JPS6331280B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for treating organic wastewater using microorganisms attached to granular material.

[Conventional technology]

Conventional soaked bed equipment has a tank filled with granular materials such as sand or anthracite in a tank with an air lift pipe, and air lift aeration supplies oxygen to the packed bed and circulates the liquid. It is widely used to treat organic wastewater.

That is, as shown in FIG. 1, a support bed 26 formed in a tank 28 is filled with granular material to form an immersed packed bed 24, and while raw water 21 flows downward, air 25 is Air lift tube 2 supplied
The treated water is subjected to aerobic biological treatment by the action of oxygen dissolved in the tank 3 and microorganisms in the immersed packed bed 24, and the treated water is discharged outside the system from the treated water outlet 22 located at the upper part of the tank 28. A backwash water pipe 27 is provided at the bottom of the tank.

[Problem that the invention seeks to solve]

However, in this conventional device, since the liquid is circulated in a downward flow in the immersed packed bed 24 on the support bed 26, clogging due to microbial slime that occurs when SS and BOD in the raw water 21 is removed is avoided. Therefore, it is necessary to periodically stop the inflow of raw water 21 and backwash the immersed packed bed 24 with backwash water from the backwash water pipe 27, which is not suitable for raw water 21 with high SS or high BOD. Moreover, not only is the scope of application narrow, but maintenance is troublesome as backwashing is required, and the aeration power efficiency is low because oxygen is supplied by air lift. This is a problem because a countercurrent occurs and the rising speed of the air bubbles is accelerated by this upward flow, shortening the residence time of the air bubbles in the water, and a support plate 26 such as a perforated plate is required to support the submerged packed bed 24. There are also many troubles such as clogging of the support bed 26, and conventionally, small-sized granular materials cannot be used because the clogging problem occurs within a short period of time. As a result, high-quality treated water could not be stably obtained.

An object of the present invention is to provide an effective biological treatment device that can appropriately solve all of these conventional serious drawbacks.

[Means for solving problems]

The present invention forms a packed bed of granular material with a specific gravity of 1.0 or more under the water surface in a tank that has a raw water inlet and an oxygen-containing bubble feeder in the lower part and a treated water outlet in the upper part,
A material transfer pipe whose lower end is open is provided vertically in the lower part of the packed bed, and the upper end of this material transfer pipe is opened above the packed bed interface, and around it is a partition wall whose upper end protrudes above the water surface. A reflux part of the granular material is separated from a treated water outflow part, and a washing wastewater outflow pipe is provided in the reflux part for discharging washing wastewater separated from the granular material, and air is provided at the bottom of the material transfer pipe. comprising a supply pipe, the granular material is intermittently or continuously extracted from the lower part of the packed bed using supplied air bubbles, and is sucked into the material transfer pipe;
The biological treatment apparatus for organic wastewater is characterized in that the particulate material is circulated to the interface of the packed bed through a reflux part while being transferred to the upper part of the packed bed and while cleaning the particulate material.

〔Example〕

An embodiment of the present invention will be described with reference to FIG.
A conical (or pyramidal) bottom 13 having a diameter of 3' is provided, and a raw water inlet 1 is provided at the center of the lower end of the treatment tank 3 . In addition, the bottom part 13 and the processing tank 3
In the space 17 formed by the outer wall 3' of the filling tank 4, an aeration pipe 9 is arranged so as to diffuse air evenly over the entire horizontal cross section of the filling tank 4.

Furthermore, a draft tube 5 serving as a transfer pipe for granular material is provided vertically in the center of the treatment tank 3, and around the lower part of the draft tube 5, a packed bed 4 of granular material having a specific gravity of 1.0 or more, such as sand or anthracite, is provided. A space 10 is left above the filled layer interface 7. The upper part of the draft tube 5 is opened above the filled layer interface 7,
The lower part of the draft tube 5 is opened into the packed bed 4, and an air supply pipe 11 for generating an air lift is connected inside the draft tube 5.

Furthermore, a valve 12 is provided at the opening at the upper end of the draft tube 5 to prevent the raw water 1' from passing through the draft tube 5, so that the valve 12 can be opened and closed, and the opening 6 at the upper end can be opened and closed. There is.

The treatment tank 3 is equipped with a treated water outflow part 2 and an air supply pipe 8 connected to an aeration pipe 9, and a particulate material return part 14 is provided in the upper part of the draft tube 5. It is provided with an outflow pipe 15 and a partition wall 16 for preventing washing wastewater after washing the granular material from flowing out to the treated water outflow section 2.

That is, a draft tube 5 whose lower end is open is vertically provided in the lower part of the packed bed 4, and the upper end of the draft tube 5 is opened above the packed bed interface 7, and around it, the upper end is above the water surface. The reflux part 14 of the granular material is separated from the treated water outflow part 2 by a partition wall 16 that protrudes from the outside, and a washing waste water outflow pipe 15 is provided in the reflux part 14 to allow the washing waste water separated from the granular material to flow out. and an air supply pipe 11 is provided at the lower part of the draft tube 5, and the granular material is intermittently or continuously extracted from the lower part of the packed bed 4 using the supplied air bubbles and sucked into the draft tube 5, The particulate material is transported to the upper part of the packed bed 4 and circulated to the packed bed interface 7 via the reflux part 14 while cleaning the particulate material.

Therefore, when the raw water 1' is supplied with the valve 12 in the draft tube 5 closed and the water is passed through the filling tank 4 in an upward flow, and the air 8' is fed from the aeration pipe 9, the raw water 1' The BOD components inside the air diffuser 9
Aerobic biological treatment is performed by oxygen supplied from air bubbles from the filling tank 4 and microorganisms attached to the granular material in the filling tank 4.

As this biological treatment operation continues, the packed bed 4
Microbial SS generated as SS and BOD in the raw water 1' are removed accumulates within the tank, but since the raw water 1' is passed in an upward flow, the hetudross increases beyond a certain value. When this happens, a part of the packed bed 4 expands slightly, and the SS that has been trapped until then escapes, thereby suppressing an increase in hedose loss.

However, if only water is used during such normal biological treatment, clogging remains in the packed bed 4, and eventually an extreme drift of the raw water 1' occurs in the packed bed 4.
Since the desired biological treatment becomes impossible, the valve 12 is opened intermittently to feed air 11' into the draft tube 5 from the air supply pipe 11. Due to this operation, an air lift effect occurs in the draft tube 5, so that the granular material at the bottom of the packed bed 4 is sucked from the lower end of the draft tube 5, which serves as a material transfer pipe, and the inside of the draft tube 5 is violently disturbed together with air bubbles. The material is washed while being transferred with the flow, overflows from the opening 6 at the upper end and flows into the reflux section 14, and then falls onto the packed bed interface 7, and the refluxed and contaminated material can be extracted from above and cleaned at all times. The material can be maintained in optimal condition. Thus, after a certain period of time, all of the granular material in the packed bed 4 is transferred to the draft tube 5.
had accumulated in the packed layer 4 until then.
The SS and extra microorganisms are effectively removed, and the SS and extra microorganisms are removed together with the washing wastewater from the washing wastewater outflow pipe 1.
5 and is discharged from the system. In this case, the partition wall 16 prevents the cleaning wastewater from flowing into the treated water outflow portion 2 .

Although the granular material cleaning operation described above was performed intermittently, it is also possible to perform this continuously. In this case, the air diffuser pipe 9 and the air supply pipe 11
Air 8' and air 11' are fed in parallel from each other, and raw water 1' is supplied from the wafer, treated water 2' is fed from the treated water outlet 2, and wash water is fed from the wash water outlet pipe 15 in parallel. (A part of the raw water 1' is discharged to the draft tube 5,
The remainder rises in the packed bed 4). In addition, in order to prevent the raw water 1' sucked into the draft tube 5 from short-passing to the treated water outflow section 2, the discharge amount of the treated water 2' must be set to be greater than the discharge amount of the washing wastewater. is more preferable. As described above, according to the present invention, granular material can be washed simultaneously during normal biological treatment.

In the present invention, instead of providing the valve 12 as in the example shown in FIG. 2, the upper end of the draft tube 5 may be opened and the upper end may be raised to a higher position than the water surface. It is possible to prevent the raw water 1' from flowing out of the system through the draft tube 5 from the cleaning wastewater outflow pipe 15 by a shot pass. In addition, as shown in Figure 3, if the raw water inlet and air diffuser are arranged in a distributed manner on the bottom of the treatment tank 3, the granular materials around the tank bottom (the shaded area in the figure) will remain stationary and will naturally have an angle of repose. is formed,
Some granular materials move along the angle of repose, so
It becomes possible to omit the conical or pyramidal porous bottom plate 13 of the previous example.

Note that instead of performing the cleaning operation for the particulate material in the packed bed 4 in the processing tank 3, the upper part and the lower part of the packed bed 4 are connected by a circulation path equipped with a pump such as a centrifugal pump, and the particulate material is The cleaning may be carried out while moving the granular material through the circulation path (if desired, pressurized air or the like may be blown into the circulation path to promote agitation of the granular material).

In the embodiment shown in FIG. 4, the bottom of the processing tank 3 is constituted by a conical bottom 13, and a plurality of aeration tubes 9 are disposed close to the bottom plate 13, and a plurality of radial (annular) aeration tubes 9 are arranged concentrically. It is also possible to apply a processing device having a structure arranged in

〔Effect of the invention〕

The present invention forms a packed bed of granular material with a specific gravity of 1.0 or more under the water surface in a tank that has a raw water inlet and an oxygen-containing bubble feeder in the lower part and a treated water outlet in the upper part,
A material transfer pipe whose lower end is open is provided vertically in the lower part of the packed bed, and the upper end of this material transfer pipe is opened above the packed bed interface, and around it is a partition wall whose upper end protrudes above the water surface. A reflux part of the granular material is separated from a treated water outflow part, and a washing wastewater outflow pipe is provided in the reflux part for discharging washing wastewater separated from the granular material, and air is provided at the bottom of the material transfer pipe. comprising a supply pipe, the granular material is intermittently or continuously extracted from the lower part of the packed bed using supplied air bubbles, and is sucked into the material transfer pipe;
By having a structure in which the particulate material is transferred to the upper part of the packed bed and circulated to the packed bed interface through the reflux part while being washed, there is no problem even when using particulate material with a small particle size and a large specific surface area. No clogging occurs. Therefore, maintenance is easy and processing efficiency is improved, and since oxygen-containing bubbles such as air are directly supplied into the immersed packed bed, the bubbles do not escape into the atmosphere in a short period of time during aeration using an air lift, unlike conventional methods. As a result, the residence time of the bubbles becomes longer, and the oxygen supply power efficiency is approximately three times that of the conventional method, resulting in a stable 3Kg・O ₂ /KWH. Since the supporting bed (see Figure 1) that supports the immersed packed bed is not required, there is no problem of clogging of the holes in the supporting bed, and the air supply to the draft tube requires no aeration. Since it is not a specific purpose, it can be done intermittently and for a short time, so the power consumption is much lower than the conventional method.Furthermore, the structure is simple as there is no need to limit the bottom of the treatment tank to a tapered shape. In addition to making production easier, biological treatment of raw water and cleaning of granular materials can be performed in parallel.
Moreover, since it can be carried out continuously, there is no need to interrupt the biological treatment for the cleaning operation, and the granular material can always be maintained in an optimal state, and high-quality treated water can be stably obtained.

[Brief explanation of the drawing]

FIG. 1 is a system explanatory diagram showing a conventional method, FIG. 2 is a system explanatory diagram of one embodiment of the present invention, and FIGS. 3 and 4 are system explanatory diagrams of a part of other embodiments. 1... Raw water inlet, 1'... Raw water, 2... Treated water outlet, 2'... Treated water, 3... Treatment tank, 3'...
...Outer wall, 4...Filled bed, 5...Draft tube, 6...Opening, 7...Filled bed interface, 8...Air supply pipe, 8'...Air, 9...Diffusion pipe, 10...
...Space part, 11...Air supply pipe, 11'...Air,
12...Valve, 13...Bottom plate, 13'...Air supply hole, 14...Recirculation section, 15...Washing drainage outflow pipe,
16... Partition wall, 17... Space section.

Claims (1)

[Scope of Claims] 1. Specific gravity under the water surface in a tank with a raw water inlet and an oxygen-containing bubble feeder in the lower part and a treated water outlet in the upper part.
A packed bed is formed with granular material of 1.0 or more, and a material transfer pipe whose lower end is open is vertically provided in the lower part of the packed bed, and the upper end of this material transfer pipe is opened above the interface of the packed bed. A washing wastewater outflow pipe is formed around the periphery to separate the reflux part of the granular material from the treated water outflow part by a partition wall whose upper end protrudes above the water surface, and further drains the washing wastewater separated from the granular material into the reflux part. and an air supply pipe at the bottom of the material transfer pipe, and the granular material is intermittently or continuously extracted from the lower part of the packed bed using the supplied air bubbles, sucked into the material transfer pipe, and then A biological treatment device for organic wastewater, characterized in that the granular material is circulated to the interface of the packed bed via a reflux section while being transported to the upper part of the bed and washed. 2. The packed layer is filled on a conical plate having air supply holes, and is arranged above an air diffuser in a space formed between the conical plate and the outer wall of the tank. A biological treatment device according to claim 1, which comprises: 3. The biological treatment apparatus according to claim 1, wherein the filling tank has a raw water inlet and an aeration port arranged in a distributed manner so that an angle of repose is formed in the movement of the shaped materials. 4. The biological treatment apparatus according to claim 1, wherein the packed bed is provided in a conical tank bottom, and an aeration pipe is installed close to the conical tank bottom.