JP2001017970A - Water treatment equipment using immersion type membrane filtration device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To successively perform membrane filtration treatment of raw water in an anaerobic vessel by providing a water treatment equipment with a reaction vessel into which raw water flows, an immersion type membrane filtration device immersed in the reaction vessel and an ultrasonic wave irradiation means for irradiating the inside of a liquid in the reaction vessel with ultrasonic waves. SOLUTION: This equipment is provided with: a reaction vessel 22 into which raw water flows through a raw water supply pipeline 21; an immersion type membrane filtration device 23 immersed inside the reaction vessel 22, wherein the membrane filtration device 23 consists of a membrane module having plural tubes of ceramic tubular filtration membrane and is connected to a suction pump 24 for applying a driving pressure to the membrane module through a liquid permeate suction pipeline 25 and an organic membrane can also be used for the membrane module; an air diffuser pipe 26 placed below the membrane filtration device 23 inside the reaction vessel 22; a blower 27 that is used for supplying air to the air diffuser pipe 26 and placed outside the reaction vessel 22; and an ultrasonic wave irradiation device 28 having an ultrasonic wave irradiation section 28a placed inside the reaction vessel 22, and an ultrasonic generator 28b that is used for transmitting ultrasonic waves to the ultrasonic wave irradiation section 28a through a waveguide and placed outside the reaction vessel 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to water treatment techniques such as water purification treatment, sewage treatment, industrial wastewater treatment, landfill leachate treatment, human waste treatment, and the like, and relates to a water treatment facility using a submerged membrane filtration device. is there.

[0002]

2. Description of the Related Art Conventionally, as this type of water treatment equipment, for example, there is one shown in FIG. In FIG. 2, a immersion type membrane filtration device 3 is disposed in a reaction tank 2 into which raw water flows through a raw water supply pipe 1, and an air diffusion tube 4 is provided below the immersion type membrane filtration device 3.
And a blower 5 for supplying diffused air to the diffuser tube 4 is disposed outside the tank.

[0003] The immersion type membrane filtration device 3 immerses a membrane module provided with a filtration membrane of an ultrafiltration membrane and a microfiltration membrane in a tank,
A suction pump 7 is arranged in a permeated liquid suction pipe 6 for taking out the permeated liquid permeating the membrane module out of the tank.
The liquid in the tank is filtered using the suction pressure of the above as the driving pressure. The permeate suction pipe 6 communicates with the storage tank 8, and the storage tank 8 and the permeate suction pipe 6
, A backwash water supply pipe 9 is provided. The backwash water supply pipe 9 has a distal end side upstream of the suction pump 7 and a permeated liquid suction pipe 6.
And a backwash pump 10 is provided in the middle.

In this configuration, air is supplied through a diffuser 4 by a blower 5, and an upward flow generated by an air lift action of this air is supplied to the immersion type membrane filtration device 3 in a cross flow, so that the membrane surface faces upward. The immersion type membrane filtration device 3 is driven while washing with a stream. The immersion type membrane filtration device 3 has a suction pump 7
The raw water flowing into the reaction tank 2 through the raw water supply pipe 1 is filtered, and the treated water (permeate) that has passed through the membrane module is supplied to the storage tank 8 through the permeate suction pipe 6. .

The pollutants (cake layer) adhering to the membrane surface of the membrane module of the immersion type membrane filtration device 3 are washed by a regular backwashing operation. In the backwashing operation, the backwash pump 10 is started in a state in which the suction pump 7 is stopped, the treated water in the storage tank 8 is supplied to the permeated liquid suction pipe 6 through the backwash water supply pipe 9, and the treated water is supplied to the membrane module. Perform by pumping.

[0006]

In the above-mentioned conventional configuration, the immersion type membrane filtration device 3 is liable to be clogged by pollutants adhering to the membrane surface thereof. It is necessary to wash the membrane surface in countercurrent and to perform regular water backwashing at a relatively high frequency. In this water backwash, the filtration operation is stopped, and the immersion type membrane filtration device 3 is used.
When the frequency of water backwash increases, the total time for stopping the filtration operation increases, and in order to compensate for this loss time, the immersion type membrane filtration device 3 is used.
It is necessary to provide extra processing capacity beyond that required for normal operation. In addition, since it is essential to diffuse air to clean the membrane surface during operation, the inside of the tank becomes oxygen-rich, so even if it can be applied to an aerobic tank, it can be applied to an anaerobic tank. Could not be applied.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a water treatment facility using an immersion type membrane filtration device capable of performing a membrane filtration treatment in an anaerobic tank.

[0008]

In order to solve the above-mentioned problems, a water treatment facility using the immersion type membrane filtration apparatus of the present invention comprises a reaction tank into which raw water flows, and a immersion type membrane filtration apparatus immersed in the reaction tank. And ultrasonic irradiation means for irradiating ultrasonic waves into the liquid in the reaction tank. According to the above configuration, the ultrasonic wave irradiated from the ultrasonic irradiation means into the liquid in the reaction tank causes the membrane surface of the immersion type membrane filtration device to ultrasonically vibrate, thereby suppressing the adhesion of pollutants to the membrane surface. At the same time, the pollutants are peeled off from the membrane surface.

Therefore, it is possible to operate the immersion type membrane filtration device while suppressing the temporal decrease of the permeation flux without performing the conventional backwashing with water or washing with air diffusion. Moreover, since the ultrasonic waves contribute to the decomposition of trace harmful substances in raw water, for example, dioxins and agricultural chemical components, trace harmful substances in treated water can be reduced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a reaction tank 22 into which raw water flows through a raw water supply pipe 21 has a submerged membrane filtration device 23 immersed therein. The immersion type membrane filtration device 23 is composed of a membrane module having a plurality of tubular filtration membranes made of ceramic, and a suction pump 24 for applying a driving pressure to the membrane module is connected via a permeated liquid suction pipe 25. It is also possible to use an organic membrane for the membrane module of the immersion type membrane filtration device 23.

A diffuser 2 is provided below the immersion type membrane filtration device 23.
6 is arranged, and a blower 27 for supplying air to the air diffuser 26 is arranged outside the tank. An ultrasonic irradiation unit 28a of an ultrasonic irradiation device 28 is disposed inside the reaction tank 22, and an ultrasonic oscillator 28b that sends ultrasonic waves to the ultrasonic irradiation unit 28a through a waveguide is disposed outside the tank. The permeate suction pipe 25 communicates with the storage tank 29, and the permeate suction pipe 25 upstream of the suction pump 24 communicates with the storage tank 29 to provide a backwash water supply pipe 30. 30 is provided with a backwash pump 31.

The operation of the above configuration will be described below. First, a case where the reaction tank 22 is operated as an anaerobic tank will be described. The operation of the blower 27 is stopped to maintain the reaction tank 22 in an oxygen-free state or an oxygen-deficient state, and sewage sludge or the like supplied as raw water from the raw water supply pipe 21 to the reaction tank 22 is biologically treated by anaerobic microorganisms. At this time,
The ultrasonic irradiation device 28 is started, and ultrasonic waves are sent from the ultrasonic oscillator 28b to the ultrasonic irradiation unit 28a.
Ultrasonic waves are applied from a to the immersion type membrane filtration device 23 into the liquid in the tank. The irradiated ultrasonic waves are trace harmful substances in sludge,
For example, it contributes to the decomposition of dioxins and pesticide components, and reduces trace harmful substances.

On the other hand, the suction pump 24 is driven to apply a suction negative pressure to the immersion type membrane filtration device 23, the liquid in the tank is filtered by the membrane module, and the filtered treated water is passed through the permeated liquid suction pipe 25 to the storage tank 29. send. At this time, the ultrasonic wave applied to the liquid in the tank causes the membrane surface of the immersion type membrane filtration device 23 to ultrasonically vibrate, thereby preventing the pollutant from adhering to the membrane surface and peeling the pollutant from the membrane surface. Let it. Therefore, it is possible to operate the immersion type membrane filtration device 23 while suppressing the permeation flux from decreasing with time, without performing the conventional backwashing with water or washing with air diffusion.

The immersion type membrane filtration device 23 is backwashed with water as needed. In the water backwashing, the operation of the suction pump 24 is stopped, and the backwash pump 31 is driven to pump the treated water in the storage tank 29 through the backwash water supply pipe 30 to the membrane module of the immersion type membrane filtration device 23. Do. At this time, since the contaminants adhering to the membrane surface are in a state of being easily peeled off by the ultrasonic vibration, a sufficient washing effect can be obtained by a small amount of backwash water.

When the reaction tank 22 is operated as an aerobic tank, the blower 27 is started, and air is diffused from the diffusion tube 26 into the liquid in the reaction tank 22. At this time, since the contaminants attached to the membrane surface are removed by ultrasonic vibration, the amount of air diffused from the air diffuser 26 is only required for biological treatment by aerobic microorganisms. Since a large amount of air required for cleaning the membrane surface is not required, the blower 2
7 can be reduced. Also in this case, the ultrasonic waves contribute to the decomposition of trace harmful substances in the sludge.

[0016]

As described above, according to the present invention, the membrane surface of the immersion type membrane filtration device is ultrasonically vibrated by irradiating ultrasonic waves into the liquid in the reaction tank, and the membrane surface is contaminated. A immersion type membrane filtration device that suppresses the permeation flux over time without performing backwashing with water or washing by air diffusion, as it suppresses the adhesion of substances and separates contaminants from the membrane surface. Can be driven. The frequency of water backwashing can be suppressed, and pollutants are easily peeled off by ultrasonic vibration. Therefore, a sufficient washing effect can be obtained with a small amount of treated water. Moreover, the ultrasonic waves can decompose dioxins and pesticide components, which are trace harmful substances in raw water, and reduce trace harmful substances in treated water.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a water treatment facility according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a conventional water treatment facility.

[Explanation of symbols]

 Reference Signs List 21 Raw water supply pipe 22 Reaction tank 23 Immersion type membrane filtration device 24 Suction pump 25 Permeate suction pipe 26 Air diffuser 27 Blower 28 Ultrasonic irradiation device 28a Ultrasonic irradiation unit 28b Ultrasonic oscillator 29 Storage tank 30 Backwash water supply pipe 31 Backwash pump

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C02F 3/12 C02F 3/12 S 3/28 3/28 A F term (reference) 4D006 GA06 GA07 HA21 HA93 KA31 KB22 KB23 KC03 KC13 KC19 MA02 MC03X PA01 PA02 PB08 PC61 PC62 4D028 BC17 BD00 BD17 4D040 AA31

Claims (1)

[Claims] 1. A reaction tank into which raw water flows, an immersion type membrane filtration device immersed in the reaction tank, and ultrasonic irradiation means for irradiating ultrasonic waves into the liquid in the reaction tank. Water treatment equipment using a submerged membrane filtration device.