JPS5931399B2 - Wastewater treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wastewater treatment device, and particularly to a wastewater treatment device that can be used as a gray water generation device.

In recent years, large buildings being constructed in large cities are beginning to introduce gray water systems based on social demands such as energy conservation.

These gray water systems treat gray water and use it for flush toilets, car washes, water spraying, air conditioning equipment, etc., but especially when installed in buildings etc., they are small and have high processing performance. , and a wastewater treatment boat that is easy to maintain and manage.

As a wastewater treatment device that meets these demands, an aeration filtration type device that integrates standard activated sludge treatment and filtration functions has been proposed (Japanese Patent Application Laid-open No. 76848/1983), but this device It was difficult to say that it fully met the requirements of "low volume" and "resistance to fluctuations in inflow load."

The purpose of this invention is to eliminate the drawbacks of the conventional devices and provide a wastewater treatment device that is small, has high treatment performance, is easy to maintain, and generates little sludge and is resistant to fluctuations in inflow load. .

This invention includes a treatment tank, an aeration section provided in the upper part of the treatment tank, a filler layer and an aeration pipe provided in the aeration section, a raw water pipe for introducing raw water into the aeration section, and the treatment tank. A filtration section provided at the bottom of the tank, an upper filtration layer and a lower filtration layer provided in this filtration section, a treated water pipe that collects treated water from this lower filtration layer, and between the upper filtration layer and the lower filtration layer. This wastewater treatment apparatus is characterized in that it includes an air washing pipe provided therein and a backwash water pipe connected to introduce pressurized water in which air is dissolved under pressure into the bottom of the treatment tank.

The present invention will be explained below with reference to embodiments of the drawings.

FIG. 1 is a vertical sectional view of the embodiment, and the treatment tank 1 consists of a tank with a rectangular horizontal cross section extending in the front-rear direction toward the drawing, and is provided with an aeration section 2 at the top and a filtration section 3 at the bottom. .

A filler layer 4 that easily forms a microbial film having a purifying function similar to that of activated sludge microorganisms is provided on both sides of the aeration section 20, and an aeration chamber 6 is formed next to the filler layer 4 by a rectifier plate 5 in the center. The aeration chamber 6 is divided into two sections, and an aeration pipe I is provided at the lower part of the aeration chamber 6.

A raw water pipe 8 and an excess sludge removal pipe 9 are opened at the upper part of the aeration section 2, and a level controller 10 is also provided.

The filler layer 4 is constructed by filling corrugated plates, pipes, etc. in a vertically arranged manner so that liquid can flow vertically.

In the filtration section 3, an upper filtration layer 11 made of a filter medium with a low specific gravity such as anthracite and a lower filtration layer 12 made of a filter medium with a high specific gravity such as sand are stacked in two layers, upper and lower, on a support bed 13 made of gravel or the like. A treated water pipe 14 is provided below the lower filtration layer 12, and an air cleaning pipe 15 is provided between the upper filtration layer 11 and the lower filtration layer 12.

The treated water pipe 14 is provided with a water collection strainer 16, and the steam or air washing pipe 15 is provided with an aeration nozzle 1'7.

The treated water pipe 14 is connected to a treated water tank (not shown) via a solenoid valve 18 and a flow meter 19, and is connected to a backwash water pipe 2 from the treated water tank.
0 is connected to the treated water pipe 14 via a backwash pump 21, a pressurized tank 21a1, a flow meter 22, and a reverse valve 23.

A compressor 21b is connected to the pressurized tank 21a to dissolve air under pressure to produce pressurized water.

24 is a proa, which is connected to the aeration pipe 7 via a solenoid valve 25 and a flow meter 26, and also to the air cleaning pipe 15 via a solenoid valve 27 and a flow meter 28.

In the wastewater treatment device configured as described above, raw water is supplied from the raw water pipe 8, the solenoid valve 25 is opened to aerate from the aeration pipe I, and the solenoid valve 18 is opened to collect treated water from the treated water pipe 14. Processing is performed by

In the aeration section 2, due to the aeration from the aeration pipe 1, bubbles move up through the aeration chamber 6 together with the liquid in the tank, and supply oxygen to the liquid in the tank.

The rising tank liquid and the raw water supplied from the raw water pipe 8 mix and flow down the filler layer 4 to come into contact with the microbial film on the filler (repeatedly, and the BOD components in the waste water are decomposed and removed).

Even if there is no microbial film in the filler layer 4 at the initial stage of operation, as the operation continues, microorganisms in the wastewater and microorganisms mixed in from the air adhere and multiply, forming a microbial film.

Since the solid content in the wastewater is captured by the microbial film on the filler layer 4, the amount of sludge suspended in the liquid is reduced.

The liquid that has been aerated in the aeration section 2 is filtered one by one in the filtration section 3 and collected in the treated water pipe 14 .

In this case, large solids suspended in the liquid are removed by an upper filtration layer 11 made of a large-particle filter medium, and small solids passing through this are removed by a lower filtration layer 12 which also contains a small-particle filter medium.
At the same time, COD components are also removed by microorganisms attached to the surface or between the filter media.

The treated water that has undergone the aeration, aeration and filtration treatment in this manner is sent from the treated water pipe 14 to the treated water tank.

If the filtration section becomes clogged due to continued processing, the filtration resistance increases and the liquid level in the processing tank 1 rises, which is detected by the level controller 10 and a filter medium cleaning process begins.

The cleaning process includes an air cleaning process and a backwashing process.
The air cleaning process restores the filtration ability to some extent, so
It is preferable to use a method in which only air cleaning is normally performed, and sometimes a backwashing process is also used.

: In the air cleaning process, the inflow of raw water is stopped and the solenoid valve 27
This is done by opening the air bubbles, introducing air bubbles from the air washing pipe 15, and stirring and loosening the upper filtration layer 11.

In this case, aeration from the aeration pipe 7 may or may not be performed.

As the liquid level rises due to the introduction of air bubbles, the peeled sludge is discharged from the excess sludge removal pipe 9.

In the backwashing process, the backwash pump 21 is started, the treated water is introduced into the pressurized tank 21a, and air is sent from the compressor 21b to dissolve it under pressure. This is carried out by introducing the water into the filtration section 3 via the water pipe 14.

The backwash water entering from the treated water pipe 14 flows upward to the lower filtration layer 1.
2 and the upper filtration layer 11 are expanded to separate the captured sludge and discharged from the excess sludge removal pipe 9.

During this time, it is not necessary to carry out aeration from the aeration pipe 1, but it is not necessary to carry out air supply from the air washing pipe 15 or not.

Even if air is not supplied from the air cleaning pipe 15 during backwashing, it is desirable to supply air and perform air cleaning prior to backwashing.

When pressurized water with dissolved air under pressure is used as backwash water,
When the backwash water enters the filtration section 3, the generated microbubbles adhere to the separated sludge, float the sludge, and drain the excess sludge discharge pipe S.
Since the sludge is discharged from the filler layer, heavy sludge can be floated and discharged with a small amount of backwash water, and therefore the biofilm formed on the filler layer 4 will not be peeled off.

After completing the washing step in this way, raw water is introduced again and the above-mentioned process is repeated.

FIG. 2 is a system diagram when the present invention is implemented in a gray water generation system in a building. The same reference numerals as in FIG. 1 indicate the same parts, and the pressurized tank 21a and compressor 21b are omitted from the illustration. ing.

30 is a raw water tank, 31 is a treated water tank, 32 is a disinfection tank, 33 is a gray water elevated water tank, and 434 is a sludge storage tank.

In the gray water desalination system configured as described above, the wastewater entering the raw water tank 30 from the drain pipe 35 is transferred to the sludge storage tank 34.
It is pre-aerated by the proa 31 together with the supernatant water returned through the return pipe 36, and a part of it is introduced into the treatment tank 1 from the raw water pipe 8 as raw water to be treated.

The treated water in the treatment tank 1 enters the treated water tank 31 from the treated water pipe 14 and is stored therein, is sent to the disinfection tank 32 by the pump 38 to be disinfected, and is further transferred to the gray water elevated water tank 3 by the pump 39.
Water is sent to 3rd.

The water in the elevated gray water tank 33 is distributed from the water distribution pipe 40 to flush toilets and the like as gray water.

The treated water in the treated water tank 31 is sent to the treatment tank 1 from the backwash water pipe 20 during backwashing.

Further, the sludge discharged from the excess sludge removal pipe 9 of the treatment tank 1 to the sludge storage tank 34 is aerated and stored by a blower 41, and after separating supernatant water, is drained from the sludge drainage pipe 42.

Next, we will show an example of the operation of a treatment device installed in a gray water production system in a building.Water flow is 1 d/day, residence time in the tank is approximately 5 hours, and gray water is treated for 1 minute every 2 hours of air washing. However, after about 3 months, the pressure loss in the treatment tank 1 increased, making treatment difficult.

Therefore, pressurized tank 21. Approximately 4kg/crNG in L
Pressurized water with dissolved air under pressure is introduced into the bottom of the tank once a day.
After backwashing for 50 seconds, the pressure drop returned to the initial level, and the pressure drop did not increase thereafter (the process could be carried out smoothly).

Table 1 shows the processing results in this case. In addition, when backwashing with pressurized water was not performed or when it was performed, there was no change in the quality of the treated water.

From the above results, it can be seen that according to the wastewater treatment apparatus of the present invention, high quality treated water can be obtained and can be used as gray water.

In the steam filtration type treatment device of the present invention, a filler layer is provided in the aeration section, so a microbial film is formed on the filler,
This microbial film enables catalytic oxidation of wastewater,
It has good processing efficiency, is resistant to fluctuations in inflow load, and can perform stable processing.

In addition, since it is only necessary to aerate the part of the aeration chamber, the amount of air supplied is small, and the processing cost can also be reduced.

Since the microbial membrane itself multiplies and self-extinguishes at the same time, less sludge is generated, and therefore less surplus sludge is generated to be treated.

Since the liquid treated in the aeration section is directly filtered in the filtration section, high quality treated water can be obtained and stability against fluctuating loads is also increased.

In this case, most of the suspended matter in the aeration section is captured by the filler layer, so the load on the filtration section is small, so there is no need to provide a settling tank, etc., and the number of times the filtration section is washed can be reduced. .

In the above embodiments, corrugated plates and pipes were used as the filler, but other fillers may be used as long as the microbial film can adhere to them, and their shape, structure, installation location, etc. Not limited.

Further, the filter material is not limited to anthracite or sand, but other materials can be used.

Furthermore, the wastewater treatment apparatus of the present invention is not limited to use in gray water production, but can also be applied to simple wastewater treatment and other uses.

As described above, this invention integrates biological catalytic oxidation function and filtration function, significantly reduces the amount of sludge generated compared to conventional equipment, is resistant to fluctuations in inflow load, is compact, and maintains high treatment performance. This has the effect of being easy to manage.

Therefore, the treated water can be used as gray water without degrading the quality of the gray water (running costs can be lower than with conventional equipment, and the sludge storage tank can also be made smaller).

Furthermore, if pressurized water is used to backwash the filter tank, heavy sludge can be effectively removed.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing an embodiment, and FIG. 2 is a system diagram showing a case where the invention is implemented in a gray water production system in a building. In each figure, the same symbols indicate the same parts, 1 is the processing tank, 2 &
``4 air sections, 3 is a filtration section, 4 is a filler layer, 5 is a rectifying plate, 6
is an aeration chamber, 1 is an aeration pipe, 8 is a raw water pipe, 11 is an upper filtration layer, 12 is a lower filtration layer, 13 is a support bed, 14 is a treated water pipe,
15 is an air cleaning pipe.

Claims (1)

[Claims] 1. A treatment tank, an aeration section provided at the top of the treatment tank, a filler layer and an aeration pipe provided in the aeration section, and a raw water pipe for introducing raw water into the aeration section. , a filtration section provided at the lower part of the treatment tank, an upper filtration layer and a lower filtration layer provided in this filtration section, a treated water pipe that collects treated water from the lower filtration layer, an upper filtration layer, and A wastewater treatment device comprising an air washing pipe provided between lower filtration tanks and a backwash water pipe connected to introduce pressurized water in which air is dissolved under pressure into the bottom of the processing tank. 2. The wastewater treatment device according to claim 1, characterized in that it includes a rectifier plate that partitions an aeration chamber next to the filler layer, and the aeration pipe is provided at a lower part of the aeration chamber. 3. The wastewater treatment device according to claim 1 or 2, wherein the upper filtration layer is made of anthracite and the lower filtration layer is made of sand.