JP3181468B2 - Sewage treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewage treatment apparatus used for domestic sewage treatment, sewage treatment, industrial sewage treatment, etc., and more particularly to sewage treatment capable of performing an activated sludge method and a membrane separation method regardless of fluctuations in the amount of inflowed sewage. Related to the device.

[0002]

2. Description of the Related Art As a wastewater treatment apparatus used for domestic wastewater treatment, sewage treatment, industrial wastewater treatment and the like, for example, the one shown in FIG. 2 is known. In such a sewage treatment apparatus, water to be treated is introduced from the water to be treated supply pipe 31 and impurities are removed while passing through a filtration unit 33 provided with a screen 32 and the like. While being stored in the receiving chamber 34, an appropriate amount thereof is guided to the aeration chamber 36 by an air lift pump 35 or the like.

[0003] The water to be treated is mixed with the activated sludge mixture in the aeration chamber 36, and aerated air is supplied under aerobic conditions by supplying aerated air through an aeration device 38 from an air supply means such as a blower 37. The organic sludge and the nitrogen content in the water to be treated are removed by the action of the activated sludge while stirring using the water. Further, suction negative pressure is supplied by the pump 40 to the filtrate side of the membrane separation device 39 provided by immersion in the activated sludge mixture,
By generating a pressure difference between the front and back of the filtration membrane, solid-liquid separation is performed by the filtration membrane, the activated sludge remains in the room, and the filtrate that has passed through the filtration membrane is taken out.

[0004] The filtrate is guided to a disinfection unit 41 and disinfected by a sterilizer 42 so as not to impair sanitation. Thereafter, the filtrate is discharged to the outside of the apparatus as a purified water 44 through a filtrate chamber 43.

At this time, a liquid level gauge 45 and a liquid level gauge 46 are provided above the inside of the receiving chamber 34 and above the membrane separation device 39, respectively, based on the liquid levels measured by these liquid level gauges 44 and 45. Thus, the inflow amount of the water 31 to be treated and the amount of the filtrate to be withdrawn by the pump 40 are adjusted, and the minimum liquid level L of the activated sludge mixed liquid for maintaining the filtration membrane in the immersion state is ensured.

[0006]

However, if the above-mentioned sewage treatment apparatus is to be used as a small-sized combined clarification tank with a size of 5 to 50 persons, the suction pump or the sewage treatment apparatus is limited due to cost, equipment reliability, and maintenance and management. The installation of a liquid level gauge is difficult and has not been put to practical use at present.

[0007] In addition, since the merged septic tank generally has a larger fluctuation in the amount of inflowing sewage as the scale becomes smaller, a flow rate adjusting function is indispensable for introducing a membrane separation method.
In addition, in the conventional membrane separation method, a constant flow rate filtration is generally performed in order to maintain a long interval for washing the filtration membrane, and a flow rate adjustment function is required to perform the constant flow rate filtration in a state where the amount of inflowed sewage fluctuates. Is required.

An object of the present invention is to solve the above-mentioned problem and to provide a sewage treatment apparatus capable of performing activated sludge treatment and membrane separation treatment irrespective of fluctuations in the amount of inflowed sewage while having a simple structure. .

[0009]

In order to solve the above-mentioned problems, a sewage treatment apparatus according to the present invention is capable of biologically treating treated water introduced from a treated water supply pipe with activated sludge under aerobic conditions. An aeration chamber for processing is provided, and a membrane separation device for solid-liquid separation of the activated sludge mixed liquid is provided inside the aeration chamber using the natural head of the room as a driving pressure, and the filtrate chamber separated via the partition from the aeration chamber is provided. setting only, connecting the filtrate pipe and the aeration chamber and the filtrate chamber
And one end of the filtrate tube is connected to the membrane permeation side of the membrane separator, and the other end is communicated with the filtrate chamber at an appropriate position below the top of the membrane separator, and an electromagnetic valve is installed at the other end of the filtrate tube. Control means for controlling the intermittent opening and closing of this solenoid valve.
Control, the liquid level in the aeration chamber is controlled by the membrane separation device.
Driving the natural head in the aeration chamber by maintaining it within a certain range above
As the pressure, the activated sludge mixture is solid-liquid separated by a membrane separation device .

[0010]

According to the above construction, the water to be treated introduced into the aeration chamber is mixed with the activated sludge in the room, and is biologically treated by the action of the activated sludge under aerobic conditions. By a membrane separation device provided by immersion, solid-liquid separation is performed using the natural head in the room as a driving pressure. At this time,
Since the other end of the filtrate tube is guided to the filtrate chamber at an appropriate position below the top of the membrane separation device, the natural head in the aeration chamber is used as a large driving pressure.

[0011] Then, when the inflow of the water to be treated into the aeration chamber increases and the liquid level in the room rises and the natural head increases,
When the filtration rate increases and, conversely, the flow rate of the water to be treated into the aeration chamber decreases, the liquid level in the room decreases, and the natural head decreases, so that the filtration rate decreases. In this way, as a result of the filtration speed automatically changing in accordance with the change in the inflow of the water to be treated, the influence of the change in the inflow of the water to be treated is reduced.

When the liquid level in the aeration chamber drops to a certain lower limit liquid level above the membrane separation device due to the balance between the inflow amount of the water to be treated and the filtrate volume sent to the filtrate chamber, the control means The solenoid valve is closed, solid-liquid separation is stopped,
Thereafter, when the liquid level in the aeration chamber rises and reaches a certain upper limit liquid level above the membrane separation device, the solenoid valve is opened and solid-liquid separation is restarted. In this way, solid-liquid separation is performed while maintaining the membrane separation device in the activated sludge mixture and further intermittently opening and closing the electromagnetic valve by the control means.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a sewage treatment apparatus according to one embodiment of the present invention. A main body 1 is an aeration chamber for biologically treating treated water introduced from a treated water supply pipe 2 with activated sludge under aerobic conditions. 3 and an aeration chamber 3 and a filtrate chamber 5 separated via a partition 4. The filtrate chamber 5 is provided with a discharge pipe 6.

In the aeration chamber 3, there is provided a filtration unit 8 provided with a screen 7 and the like, covering the opening of the water supply pipe 2 to be treated, and measuring the liquid level of the activated sludge mixed liquid in the room at the upper part. The liquid level gauge 9 is connected to a control device 9a having a timer function. In addition, an immersion type membrane separation device 10 is provided in the vicinity of the partition 4 for solid-liquid separation of the activated sludge mixture by using the natural head in the room as a driving pressure.
The aeration chamber 3 is configured such that the maximum head difference is 2 m.

In the membrane separation device 10, membrane cartridges 12 are arranged in parallel at an appropriate interval inside a box-shaped casing 11 having an open top and bottom. And suction header tube 14
Are sequentially provided. A filtrate tube 15 is provided so that one end thereof communicates with the suction header tube 14, and the other end of the filtrate tube 15 is 5 to 10 mm below the membrane cartridge 12.
The liquid is guided into the filtrate chamber 5 through the partition wall 4 at an appropriate position below the centrifuge. The other end of the filtrate tube 15 is provided with an electromagnetic valve 16 connected to the control device 9a. Below the membrane cartridge 12, an aeration device 17 for supplying aerated air to the water to be treated is provided connected to a blower 18.

In the filtrate chamber 5, a disinfecting section 20 having a sterilizer 19 is provided so as to cover the opening of the discharge pipe 6, and a pump 21 for guiding the water to be treated in the chamber 5 to the disinfecting section 20 is provided. Is provided.

Openings 22 and 23 for maintenance management are formed in the top of the apparatus, and lids 22a and 23 are respectively provided.
a is provided. Hereinafter, the operation of the above configuration will be described.

When the water to be treated is introduced from the water supply pipe 2, foreign matter is removed by a screen 7 or the like while the water to be treated passes through the filtration unit 8, and then the activated sludge mixed liquid in the aeration chamber 3 is removed. Is mixed. The water to be treated is biologically treated by the action of activated sludge while being agitated by the bubble flow of the aerated air under aerobic conditions in which the aerated air is supplied from the blower 18 through the aerator 17. The organic matter and nitrogen contained in are removed.

Further, the activated sludge mixture in the aeration chamber 3 drives a wide natural water head which can be used by guiding the other end of the filtrate pipe 15 to the filtrate chamber 5 at an appropriate position below the lower portion of the membrane cartridge 12. As pressure, the membrane cartridge 12
Is separated into solid and liquid. Then, the activated sludge is maintained in the room, and the filtrate that has passed through the filtration membrane is sent from the filtrate tube 15 to the filtrate chamber 5 through the suction tube 13 and the suction header tube 14.

At this time, the liquid level in the aeration chamber 3 is measured by the liquid level meter 9, and the liquid level in the aeration chamber 3 is determined based on the balance between the inflow of the water to be treated and the amount of the filtrate sent to the filtrate chamber 5. And the liquid level L at a certain lower limit above the membrane cartridge 12
When L has been reached, the solenoid valve 16 is closed by the control device 9a based on the electric signal sent from the liquid level meter 9,
The solid-liquid separation is stopped. When the liquid level in the aeration chamber 3 rises and reaches a certain upper limit liquid level HL above the membrane cartridge 12, the electromagnetic valve 16 is controlled by the control device 9a.
Is opened, and the solid-liquid separation is restarted. In this way, solid-liquid separation is performed while maintaining the membrane separator 10 in the activated sludge mixture and intermittently opening and closing the electromagnetic valve 16 by the timer function of the controller 9a.

During the intermittent solid-liquid separation as described above, if the flow rate of the water to be treated into the aeration chamber 3 increases and the natural head increases, the filtration rate increases. When the flow rate of the water to be treated into the chamber 3 decreases and the natural head decreases, the filtration rate decreases. As a result,
The effect of the fluctuation of the inflow of the water to be treated is reduced, and the space in the aeration chamber 3 for storing the water to be treated can be reduced.

In the above-mentioned intermittent operation method, the permeation flux was measured while changing the water head using a microfiltration membrane having an average pore diameter of about 0.4 μm, 1 μm and 3 μm. Although the permeation flow rate was reduced due to clogging, all of the filtration membranes were able to perform filtration using the natural head alone for more than half a year as compared with the continuous operation method. Also, when washing these filtration membranes, the solid-liquid separation is performed by utilizing the head difference, so that the membrane surface deposits do not become firm and dense as in the conventional method of suction filtration using a pump or the like. Washing was easy.

The water to be treated that has flowed into the filtrate chamber 5 is guided to a disinfecting section 19 by a pump 20 as appropriate, and after being disinfected by a sterilizer 18, is discharged from the discharge pipe 6 to the outside of the apparatus.
The water to be treated that has flowed into the filtrate chamber 5 is allowed to flow by gravity to the disinfection unit 1
The device may be configured to be directed to 9. When maintenance of the apparatus is required, the lids 21a and 22a are opened and work is performed through the openings 21 and 22.

[0024]

As described above, according to the present invention, the activated sludge mixed liquid in the aeration chamber is solid-liquid separated by the membrane separation device using the natural head in the room as the driving pressure, and the filtrate is collected at the top of the membrane separation device. At the appropriate position below, the filtrate is sent to the filtrate chamber by the filtrate tube, without using a pump.
Solid-liquid separation can be performed using the natural head of the room widely. At this time, since the filtration speed automatically changes in accordance with the fluctuation of the natural head, a separate receiving tank is provided to adjust the fluctuation of the inflow of the water to be treated, or a large space is provided above the membrane device. It becomes unnecessary. Further, the liquid level in the aeration chamber is maintained at a certain level above the membrane separation device by the solenoid valve, so that the membrane separation device can be maintained in the immersion state. Further, since the membrane separator is operated intermittently by the solenoid valve, no hard and dense deposits are formed on the membrane surface, so that the washing interval of the filtration membrane can be lengthened and washing becomes easy.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of a sewage treatment apparatus according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an overall configuration of a conventional sewage treatment apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sewage treatment apparatus 2 To-be-processed water supply pipe 3 Aeration chamber 4 Partition wall 5 Filtrate chamber 9 Liquid level meter 9a Control device 10 Membrane separation device 15 Filtrate pipe 16 Solenoid valve

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C02F 3/12 C02F 3/00

Claims (1)

(57) [Claims] An aeration chamber for biologically treating treated water introduced from a treated water supply pipe with activated sludge under aerobic conditions is provided, and a natural water head in the room is driven inside the aerated chamber by a driving pressure. A membrane separation device for solid-liquid separation of the activated sludge mixed liquid is provided as the above, and the aeration chamber and a filtrate chamber separated via a partition are provided.
The aeration chamber and the filtrate chamber are connected by a filtrate tube.
Connect one end of the tube to the membrane permeation side of the membrane separation device,
The other end is communicated with the filtrate chamber at an appropriate position below the top of the membrane separation device, and an electromagnetic valve is installed at the other end of the filtrate tube,
A control means for intermittently controlling the opening and closing of the solenoid valve is provided.
To maintain the liquid level in the aeration chamber above the membrane separator.
The membrane is maintained within the range and the natural head in the aeration chamber is used as the driving pressure.
A sewage treatment apparatus characterized in that the activated sludge mixed liquid is separated into solid and liquid by a separator .