleaning the fixed layer A is significantly less than the frequency of cleaning the fixed layer B.

Further, it is possible to adopt a unique means in which raw water is supplied from the filter bed cleaning water supply section 11 as cleaning water for the fixed layer B, and treated water is used only for the cleaning water for the fixed layer A. By these two means, the consumption of treated water as washing water for the biological filter bed (the combination of the fixed bed A and the fixed bed B) could be significantly reduced.

The following method is effective for cleaning the filling layer B. First, the valve 21 of the outflow pipe 15 of the treated water is closed,
Raw water is supplied from the filter bed washing water supply unit 11, a large amount of air is supplied from the filter bed washing gas supply unit 12, and a strongly upward gas-liquid multiphase flow (slugging state) is given to the fixed bed B.
As a result, the SS and the proliferating microorganisms trapped in the fixed layer B are removed from the inside and the surface of the elastic porous granular material, and flow out of the system from the cleaning drainage outlet 14 to the cleaning drainage tank (not shown). It is led to. At this time, the large foreign matter trapped on the porous member 18 such as a net is also washed and removed, and
It flows out of the system from the outflow pipe provided in 4.

In this operation, the washing of the fixed layer B is completed in about 5 to 10 minutes. Thereafter, the valves 22 and 23 are closed, and the raw water is supplied again from above the fixed bed B. Next, the cleaning frequency of the fixed layer A is 1/5 of the cleaning frequency of the fixed layer B for the above-described reason.
Although the amount of the fixed layer can be greatly reduced to about 1/10, if the operation is continued for a long period of time, the filtration resistance of the fixed layer A part increases. Therefore, the fixed layer A is washed by the following procedure.

That is, the valve 21 is closed, air is supplied from the filter bed gas supply unit, and treated water is supplied from the filter bed cleaning water supply. A strong gas-liquid multiphase flow is generated in the fixed bed A. The SS and growing microorganisms trapped inside and on the surface of the elastic porous granular material are washed and removed. The washing drainage is caused to flow out of the system from the drain pipe 24. In addition, you may make it flow out from the outflow part 14.

After this operation is continued for a required time (about 5 to 6 minutes), the supply of the air from the gas supply unit 10 and the treatment water from the water supply unit 9 is stopped, and the processing can be resumed by opening the valve 21. Chino clear water comes out.

Next, the physical properties of the elastic porous granular material applied to the present invention will be described. In the present invention, the elastic porous granular material used is an open-cell type having a large pore diameter and a large porosity, for example, a granular piece of polyurethane foam having a cell number of 3 to 5 cells / cm (holes per cm). Number), and those having a particle size of 1 to 3 cm square are suitable. This is different in concept from a so-called sponge, and leaves only a sponge skeleton. The sponge has a fine hole and cannot be seen through the opposite side of the granular material, but the one used in the present invention has such a large hole that the opposite side can be seen through.

When a normal sponge is used, since the diameter of the hole of the sponge is small, microorganisms are fixed only on the surface of the sponge and cannot grow inside the sponge, so that the amount of microorganisms within the biological filtration diameter cannot be maintained at a high concentration. There are drawbacks. In addition, there is a disadvantage that dissolved oxygen cannot penetrate into the sponge and is anaerobic inside.

On the other hand, a skeleton-like polyurethane foam can aerobically maintain a high concentration of microorganisms therein as shown in FIG. 2 and is therefore very suitable for the practice of the present invention.
The layer height of the fixed layer B is preferably about 0.3 to 1.0 m. The reason is that about 90% of the raw water SS is 0.3-1.
Sufficiently removed with a layer pressure of about 0 m;
This is because if the layer height is too high, the required amount of cleaning water and the time required for cleaning increase, resulting in disadvantages.

The bed height of the fixed bed A may be experimentally determined according to the quality of raw water and the set filtration speed.
It may be about 2 m.

[0049]

[Effect of the Invention] Even when the raw water SS and the BOD have a high concentration, there is no need to provide a sedimentation basin before the BAF. Fixed layer B
Has a sedimentation basin replacement function. As a result of dividing the fixed layer A and the fixed layer B of the elastic porous granular material into two stages and increasing the frequency of cleaning the fixed layer B more than the frequency of cleaning the fixed layer A, the amount of generated wastewater per wash is reduced. It is easy to dispose and store the wastewater. The fixed layer B is washed with raw water without using treated water as the washing water for the fixed layer B.
Since only the cleaning is performed using the treated water, the consumption of the treated water is reduced, and the efficiency of the treated water production is improved.
Since the frequency of washing the fixed layer A can be significantly reduced, the amount of microorganisms held in the fixed layer A can be maintained at a high concentration for a long time, so that an efficient biological reaction can be promoted in the fixed layer A. There is no need to remove coarse foreign substances in raw water in advance. Since the physical properties of the filter medium are selected so that a high concentration of microorganisms can be retained inside the filter medium, a high-speed biological reaction can be ensured. (In the sewage treatment, a filtration speed of LV 120 m / day, which is five times that of the conventional BAF, can be obtained.) Due to the above effects, a. Reduction of installation area b. Reduction of construction costs c. Reduction of treatment consumption as washing water d. The four major effects of simplifying the process can be obtained, and all the disadvantages of the conventional BAF can be solved.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention.

FIG. 2 is a diagram for explaining an example of an elastic porous granular material used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing tank 2 Fixed layer A 3 Support floor 4 Space part 5 Fixed layer B 6 Support member 7 Oxygen-containing gas 8 Supply part 9 Water supply part for filter bed washing 10 Gas supply part for filter bed washing 11 Water supply part for filter bed washing 12 Gas supply for filter bed cleaning 13 Inflow 14 Washing drainage outflow 15 Outflow pipe 16 Upper interface 17 Treatment water tank 18 Porous material 19 Elastic porous granular material 20 Void 21 Valve 22 Valve 23 Valve 24 Discharge pipe

Claims (2)

(57) [Claims] 1. A fixing layer A made by filling a elastic porous granules arranged in the tank, via the space portion to the upper portion of the fixed layer A, made by filling a elastic porous granules fixed Providing layer B,
The organic wastewater fed from the upper portion of the fixed layer B, and the supply portion of the lower and the cleaning water and the oxygen-containing gas into the bottom of the fixed layer B of the fixed layer A is taken out of the treated water from the bottom of the fixed layer A The frequency of washing the fixed layer A is less than the frequency of washing the fixed layer B.
A biological filtration device for organic wastewater, wherein the biological filtration device is disposed so as to be eliminated . 2. The biological filtration device for organic wastewater according to claim 1, wherein the cleaning water supplied to a lower portion of the fixed layer B is the organic wastewater.