JPS5938833B2 - Biological treatment equipment for high concentration wastewater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a biological treatment device for highly concentrated wastewater such as urban sewage or industrial wastewater using aerobic microorganisms.

Activated sludge method and sprinkling bed method have been commonly used as methods for treating urban sewage or industrial wastewater.

However, the activated sludge method requires a large site area;
There are drawbacks such as difficulty in applying it to high-concentration wastewater and the need to manage the amount of returned sludge in accordance with the wastewater concentration.

Next, in the case of the sprinkling bed method, since it is a vertical device, the installation area is smaller compared to the normal activated sludge method, and although it has the advantage of being easier to maintain and manage, it also has the following disadvantages: There is.

(a) Since the treated raw water enters from the top of the device, the odor of the raw water wafts around as it is exhausted from the top of the device.

(b) In order to effectively utilize the surface of the R5 bed packing, it is necessary to disperse the raw water extremely uniformly at the top of the equipment, but this is an extremely difficult problem in actual equipment, and even if completely uniform dispersion is not possible, Even if this is possible, fluctuations in the discharge amount are unavoidable because microorganisms will grow in the raw water outlet where the raw water and air come into contact while the device is operating.

(c) This only reduces the utilization efficiency of the filling material.”
, so-called saw bed flies occur in areas where water is difficult to flow.

(d) The decomposition rate of wastewater by microorganisms is not as fast as normal chemical reactions, so sufficient contact time with microorganisms is required, but the residence time of water flowing down the packing surface is maintained for a sufficiently long time. Therefore, it is necessary to return some of the treated water to the raw water side and repeat the treatment, which reduces the efficiency of the device.

(e) Returning a portion of the treated water to the supply side changes the overall flow of the liquid from an extrusion flow to a completely mixed flow (this means that if a high removal rate is required, a sprinkling flow is required). It is necessary to increase the number of floor equipment.

(f) Since the water falling down the P floor is accompanied by an air current when falling, air bubbles adhere to the sludge flocs in the sludge settling and separation tank at the bottom of the bed, resulting in extremely poor sludge settling.

The present invention aims to provide a biological treatment device for highly concentrated wastewater that eliminates the drawbacks of the conventional methods as described above, and is a device in which a fixed packed bed and a floating packed bed are provided with the floating packed bed at the bottom. The apparatus is characterized in that a conduit for supplying gas and a conduit for supplying raw water are provided at the bottom of the main body, and a treated water discharge conduit is provided at the top of the main body.

Here, the floating packed bed means that the dynamic sedimentation velocity in the stationary liquid is 60
Any filler having crn/S or less or a specific gravity relative to the liquid of 1.5 or less may be used.

Such a floating packed bed repeatedly moves or vibrates as appropriate due to the upward flow of gas and liquid, and is effective in preventing the formation of excessive microbial film and clogging of the gas and liquid channels.

The configuration of the present invention will be explained in detail below based on the drawings.

Reference numeral 1 denotes the main body of the processing apparatus in the second column, in which a fixed packed bed is formed above a support grid 4.

Any kind of filler may be used to fill this fixed packed bed.

3 is a floating packed bed, and 5 is a partition grid.

6 is a gas distributor, and a gas supply conduit 7 is installed in the center of the lower part of the distributor.
The open end of the door is facing out.

Therefore, gas, such as pure oxygen gas, supplied from the gas supply conduit 7 at an appropriate pressure is uniformly dispersed by the gas distributor, rises inside the processing apparatus main body 1, and is led out from the upper part.

In the drawings, an open structure is shown, but a covered structure is also possible, in which case the undissolved gas is circulated and used.

8 is a raw water supply conduit, and raw water is supplied from the supply conduit 8 to the lower part of the processing device main body 1 by a pump (not shown).
The post-treated water is discharged from a discharge conduit 9 that has been treated by a cleaning action to be described later.

10 is a sludge settling tank, and 11 is a sludge extraction pipe.

Next, the cleaning effect of the processing device according to the present invention will be explained.

The concentrated raw water supplied from the supply conduit 8 first passes through the floating packed bed 3.
Inside, it contacts the gas supplied from the gas supply conduit 7 and dispersed by the gas distributor 6, and is oxidized and purified.

Since the filler floats in this floating packed bed 3, it is easy for the liquid to mix (but there is no blockage due to slime). It is desirable that the BOD is 200 ppm or less.

) The liquid is introduced into the fixed packed bed 2.

In this fixed packed bed 2, large movements of liquid due to the filling material,
In other words, the short bath is blocked, so the liquid as a whole flows in a state very close to the extrusion flow (.

That is, in the entire system, concentrated raw water is treated in the lower floating packed bed 3, and the final high-level treatment is performed in the fixed packed bed 2.

The present invention has the above-described configuration, and there is no need for return sludge, and since the treated water exits from the upper part of the tower, there is no problem with odor.

In addition, excess sludge settles in the form of large flocs in the sedimentation chamber at the bottom of the tower.

Generally, when biologically treating concentrated wastewater, a large amount of slime is generated, which tends to cause clogging between the fillers.
In the present invention, a floating packed bed filled with a packing that moves or vibrates with the flow of gas and liquid is provided at the bottom of the device that comes into contact with raw water, so that excess microbial film attached to the surface of the packing is can be automatically removed.

Example 2 A support grid is provided at a distance of 2000T1.111 from the top of a tower with a diameter of 1000wφ and a height of 4000van, and a partition grid is provided at a location of 3000van from the top of the tower, with a diameter of 10.1mm between the support grid and the partition grid. φ polystyrene sphere (sedimentation velocity 11 am/S, specific gravity 1.04)
was filled to form a floating packed bed, and the upper part of the support grid was filled with gravel with an average diameter of 10wφ to form a fixed packed bed.

A liquid having the composition shown in the table below is supplied at a rate of 30007/hr at 25°C, and the air is 8000A! It was supplied at a ratio of /=.

When the decomposition rate of the substrate (glucose) was measured, the removal rate was 41% in the floating packed bed and 74% in the fixed packed bed.
There was no problem of clogging in the packed bed due to excess slime.

Example (2) Water was treated under the same conditions as in Example (2) by filling polyethylene spheres with a specific gravity of 0.95 and a diameter of LoHφ in place of the polystyrene spheres in the floating packed bed.

The removal rate with the floating packed bed was 39%, and the removal rate with the fixed packed bed was 75%.

No problems with clogging due to excess slime occurred.

Comparative Example The same conditions as in Example (2) were used, and the packed bed was filled with gravel with an average particle size of 10 to φ, and all fixed beds were used.

Approximately one week after the microbial film was formed, the lower part of the packed bed became clogged with slime, making stable operation impossible.

[Brief explanation of drawings]

The drawings are schematic diagrams illustrating one embodiment of the invention. 2... Fixed packed bed, 3... Floating packed bed, 7... Gas supply conduit, 8... Raw water supply conduit, 9... Treated water discharge conduit.

Claims (1)

[Claims] 1. With the floating packed bed on the bottom, a conduit for supplying gas and a conduit for supplying raw water are provided at the bottom of the device body, which has a fixed packed bed and a floating packed bed, and a treated water discharge conduit is installed at the top of the device body. A biological treatment device for highly concentrated wastewater, which is characterized by the following: