JPH0372997A - Water treatment device - Google Patents

Abstract

PURPOSE:To stabilize the formation of a biological membrane and prevent the outflow of excess sludge by controlling the height of interface of a gas-liquid separation cylinder with a built-in air-lift tube and sludge in a precipitating section defined with a jacket within the given range. CONSTITUTION:An air diffusion tube 25 of pressurized gas below an air-lift tube 24 concentric to a reaction tank main body section 22' and a flow inlet of a waste water pipe 35 on the upper section of a gas-liquid separation cylinder 31 upside are continuously connected with, and a carrier 47 on which an aerobic biological membrane 50 is formed and a suspension flow 48 containing foams 49 is circulatedly flowed through the air-lift tube 24. Also, the treated water is received by a precipitated section 33 continuously communicating with the gas-liquid separation cylinder 31 to separate supernatant 51 and sludge 52, and interface detecting and controlling means 40 and 46 for precipitated sludge 52 are provided. The concentration of suspension liquid 48 is made higher by controlling the height of sludge interface of the precipitated section 44 within the given range to accelerate the formation of a biological membrane 50 on the surface of the carrier 47. The concentration of suspension liquid 48 is made lower by controlling the sludge interface in the post-processing to lower the ventilation volume, enabling to avoid the overflowing of excessive sludge 52 lower flown from the precipitated section 33.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention generally relates to water treatment equipment, and particularly to water treatment equipment that biologically treats sewage, industrial wastewater, etc. The present invention relates to a water treatment device equipped with a reaction tank that uses a membrane to remove organic matter from wastewater.

(Prior Art) FIG. 7 is a partial schematic vertical sectional view showing the configuration of a water treatment device according to the prior art. The outline of the water treatment device illustrated in FIG. 7 is as follows. That is, in FIG. 7, sewage, industrial wastewater, etc. (hereinafter simply referred to as "wastewater") 1 is guided through a wastewater pipe 2 and flows into a reaction tank 3 from above.
sent inside. On the other hand, air pressurized by an air source (that is, a device that pressurizes air, such as a compressor or a blower) 4 is sent into the reaction tank 3 from below the reaction tank 3 through an air introduction pipe 5 . When air bubbles 6 are generated in the reaction tank 3 by introducing this pressurized air into the reaction tank 3, the air bubbles 6 cause the suspension remaining in the reaction tank 3 (i.e., the As the wastewater 1 flows into the reaction tank 3, floating sludge (hereinafter referred to as E, hereinafter referred to as E) 8 remaining in the reaction tank 3 and carriers (i.e. , sand carried in advance to the west of reaction tank 3,
Refers to substances with specific gravity greater than 1, such as ceramics and activated carbon. These substances are called carriers.

Activated sludge called sludge from a sewage treatment plant (c) is usually adhered to this carrier, thereby forming an aerobic biofilm 9 (described later) 7). As described above, the suspension 111M8 and the carrier 7 are connected to the reaction tank 3.
An aerobic biofilm (i.e., refers to various organisms involved in water treatment) formed on the surface of the carrier 7 by flowing through the wastewater 1. 9 removes the organic matter contained in the wastewater 1. It purifies the wastewater by biologically oxidizing the H substance in the water, making it inorganic, and it cannot live without air. In this way, the waste water 1 is removed by the aerobic biofilm 9 and becomes treated water 11, which is then discharged into a river or the like through the drain pipe 10.

When surplus sludge 12 is generated as the wastewater treatment process described above is carried out, this surplus sludge 12 is transferred to the reaction tank 3.
It precipitates and accumulates in the precipitation part 13 formed above.

Excess sludge 12 that has settled and accumulated in the settling section 13 is discharged to the outside through the discharge pipe 15 by opening an on-off valve 14 that opens and closes the discharge pipe 15 communicating with the settling section 3.

(Problems to be Solved by the Invention) By the way, in the conventional water treatment device having the above-mentioned configuration, when starting up the water treatment device (i.e., at the time of startup)
Since the CFI degree of the suspension 8 in the reaction tank 3 is usually low, it takes about 1 to 3 months for the aerobic biofilm 9 to form on the carrier 7. Therefore, there is a problem that the maintenance and management of the water treatment equipment at the time of startup becomes a national problem. In addition, when the water treatment equipment is operated continuously, the concentration of the suspension 8 inside the reaction tank 3 increases, so as the concentration of the suspension 71 increases, surplus Sludge] 2 interface (boundary W surface between treated water 11 and surplus sludge 12) also rises, and a portion of surplus sludge 12 finally flows out together with treated water 11 through the drain pipe 10 into the river. , there was a risk that problems similar to those caused by unpurified wastewater flowing directly into rivers, etc., would occur.

Therefore, the present invention has been made in order to eliminate the above-mentioned problems and inconveniences. In addition to promoting the formation of aerobic biofilm on the surface of the imported carrier, during continuous operation of the water treatment equipment,
Highly reliable maintenance and management that enables stable water treatment by suppressing and preventing the sludge that settles and accumulates in the sedimentation section formed in the reaction tank from flowing out into rivers etc. along with the treated water. The aim is to provide easy water treatment equipment.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the water treatment device according to the present invention includes:
A carrier on which a biofilm is formed and wastewater flowing in from the outside are accommodated, and the wastewater and the carrier are ring-closed and flowed by pressurized gas supplied from the outside, and the wastewater is treated by the biofilm formed on the carrier. a sedimentation mechanism that communicates with the wastewater treatment mechanism and receives the treated water treated by the wastewater treatment mechanism and separates the treated water into a supernatant liquid and 1riE; an interface detection means for detecting the interface of the sludge separated by the sludge and outputting a predetermined detection signal; and a biofilm formation step in which a biofilm is formed on the carrier in response to the detection signal from the interface detection means. teeth,
On the other hand, in the subsequent process following the biofilm formation step, the height of the sludge interface in the sedimentation mechanism is set within a height closed range in which sludge does not flow out from the sedimentation mechanism. A control means is provided for controlling the height of the sludge interface in each of the steps so that the height of the sludge interface in the settling mechanism is lower than that of the sludge interface.

(Function) In the above configuration, in the biofilm formation step in which a biofilm is formed on the carrier, the height of the lG mud in the sedimentation mechanism is within the height range from which the lG mud does not flow out from the sedimentation mechanism. As such, by controlling the stiffness of the sludge interface within the settling mechanism, the concentration of suspended EJi (1) within the wastewater treatment machine (1) increases, which promotes the formation of biofilm within the carrier surface. On the other hand, post-processes following the biofilm formation step (i.e.,
By controlling the height of the sludge interface in the settling mechanism so that the height of the sludge interface in the settling mechanism is lower than that in the biofilm forming step, The concentration of the suspension in the wastewater treatment mechanism decreases, and as the concentration of the suspension decreases, the viscosity of the suspension decreases, which increases the aeration energy (i.e., pumping pressurized air into the wastewater treatment mechanism). (same as the aeration flow rate) has been reduced, making it possible to prevent excess sludge from flowing out from the settling mechanism in the post-process.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic explanatory diagram showing the overall configuration of a water treatment device according to an embodiment of the present invention.

In FIG. 1, the I\Using of the reaction tank 20 is formed to have a generally cylindrical shape as a whole, and a reaction tank main body portion 22' whose lower part is formed to have a roughly conical shape.
The reaction tank main body 22' is set above the reaction tank main body 22' to have a diameter considerably larger than that of the reaction tank main body 22' and to form a concentric shape with the reaction tank main body 22'.
' A sloped part 21 that continues to the upper end of ' and a slope part 21 that continues to the upper end of '
The jacket 23 includes a large-diameter cylindrical portion 22 and a jacket 23 . The inside of the jacket 23 includes a cylindrical part 28 having approximately the same diameter as the reaction tank main body part 22', a funnel part 29 continuing from this cylindrical part 28, and a small diameter cylindrical part 30 continuing from these two funnel parts. A gas fatigue separation cylinder 31 is provided so as to be concentric with the reaction tank main body 22'. At the lower part of the gas-liquid separation cylinder 3, there is provided communication between an inner space defined by the gas-liquid separation cylinder 31 and an outer space defined by the gas-liquid separation cylinder 31 and the jacket 23. A communication port 32 is provided for this purpose. A sedimentation section 33 is located below the outer space defined by the gas-liquid separation cylinder 31 and the jacket 23 . In the inner space defined by the reaction tank main body 22' and the gas-liquid separation cylinder 31, there is an air lift pipe 24 having a cylindrical shape with an open upper and lower part. ' and the gas-liquid separation cylinder 31.

Below the air lift pipe 24, that is, the reaction tank main body 2
A diffuser pipe 25 is provided below 2', and this diffuser pipe 25 is connected to an air source 27 through an air introduction pipe 26. The upper part of the air lift pipe 24, that is, the upper part of the gas-liquid separation cylinder 3] is open, and the downstream end of the waste water pipe 35 is opened in this opening.

In the inner space defined by the reaction tank main body 22' in which the air lift pipe 24 is disposed and the gas-liquid separation cylinder 31, a carrier 47 such as sand, anthracite, activated carbon, ceramic, etc. It is filled in advance by about 1 to 10% (V/V). The specific gravity of the tI-L body 47 is greater than the specific gravity of water (i.e. 1), and the surface of the carrier 47 has
As already explained, an aerobic biofilm 50 is formed.

When the wastewater 34 flows into the inner space defined by the reaction tank main body 22' and the gas-liquid separation column 31, and pressurized air is supplied from the air source 27 through the air introduction pipe 26, the carrier 47 The aerobic supernatant film 50 formed on the surface of the carrier 47 and the suspension 48 containing air bubbles 49 circulate and flow as shown by arrows in FIG.

On the other hand, the outer space defined by the jacket 23 and the air wave separator 31 is also open at the top, and the drain pipe 3 of the settling section 33 is opened from the opening at the top.
An input-type interface meter 40 as a surface-elevating sensor is provided at a location below the location where the opening 7 is installed.

This interface 5140 is the interface between the supernatant liquid 5 of the wastewater in the sedimentation section 33 and the surplus l that has precipitated and accumulated below the sedimentation section 33.
r: The interface between the mud 5 and the mud top 2 is detected and a predetermined detection signal is output to the control device 46. The jacket 23 has a drain pipe 38 extending from the top to the bottom thereof.
Three pipes are connected in this order: a drain pipe 37 and a sludge drain pipe 42. Among these three pipes, the drain pipe 38 is connected to the jacket 23 corresponding to the cylindrical part 30 of the gas-liquid separation cylinder 31. The drain pipe 37 opens at a portion of the large diameter cylindrical portion 22 corresponding to the cylindrical portion 28 of the gas-liquid separation tube 31 . The mud drain pipe 42 opens into the inclined portion 21 of the jacket 23. A gate opening valve 36 is provided in front of the drain 37, and
Each of the mud removal pipes 42 is provided with an on-off valve 41 that opens and closes under the control of a control device 46 . Said drain pipe 3
8 and the drain pipe 37 join together on the downstream side of the on-off valve 36, and the supernatant liquid 51 retained in the settling section 33 is drained into a river or the like as treated water 39.

A thickening tank 43 for settling and depositing thickened sludge 54 is connected to the downstream side of the sludge draining pipe 42, and a discharge pipe 45 is connected to the bottom of the thickening tank 43. The discharge pipe 45 is provided with an on-off valve 44 that opens and closes under the control of a control device 46 .

The control device 46 controls the opening/closing operation of the on-off valve 41 and the on-off valve 44 in accordance with the interface detection signal output from the interface meter 40, and also controls the opening/closing operation of the on-off valve 41 and the on-off valve 44, and supplies waste water 34 to the air source 27 and the waste water pipe 35.
It also controls a pump (not shown) that supplies

The on-off valve 36 may be controlled by the control device 46, or may be manually operated by maintenance personnel.

Next, the operation of the water treatment apparatus having the above configuration will be explained.

FIG. 2 is a diagram showing the relationship between suspended sludge concentration and 16-sludge interface height according to the present invention. As shown in FIG. 2, the concentration of the suspension 48 in the inner space defined by the reaction tank main body 22' and the gas-liquid separation cylinder 31, that is, the suspended sludge concentration There is a proportional relationship with the sludge interface height H. The proportionality constant that defines the proportional relationship between the suspended sludge concentration Xs and the sludge field 11j
5, the flow rate of pressurized air given to the reaction tank 20 through the pipe 35 (ventilation flow rate), the flow rate of the waste water 34 given to the reaction tank 20 through the waste water pipe 35 (water flow rate), and the communication port formed in the gas-liquid separation cylinder 31. It is determined by the length of 32, etc. Therefore, by controlling the sludge interface height H, it is possible to maintain the suspended sludge concentration Xs at a constant value. Based on these findings, a process in which an aerobic biofilm 50 is formed on the surface of the carrier 47 carried into the reaction tank 20 (hereinafter referred to as "biofilm formation process") and a surface of the carrier 47 have been developed. Steps after the aerobic biofilm 50 is formed (hereinafter referred to as
We decided to variably adjust the operating mode of the water treatment equipment for each of these steps (referred to as "post-biofilm formation steps"). Hereinafter, an overview of the biofilm formation step and the post-biofilm formation step will be explained with reference to FIG. 3.

(1) Biofilm Formation Step This step is a step in which the suspended sludge concentration Xs is set to a high value to facilitate the formation of an aerobic sludge film 50 on the surface of the carrier 47.

First, seed sludge is poured into the reaction tank 20 by 50% of the total volume of the reaction tank 20.
About 20% of the water is added, and the waste water 34 is made to flow into the reaction tank 20 through the waste water pipe 35. Along with this, the air source 27
Pressurized air is supplied to the aeration pipe 25 through the air introduction pipe 26 by driving the air inlet pipe 26 . The air supplied to the diffuser tube 25 becomes bubbles 49 in the reaction tank 20, and both the carrier 47 and the suspension 48ε rise in the air lift tube 24, and the carrier 47 reaches the top end of the air lift tube 24. Suspension 48
At this top end, the gas is reversed and flows down and circulates through the annular flow path defined by the air lift tube 24, the west wall surface of the gas-liquid separation tube 31, and the inner wall surface of the reaction tank main body 22'. In the process in which the carrier 47 rises together with the suspension 48 and four air bubbles in the air lift tube 24, the wastewater 34 is subjected to aerobic biological treatment. Is this aerobic biological treatment?
@Relation 48, a part of which passes through the communication port 32 and enters the sedimentation part 33
Excess sludge 52 in the suspension 48 flows into the inclined part 21.
As a result, the supernatant liquid 51 and the excess sludge 52 are separated in the settling section 33. The interface of the excess sludge 52 that has settled and accumulated on the slope section 21 in the settling section 33 in this manner is detected by the interface meter 40. When the field meter 40 detects the interface of excess sludge 52 and outputs an interface detection signal to the control device 46, the control device 46 detects the amount of wastewater 34 flowing into the reaction ff120M through the wastewater pipe 35 and the air source 27. By controlling the drive, the interface of the excess sludge 52 in the settling section 33 becomes the fourth
Control is performed so that the first realm 53 is at a high level as shown in the figure. When recognizing that the interface of excess sludge 52 in the settling section 33 has risen above the higher first interface 53 based on the interface detection signal output from the interface 1j15t40, the controller 46 controls the on-off valve 41. The on-off valve 41 is opened to lower the interface of the excess sludge 52. 2, the W of the excess sludge 52 is lowered, and when the interface of the excess sludge 52 is lowered by Δh than the first interface 53 at a higher level by the detection signal output from the hemostatic meter 40, the control device 46
controls the on-off valve 41 to open the on-off valve 4 that had been open until then.
Open the bottom of 1.

By controlling the on-off valve 41 in the manner described above by the control device 46, the excess sludge 52 corresponding to the interface height difference Δh passes through the sludge pipe 42 together with a portion of the supernatant liquid 51 to the thickening tank. 43, the surplus sludge 52 is precipitated and deposited at the bottom of the thickening tank 43 as thickened sludge 54.

As described above, the excess sludge 5 in the settling section 33
The interface of
By controlling the driving of the water treatment device so as to maintain the suspension 48 inside the reaction tank 20 at
The concentration of is 2.000 to 10,000 .mu./g. When the concentration of the suspension 48 increases in this manner, the number of microorganisms in the suspension 48 becomes diversified, and many types of microorganisms adhere to the surface of the carrier 47. Then, an aerobic biofilm 50 is formed on the surface of the carrier 47 over a period of about 1 to 2 weeks, and the biofilm concentration in the suspended rIJ liquid 48 is reduced to 1. ．． 0(') 0 to 2.00 (1■/g.

(2) Post-biofilm formation process This process is a process of reducing the concentration of the suspension 48 in the reaction tank 20 and mainly performing water treatment using an aerobic biofilm 50, and includes three steps detailed below. That is, this process is completed by sequentially repeating the normal operation process, carrier regeneration process, and return process.

(2-1) Normal operation process In this normal operation process, the control device 46 controls the excess sludge in the settling section 33 based on the detection signal output from the interface meter 40.
This is a step of variably adjusting and maintaining the second interface 55 at a lower level as shown in FIG. Based on the detection signal output from the interface meter 40, when it is recognized that the interface of excess sludge 52 in the settling section 33 has risen above the lower second interface 55 shown in FIG.
controls the on-off valve 41 to open the on-off valve 41, thereby lowering the interface of the excess sludge 52. In this way, excess sludge 5
When the interface of excess sludge 52 is lowered by Δh than the lower second interface 55 based on the detection signal output from the interface meter 40, the controller 46 controls the on-off valve 41 to The on-off valve 41, which had been open, is opened. By controlling the on-off valve 41 in the manner described above by the control device 46, the excess sludge 52 corresponding to the interface height difference Δh is transferred to the sludge pipe 42 along with a portion of the supernatant liquid 51.
The surplus sludge 52 flows into the thickening tank 43 through the thickening tank 43, and the surplus sludge 52 is precipitated and deposited at the bottom of the thickening tank 43 as thickened sludge 54.

As described above, the excess sludge 5 in the settling section 33
The interface of
The suspension 48 inside the reaction tank 20 is
The concentration can be maintained at 100 to 1,000 II1g/jJ. In this way, when the concentration of the suspension 48 decreases, the load on the aerobic biofilm 50 increases, so that the concentration of the aerobic biofilm 50 decreases by 2.
The concentration is increased to 000 to 5,000 mg/47. Then, a water treatment operation mainly using the aerobic biofilm 50 will be executed.

(2-2) Carrier regeneration process This carrier regeneration process is performed by removing the aerobic biofilm 50 that has grown excessively on the surface of the carrier 47 carried into the reaction tank 20.
This is a step of regenerating the carrier 47 by peeling it off. In the normal operation process described above, when the thickness of the aerobic biofilm 50 increases to 0.5 degrees or more, the carrier 47 is regenerated in this process. Close the on-off valve 36,
The overflow surface 51' (that is, the surface from which water overflows) is connected to the drain pipe 3.
When raised to the height where 8 is open, this creates severe turbulence in the upper part of the air lift tube 24. Aerobic biofilm 50 due to concentration of air bubbles 49 and strong turbulence
A large shearing force is applied to the carrier 47, and it is easily peeled off from the carrier 47. The detached organisms @50 are accumulated as surplus 19E52 in the sedimentation section 33.

(2-3) Restoration Step This step is a step for transitioning from the above-mentioned carrier regeneration step to the normal operation step, which is the first step. By opening the on-off valve 36 that was closed in the carrier regeneration step, the overflow surface that has reached the height where the drain pipe 38 is open is
It is lowered to the height at which the drain pipe 37 is open. By lowering the overflow surface to the level at which the drain pipe 37 is opened in this manner, the turbulent flow generated in the carrier regeneration operation step described above disappears, resulting in a gentle flow. During execution of this step, the interface of the surplus tQ mud 52 in the settling section 33 is controlled to be the lower second W surface 55 described above. By executing this step, the normal operation step described above will be restored.

In the process explained above, the W curve H of the excess sludge 52, the concentration of the suspension 48, that is, the floating a shield sludge concentration Xs, and the aerobic biofilm 5
The change over time of the 0 film JIj1'μ is as shown in FIG. Note that the downward arrow in FIG. 3 indicates the operating state of the on-off valve 41 described above.

As explained above, according to the first embodiment of the present invention, since the drop-in type interface meter 40 is used as the interface sensor, the installation area of the interface sensor within the reactive species 20 is reduced, and the water treatment It is possible to make the entire device more compact.

In addition, gas-liquid separation tubes 31 with different diameters on the upper and lower sides are arranged in the reaction tank 20, and the air lift tube 24 can be opened and closed only by opening and closing the on-off valve 36.
Since the turbulent flow inside can be controlled, the three steps that make up the post-biofilm formation process: the normal operation step, the carrier regeneration step, and the return step can be easily carried out, thereby reducing running costs. is now also possible. The above-mentioned contents are strictly related to one-length embodiments according to the present invention, and it goes without saying that the present invention is not limited to only the above-mentioned contents.

FIG. 6 is a schematic explanatory diagram showing the overall configuration of a water treatment device according to another embodiment of the present invention.

In this embodiment, a plurality of turbidity meters (four in this embodiment) are arranged in the sedimentation section 33 as an interface sensor instead of the input-type interface meter 40 used in the previous embodiment. The configuration is such that There are various types of interface sensors other than the input-type interface meter 40 used in the embodiment described above.

Therefore, any means may be used as long as it can detect the interface of excess sludge 52 within settling section 33.

In Fig. 6, the lower part of the sediment 33, which forms a reaction tank 20, and a constant interval from the position of the inclined portion 21, a turbidity meter 60, a turbidity meter 61, a turbidity meter 62, a turbidity. A meter 63 is provided respectively.

Each of the turbidity meters 60.61. ．． The output sides of 62 and 63 are electrically connected to the input side of the control device 46, respectively.

In the above configuration, the control device 46 reads the detection signal output from the turbidity 5163 installed at the top of the settling section 33 into the turbidity 62.61.6.
The detection signals output from each turbidity; 1- are read in the order of 0. In the process of such a detection signal reading operation, when a detection signal indicating a sudden shift in turbidity is output,
The control device 46 disables the installation of the turbidity meter that outputs this detection signal when the amount of excess sludge 52 in the sedimentation section 33 increases.

In addition, the following operation mode is the same as the operation mode of the water treatment apparatus in the said Example. In this embodiment and the embodiments described above, the interface height of the excess sludge 52 in the settling section 33 was controlled by the control device 46, but the control device 46
A timer may be used instead of 6.

As explained above, according to another embodiment of the present invention, four turbidity meters (turbidity meters 60, 61, 62, 63) are installed in the settling section 33 forming the reaction tank 20. Therefore, as in the above-mentioned embodiment, the world-style interface meter 40,
The interface meter 4 fluctuates up and down in response to fluctuations in the amount of supernatant liquid 51 and surplus sludge 52 staying in the settling section 33.
0 and the control device 46, or the signal transmission line is loosened more than necessary, and no stress is placed on the signal transmission line, and maintenance of the device is facilitated. It has become possible to further reduce the running cost of the device.

〔Effect of the invention〕

As explained above, according to the present invention, the interface of sludge in the sedimentation mechanism is detected, and based on the detection of the interface of sludge, a biofilm is formed on the carrier located inside the wastewater treatment mechanism. In the biofilm formation step, the height of the sludge interface in the sedimentation mechanism is within a height region in which sludge does not flow out from the sedimentation mechanism, while in the subsequent step following the biofilm formation step, Since it was decided to control the crystallinity of the sludge interface in each of the steps described above so that the height of the sludge interface in the sedimentation mechanism was lower than that in the biofilm formation step, the startup of the water treatment equipment time (i.e.
When starting up the water treatment equipment), it promotes the formation of an IR biofilm on the surface of the carrier carried into the wastewater treatment mechanism, and during continuous operation of the water treatment equipment,
By suppressing and preventing the sludge precipitated and accumulated in the sedimentator from flowing out into rivers etc. along with the treated water, stable water treatment can be performed with high reliability and maintenance.
It is possible to provide a water treatment device that is easy to push forward.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the overall configuration of a water treatment device according to an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between suspended sludge concentration and sludge interface height according to the present invention, and FIG. The diagram is
Explanatory diagram of the operation of the water treatment device according to an embodiment of the present invention, No. 4
5 and 5 are explanatory diagrams showing operating modes during biofilm formation operation and commercial operation according to the present invention, and FIG. 6 is an overall view of a water treatment apparatus according to another embodiment of the present invention. FIG. 7, a schematic explanatory diagram showing the configuration, is a partial schematic vertical sectional view showing the configuration of the water treatment facility F11 device according to the prior art. 20...Reaction tank, 22'...Reaction (θ main body, 23
...Jacket, 24...Airlift pipe, 25...
・Air diffuser pipe, 26... Air introduction pipe, 27... Air source,
33... Sedimentation part, 34... Waste water, 35... Waste water pipe, 40... Interface meter, 41... Open/close valve, 42... Sludge drainage pipe, 46... Control device, 47 ...Carrier, 48...
・Kake EJ Ki, 49... Air bubbles, 50... Aerobic biofilm, 51... Supernatant liquid, 52... Excess sludge, 53...
・The first ascension of the high rank, 55...the second interface of the low rank.

Claims (1)

[Scope of Claims] Organisms formed on the carrier that contain a carrier on which a biofilm is formed and wastewater flowing in from the outside, and circulate and flow the wastewater and the carrier with pressurized gas supplied from the outside. a wastewater treatment mechanism that processes the wastewater with a membrane; and a sedimentation mechanism that communicates with the wastewater treatment mechanism and receives the treated water treated by the wastewater treatment mechanism and separates the treated water into supernatant liquid and sludge. , detecting the interface of the sludge separated in the settling mechanism,
an interface detection means for outputting a predetermined detection signal; and a biofilm formation step in which a biofilm is formed on the carrier in response to the detection signal from the interface detection means; On the other hand, in the post-process following the biofilm formation step, the height of the sludge interface in the settling mechanism is lower than that in the biofilm formation step so that the height of the sludge interface in the settling mechanism falls within the area. A water treatment device comprising: control means for controlling the height of the sludge interface in each of the steps so that the height of the sludge interface is lowered.