JPH0717438Y2 - Organic wastewater treatment equipment - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a new device capable of extremely highly purifying organic sewage such as sewage, night soil, and various industrial wastewater, and in particular, the drawbacks of the activated sludge method The present invention relates to a device that can be largely eliminated.

[Conventional technology]

The biggest drawback of the activated sludge method is that the sedimentation property of the activated sludge in the final settling tank following the aeration tank is extremely unstable,
This is the point at which SS will carry over from the settling basin and deteriorate the quality of the discharged water. Therefore, the BOD of the effluent of the treatment plant is 15
〜20mg / l, SS is only about 50〜70mg / l, and pollution of rivers, lakes and marshes into which treated water of such quality inflows more and more, and The fact that water quality conservation cannot be achieved at all is an unmistakable reality.

In order to deal with such a problem, recently, an aerobic biological bed method has been studied in which the overflow water of the final sewage sedimentation tank is sanded or the SS is aerated while aerating from the bottom of the bed filled with anthracite. There is.

[Problems to be solved by the device]

However, the sand filtration and the aerobic biological bed method have the following serious drawbacks and are not widely used.

That is, if a large amount of SS carries over from the final settling tank, the floor will be clogged immediately and it will be impossible to continue operation.

Since the overwater must be used as the washing water during the washing for clearing the floor clogging, the overwater production efficiency is poor.

Even by sand filtration or biological bed method, it is completely impossible to stabilize the BOD of the superfluous water to 1 to 2 mg / l.
The BOD of overwater is only about 5 to 15 mg / l, which is completely unsatisfactory for the conservation of water quality in public water bodies.

Even in a normal situation where a large amount of SS does not carry over from the final settling tank, 30 to 70 mg / l of SS flows into the excess tank from the final settling tank, so frequent floor cleaning is required once or twice a day. It is possible to continue for a long time (for example, 3 to 4).
There is a long-felt need for a method that requires only one wash per day.

The present invention aims to completely solve the drawbacks of the prior art.

[Means for Solving the Problems]

The present invention is an aeration tank for biological treatment of organic wastewater,
A treatment tank having a floating material layer in the upper portion and a lower portion as a sedimentation portion, a slurry inflow portion from the aeration tank being provided in the sedimentation portion, and a primary treated water outflow portion in the upper portion of the tank; An apparatus for treating organic sewage, comprising an aerobic biological bed apparatus provided with a bed of granular material communicating with the primary treated water outflow section, and the primary treated water outflow section of the treatment tank. A storage tank is interposed in a communication passage between the aerobic biological bed apparatus and the aerobic biological bed apparatus, and a flow path for press-fitting the primary treated water of the storage tank into a lower floor of the aerobic biological bed apparatus is provided. It is a treatment device for organic wastewater.

[Action]

First, organic sewage such as sewage flows into the aeration tank configured as described above, and undergoes biological treatment. As the biological treatment, not only BOD removal but also a biological dephosphorization process or nitrification denitrification process may be incorporated. The activated sludge slurry that has undergone biological treatment and flows out from the aeration tank flows into the sedimentation section below the next treatment tank, and most of the activated sludge is separated by sedimentation.

Now, the fine SS that could not be completely settled in the settling part flows upward into the levitation material layer in the upper part and is excessively removed to become the primary treated water. In addition, since a biofilm has developed on the surface of the material of the floating material layer, SS is effectively removed by contact precipitation and excessive action, and at the same time soluble BOD is also removed by the aerobic or anaerobic biofilm. The quality of the primary treated water is significantly improved. For example, in the case of sewage treatment,
BOD and SS can be stably set to 5 to 15 gm / l.

With the above configuration, even if the settling property of activated sludge deteriorates, it is possible to always obtain the primary treated water with low BOD and SS.

Then, the primary treated water flowing out from the upper part of the flotation material layer of the treated layer flows into the upper part or the lower part of the aerobic biological bed apparatus from the primary treated water outflow part and goes down the floor under aerobic conditions. A small amount of SS, BOD, NH ₄ -N remaining in the primary treated water flowing through in countercurrent or upflow is highly removed in the bed,
SS, BOD, and NH ₄ -N are all highly purified final treated water of about 1 to 3 mg / l.

This final treated water can be discharged to public water bodies such as rivers, and unlike the discharge water of conventional sewage treatment, it is purer than the water quality of ordinary city river water, thus significantly promoting river purification. be able to. That is, the final treated water of the present invention can utilize the sewage treated water, which has been one of the largest pollution sources of urban rivers, as a purified water source of urban rivers, and contributes to the conservation of the living environment. However, it is extremely large.

Since the primary treated water that flows into the floor of this aerobic biological floor system has a small amount of SS, BOD, etc., the floor clogging is extremely slow even with downward circulating water, and the floor is treated for a long time. No need for cleaning and maintenance is easy.
Also, when water is passed through the floor in an upward flow, there is an important feature that the support floor below the floor does not become clogged because the SS is low.

Now, as the above treatment is continued, due to the increase in the amount of SS accumulated in the floating material layer and the proliferation of biofilm,
As the over resistance increases, the levitation material layer is washed.

Various methods are conceivable as the cleaning method, and any method may be adopted. For example, the following method can be recommended.

That is, while the activated sludge slurry is flowing in, the amount of air diffused from the air diffuser is rapidly increased to generate a violent disturbing water flow (gas-liquid mixed phase flow) in the floating material layer. Due to this violently disturbed water flow, the SS in the timber layer is washed out, and is discharged along with the cleaning drainage. This cleaning wastewater is introduced to the first settling tank in the previous stage of the aeration tank, and SS in the water is separated by sedimentation, or is introduced to the aeration tank and then reaches the treatment tank again to reach the treatment tank.
SS is settled and separated. As a result, for cleaning the floating material layer,
There is no need to use the primary treated water flowing out from the treatment tank or the final treated water flowing out from the aerobic biological bed apparatus, and rational cleaning can be performed.

Next, although the progress of clogging on the floor of the aerobic biological bed apparatus is extremely slow, the over resistance reaches a predetermined value (about 500 mmH ₂ O) as it continues for 6 to 7 days. Wash in any suitable way.

That is, as in claim 2 of the present invention, the storage tank is interposed in the communication passage between the primary treated water outlet of the treatment tank and the aerobic biological bed apparatus to temporarily store the primary treated water in the storage tank. In this way, a flow path for pressurizing the stored primary treated water into the lower part of the floor of the aerobic biological bed apparatus is provided. Therefore, when cleaning the floor of the aerobic biological bed apparatus, the primary treated water in the storage tank is pressed into the lower part of the bed to disturb the floor for cleaning. At this time, it is not necessary to stop the aeration for keeping the floor aerobic. In addition, the cleaning wastewater is introduced to the first settling tank in the previous stage of the aeration tank to separate SS in water, or is introduced to the aeration tank and reaches the treatment tank to separate SS in water.

As described above, in the present invention, it is not necessary to waste clear treated water for washing the floor of the aerobic biological floor apparatus, unlike the conventional apparatus, and the production efficiency of the treated water is high.

〔Example〕

An embodiment of the present invention will be described with reference to FIG. 1. Air from a blower 3 is diffused in an aeration tank 2 equipped with a raw water inflow pipe 1 for guiding raw water (sewage and other organic sewage). An air diffuser 4 is provided.

5 is a treatment tank, and in the upper part of the tank, there is a levitation material layer 6 filled with styrofoam, polypropylene foam, wood chips, pumice, sponge and any other levitation material that floats in water with a specific gravity of less than 1.0. It is provided, and its upper part is covered with a water-permeable supporting member 7 such as a net to prevent the levitation material layer 6 from flowing out. However, if the specific gravity of the levitation material is close to 1.0, the exposure rate on the water surface is small. The support member 7 is not always necessary. Further, an oxygen-containing gas such as air is diffused inside or under the levitation material layer 6 to supply oxygen to the aerobic biofilm developed on the surface of the levitation material layer 6, and at the time of cleaning the levitation material layer 6. In order to increase the volume and promote the cleaning effect,
An air diffuser 8 is provided for diffusing an oxygen-containing gas such as air.

A lower part of the inside of the treatment layer 5 is formed as a settling part 9, and a slurry inflow pipe 10 for guiding the slurry flowing out from the aeration tank 2 is opened in the settling part 9.

Further, an overflow launder 11 serving as a primary treated water outflow portion is provided above the treatment tank 5, and a primary treated water outflow pipe 12 is connected thereto.

13 is a sludge pipe connected to the bottom of the treatment tank 5, and 14 is a settling section 9.
The sludge return pipe for returning the settled sludge 15 of No. 1 to the aeration tank 2 is shown.

21 is an aerobic biological floor device, anthracite inside,
A floor 22 filled with a granular material having a specific gravity of 1.0 or more, such as sand or granular activated carbon, is provided, and an aeration pipe 23 for aeration is provided below the floor 22. In addition, aerobic biological floor equipment
A known type can be used for 21, but in order to aerobically maintain the entire inside of the tank, the one as in this embodiment is preferable.

Further, the primary treated water outflow pipe 12 at the upper part of the treatment tank 5 is opened to communicate with the upper portion inside the aerobic biological bed apparatus 21, and the primary treated water that has passed through the floor 22 in a downward flow is the final treated water. Turned floor 22
The final treated water outflow pipe 24 is connected to the lower part of the pipe. The opening position of the primary treated water outflow pipe 12 in the aerobic biological bed apparatus 21 and the opening position of the final treated water outflow pipe 24 are turned upside down from the illustrated example, and the primary treated water is directed upward on the floor 22. It is also possible to let it flow through and then flow out from the upper part.

Further, in the present invention, a storage tank 31 for temporarily storing the primary treated water flowing into the aerobic biological bed apparatus 21 is interposed in the middle of the primary treated water outflow pipe 12, and the storage tank 31 and the aerobic biological bed apparatus 21 are provided. It is desirable that the lower part of the floor 22 in the inside is communicated with a cleaning water pipe 33 equipped with a pump 32 to make it convenient for cleaning the floor 22.

Furthermore, at the time of cleaning the floating material tank 6 in the processing tank 5, the cleaning wastewater can be guided to the storage tank 31, and in that case, the cleaning wastewater in the storage tank 31 is first transferred to a settling tank (not shown) or Piping equipped with a pump 34 for leading to the aeration tank 2.
It is preferable to attach 35 to the storage tank 31.

[Effect of device]

The present invention further provides an aerobic biological filter apparatus comprising a floating filter material layer provided above the sedimentation tank after the aeration tank of the activated sludge method, and the effluent water from the floating filter material layer further comprising a packed bed of granular filter material. By performing the processing, the following effects 1 to 3 can be obtained.

The quality of the discharged water to the public water area can be remarkably high at 1 to 3 mg / l for each of SS, BOD and NH ₄ -N, so it can be used as a purified water source for urban rivers.

Supply water to the aerobic biological bed equipment installed at the final stage
SS can be stably lowered even when the settling property of activated sludge is deteriorated. As a result, the progress of clogging of the aerobic organism bed is significantly reduced, and maintenance is significantly facilitated. In addition, the nitrification reaction in the aerobic organism bed part also easily progresses.

Since it is not necessary to use superfluous water to wash the flotation material layer and aerobic biological bed, the production efficiency of superfluous water is high.

Even when the settling property of activated sludge is deteriorated, it is possible to stably obtain highly treated water.

Since it is not necessary to pay particular attention to the sedimentation property of the activated sludge, the operational management of the activated sludge treatment becomes very easy.

The cleaning cycle of the aerobic biological bed can be significantly reduced as compared with the conventional one, so that the biota in the bed is stabilized and the quality of the perhydrogenate 15 is stable.

BOD removal function of raw water, activated sludge treatment and subsequent 2
Since it is divided into 3 stages of biofilm treatment, it is remarkably stable against fluctuation of raw water BOD, and always has good discharge water quality (BOD,
SS, NH ₄ -N several mg / l or less) can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention. 1 ... Raw water inflow pipe, 2 ... Aeration tank, 3 ... Blower, 4,
8,23 ... Air diffuser, 5 ... Treatment tank, 6 ... Floating material tank, 7
...... Supporting member, 9 ・ ・ ・ Settling section, 10 ・ ・ ・ Slurry inflow pipe,
11 …… Overflow ronder, 12 …… Primary treated water outflow pipe, 13 ……
Sludge pipe, 14 …… Sludge return pipe, 15 …… Settled sludge, 21 …… Aerobic biological bed equipment, 22 …… Bed, 24 …… Final treated water outflow pipe, 31 …… Storage tank, 32,34… … Pump, 33 …… Cleaning water pipe, 35 …… Piping.

Claims (2)

[Scope of utility model registration request] 1. An aeration tank (2) for biologically treating organic sewage, which has a raw water inflow pipe (1), and then holds a floating filter material layer (6) made of a floating filter material in the upper part and holds it downward. The part is set as a settling part (9), the slurry inflow part (10) from the aeration layer (2) is provided in the settling part (9), and the primary treated water outflow part (11) is provided in the upper part of the tank. An aerobic system in which a treatment tank (5) is provided, the primary treated water outflow section (11) of the treated tank (5) is a primary treated water outflow pipe (12), and a filter bed (22) of granular filter media is provided. An apparatus for treating organic sewage, which is connected to a biological filter device (21). 2. The primary treated water outflow portion (1) of the treatment tank (5)
The storage tank (31) is interposed in the primary treated water outflow pipe (12) that communicates between 1) and the aerobic biological filter device (21).
The organic wastewater according to claim 1, further comprising a washing water pipe (33) for press-fitting the primary treated water of the storage tank (31) into the lower part of the filter bed (22) in the aerobic biological filter apparatus (21). Processing equipment.